B-VHF Reference Environment

www.B-VHF.org

Project co-funded by the European Community within the 6th Framework Programme (2002-2006)

REPORT D-08 B-VHF Reference Environment

PROJECT NUMBER: AST3-CT-2003-502910

PROJECT ACRONYM: B-VHF

PROJECT TITLE: BROADBAND VHF AERONAUTICAL COMMUNICATIONS

SYSTEM BASED ON MC-CDMA

INSTRUMENT: SPECIFIC TARGETED RESEARCH PROJECT

THEMATIC PRIORITY: AERONAUTICS AND SPACE

PROJECT START DATE: 01.01.2004

DURATION: 30 MONTHS

PROJECT CO-ORDINATOR: FREQUENTIS GMBH (1) (FRQ) A

PRINCIPAL CONTRACTORS: DEUTSCHES ZENTRUM FÜR LUFT UND RAUMFAHRT E.V. (2) (DLR) D

NATIONAL AIR TRAFFIC SERVICES (EN ROUTE) PLC (3) (NERL) UK

LUFTHANSA GERMAN AIRLINES (4) (LH) D

BAE SYSTEMS (OPERATIONS) LTD (5) (BAES) UK

SCIENTIFIC GENERICS LTD (6) (SGL) UK

UNIVERSITEIT GENT (7) (UGent) B

UNIVERSIDAD POLITECNICA DE MADRID (8) (UPM) E

PARIS LODRON UNIVERSITAET SALZBURG (9) (UniSBG) A

DEUTSCHE FLUGSICHERUNGS GMBH (10) (DFS) D

UNIVERSIDAD DE LAS PALMAS DE GRAN CANARIA (11) (ULPGC) E

DOCUMENT IDENTIFIER: D-08

REVISION: 1.0

DUE DATE: 28.01.2005

SUBMISSION DATE: 22.04.2005

LEAD CONTRACTOR: FREQUENTIS

DISSEMINATION LEVEL: PU - PUBLIC

DOCUMENT REF: 04A02 E515.10

Contract number: AST3-CT-2003-502910 Report number: D-08 Issue: 1.0

File: D8_Reference Environment_10.doc Author: Frequentis

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History Chart

Issue Date Changed Page (s) Cause of Change Implemented by

DRAFT 0.1 14.12.2004 All sections New document Frequentis

DRAFT 0.2 06.04.2005 Modified sections 4, 6, 10, 12 , minor editorial changes in other sections, added sections 2, 3, 9, 11, 13

NERL, LH and UniSBG comments

Frequentis

1.0 18.04.2005 Minor changes in section 11

UniSBG corrections

Frequentis

Authorisation

No. Action Name Signature Date

1 Prepared M. Sajatovic 2005-04-18

2 Approved B. Haindl 2005-04-19

3 Released C. Rihacek 2005-04-20

The information in this document is subject to change without notice.

All rights reserved.

The document is proprietary of the B-VHF consortium members listed on the front page of this document. No copying or distributing, in any form or by any means, is allowed without the prior written agreement of the owner of the proprietary rights.

Company or product names mentioned in this document may be trademarks or registered trademarks of their respective companies.

CCMU



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Contents

1. Introduction .................................................................1-1 1.1. B-VHF Project Description ............................................................... 1-1 1.2. B-VHF Project Work Breakdown ....................................................... 1-2

2. Executive Summary.......................................................2-1

3. Scope..........................................................................3-1

4. Reference Airspace........................................................4-1 4.1. Rationale for the Reference Airspace Selection ................................... 4-1 4.2. United Kingdom - Division of Airspace............................................... 4-1 4.3. Controlled Airspace ........................................................................ 4-2 4.4. Uncontrolled Airspace ..................................................................... 4-5 4.5. Airspace Rules............................................................................... 4-5 4.6. Separation Standards ..................................................................... 4-6 4.7. Control of Airspace in the United Kingdom......................................... 4-7 4.8. ATC Voice Communications System – Operational Requirements......... 4-14 4.9. Frequency Planning ...................................................................... 4-14 4.10. NERL Radio System Description ..................................................... 4-15 4.11. RF Coverage from NATS Airports.................................................... 4-15 4.12. RF Coverage from NERL Radio Stations ........................................... 4-16 4.13. Multi-carrier Operations ................................................................ 4-17 4.14. Radio Station Configuration ........................................................... 4-19 4.15. Radio Function............................................................................. 4-19 4.15.1. Transmit Function ........................................................................ 4-19 4.15.2. Receive Function.......................................................................... 4-20 4.16. Aerial Systems ............................................................................ 4-20 4.17. RF Design ................................................................................... 4-20 4.18. Ground to Air Communications – Regulatory Issues .......................... 4-20 4.19. Representative UK Airport ............................................................. 4-21 4.19.1. ATIS Frequencies......................................................................... 4-21



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4.19.2. ATC Frequencies .......................................................................... 4-22 4.19.3. Usage Scenario for Airport Frequencies – Departing Aircraft ............... 4-24 4.19.3.1. Departure ATIS ........................................................................... 4-24 4.19.3.2. Ground Movement Planning (Delivery) ............................................ 4-24 4.19.3.3. Ground Movement Control............................................................. 4-24 4.19.3.4. Departures.................................................................................. 4-24 4.19.4. Usage Scenario for Airport Frequencies – Arriving Aircraft.................. 4-25 4.19.4.1. Arrival ATIS ................................................................................ 4-25 4.19.4.2. Arrivals ...................................................................................... 4-25 4.19.4.3. Ground Movement Control............................................................. 4-25 4.20. Future Changes of the Reference UK Airspace .................................. 4-26

5. Airborne Users’ Topology................................................5-1 5.1. Air Traffic/ATC & CNS Simulation Tool (NAVSIM) ................................ 5-1 5.2. Airborne User Topology................................................................... 5-1 5.3. UK Airspace Implementation within NAVSIM ...................................... 5-2 5.4. ATC Statistics................................................................................ 5-4

6. Operational Aspects of VHF Voice Communications ............6-1 6.1. Introduction .................................................................................. 6-1 6.2. General Characteristics of Voice Communications ............................... 6-1 6.3. Classification of Voice Services......................................................... 6-2 6.3.1. Pilot-Controller Voice Services ......................................................... 6-6 6.3.2. Voice Broadcast Service.................................................................. 6-6 6.3.3. Pilot-Pilot Voice Service .................................................................. 6-6 6.3.4. Interactive Air-Ground Voice Service ................................................ 6-6 6.4. Medium Access for Voice Communications ......................................... 6-7 6.4.1. Party-line with PTT-based Channel Access ......................................... 6-7 6.4.2. Voice Delay and Signalling Delay...................................................... 6-7 6.5. Voice Communications System Architecture..................................... 6-10 6.6. Uplink Voice Monitoring ................................................................ 6-11 6.7. Best Signal Selection/Best Transmitter Selection .............................. 6-11 6.8. Wide Area Coverage..................................................................... 6-12 6.8.1. Offset Carrier Operation (CLIMAX).................................................. 6-12 6.8.2. Selective Transmitter Keying ......................................................... 6-14



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6.8.3. Combined Method ........................................................................ 6-15 6.9. Channel Coupling......................................................................... 6-15 6.9.1. Wide Area Coverage with Channel Coupling ..................................... 6-16 6.10. Frequency Handover .................................................................... 6-16 6.11. System Redundancy..................................................................... 6-17

7. Operational Aspects of VHF DL Communications ................7-1 7.1. Classification of Data Links and Data Link Services ............................. 7-1 7.1.1. ATS Data Link ............................................................................... 7-1 7.1.1.1. Pilot-Controller Exchanges............................................................... 7-3 7.1.1.2. Pilot-Pilot Dialog ............................................................................ 7-3 7.1.1.3. Flight Information Exchanges .......................................................... 7-3 7.1.1.4. ATM Exchanges ............................................................................. 7-3 7.1.1.5. Downlink of Aircraft Data ................................................................ 7-3 7.1.1.6. Ground to Air Surveillance Broadcast ................................................ 7-4 7.1.1.7. Air Surveillance Broadcast............................................................... 7-4 7.1.2. AOC Data Link............................................................................... 7-4 7.2. Network Technologies..................................................................... 7-6 7.2.1. ACARS ......................................................................................... 7-6 7.2.2. ATN ............................................................................................. 7-7 7.2.2.1. ATN Infrastructure ......................................................................... 7-8 7.2.3. Broadcast Data Link ..................................................................... 7-10 7.3. VHF DL Technologies .................................................................... 7-11 7.3.1. Channel Access with ACARS, VDL2 and VDL4 ................................... 7-11 7.3.2. VDL2 Data Link............................................................................ 7-12 7.3.3. VDL4 Data Link............................................................................ 7-12 7.4. Data Link Coverage in Europe........................................................ 7-13 7.4.1. Recommendation ......................................................................... 7-16

8. Voice Communications Profiles ........................................8-1 8.1. VOCALISE Major Findings................................................................ 8-1 8.1.1. Frequency occupancy rate............................................................... 8-1 8.1.2. Contact ........................................................................................ 8-2 8.1.3. Exchange...................................................................................... 8-2 8.1.4. Traffic density ............................................................................... 8-3



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8.1.5. Verbal acts ................................................................................... 8-3 8.1.6. Time of reaction ............................................................................ 8-3 8.1.7. Consolidated VOCALISE Results ....................................................... 8-3

9. Data Link Communications Profiles ..................................9-1 9.1. Message Volumes for ATS Services................................................... 9-1 9.2. Message Volumes for AOC Services .................................................. 9-6

10. Future Air Traffic Development......................................10-1 10.1. Introduction ................................................................................ 10-1 10.2. [EUROC_ADS] Brief Summary ....................................................... 10-1 10.3. Traffic Forecast 2015/2020/2025 ................................................... 10-6 10.4. Airborne User Topology (2015 - 2025) ............................................ 10-7 10.5. Equipage (2015 and 2020+).......................................................... 10-7 10.6. Specific Traffic Situation in the UK.................................................. 10-8 10.6.1. Implementation ........................................................................... 10-9 10.6.2. Technology ................................................................................. 10-9

11. Scenarios of Future Data Service Development................11-1 11.1. Estimation of Data Protocol Overhead ............................................. 11-1 11.2. ATS Data-Link Services................................................................. 11-1 11.2.1. European Scenario for 2015 [B-VHF D5] ......................................... 11-1 11.2.2. USA Scenario for 2015 [AATT_2015] .............................................. 11-6 11.2.2.1. Aircraft Classes and Domains......................................................... 11-6 11.2.2.2. Mapping of [AATT_2015] Messages onto CoS Classes........................ 11-7 11.2.2.3. ATS Data Link Scenario [AATT_2015] ............................................. 11-9 11.2.3. Comparison of ATS Scenarios .......................................................11-11 11.2.4. ATS Data Link Scenarios for 2020+ ...............................................11-14 11.3. AOC Data Link Services by 2015, 2020 and 2025 ............................11-16

12. Scenarios of Future Voice Service Development...............12-1 12.1. Required Cell Voice Capacity.......................................................... 12-1 12.1.1. CoS v1 ....................................................................................... 12-1 12.1.2. CoS v2 ....................................................................................... 12-2



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12.1.3. CoS v3 ....................................................................................... 12-2 12.1.4. CoS v4 ....................................................................................... 12-2 12.1.5. CoS v5 ....................................................................................... 12-2 12.1.6. CoS v-AOC.................................................................................. 12-2 12.2. Demand for Permanent Voice Circuits ............................................. 12-3 12.3. Demand for Temporary Voice Circuits ............................................. 12-4 12.4. Estimation of Voice Protocol Overhead ............................................ 12-7 12.5. Representative Voice Exchanges .................................................... 12-7 12.5.1. Standard Voice Exchange.............................................................. 12-8 12.5.2. Standard On-demand Exchange ..................................................... 12-8 12.5.3. Standard Broadcast Transmission................................................... 12-9 12.6. Voice Service Evolution................................................................. 12-9 12.7. Scenarios for the Year 2015, 2020 and 2025...................................12-11

13. Non-technical Aspects Affecting the B-VHF System ..........13-1 13.1. Single European Sky .................................................................... 13-1 13.2. Institutional Issues ...................................................................... 13-1 13.3. Shared Broadband Technology....................................................... 13-2 13.4. Preserving Investments ................................................................ 13-3 13.5. Information Management .............................................................. 13-4 13.6. Security...................................................................................... 13-4 13.7. Safety Aspects of Integrated Voice-Data Systems............................. 13-5

14. Conclusions ................................................................14-1

15. References .................................................................15-1

16. Abbreviations .............................................................16-1

Illustrations

Figure 1-1: B-VHF Project Work Breakdown Structure Overview............................... 1-3 Figure 4-1: UK Flight Information Regions ............................................................ 4-2 Figure 4-2: Diagram showing Airways in UK airspace.............................................. 4-3



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Figure 4-3: Vertical division of airspace ................................................................ 4-4 Figure 4-4: UK airspace classification ................................................................... 4-6 Figure 4-5: Separation Minima (RVSM)................................................................. 4-6 Figure 4-6: LACC Sectorisation............................................................................ 4-8 Figure 4-7: Holding Stack in Terminal Control Area ................................................ 4-9 Figure 4-8: LTCC Sectors (excluding TC Capital) .................................................... 4-9 Figure 4-9: LTCC TC Capital.............................................................................. 4-10 Figure 4-10: LTCC TC North/South Airspace Boundaries........................................ 4-10 Figure 4-11: MACC Sectorisation ....................................................................... 4-11 Figure 4-12: Scottish General Sectorisation (Low)................................................ 4-12 Figure 4-13: Scottish General Sectorisation (High) ............................................... 4-13 Figure 4-14: Predicted Area coverage - Moray Sector at 10,000 ft (amsl) ................ 4-16 Figure 4-15: Predicted Duplicate coverage - TC NW DEPS Sector at 3,000 ft (amsl) .. 4-17 Figure 4-16: Multi-Carrier Transmit Overview...................................................... 4-18 Figure 4-17: Multi-Carrier Receive Overview ....................................................... 4-19 Figure 4-18: GMC Split at Heathrow (reproduced by kind permission of BAA plc) ...... 4-23 Figure 4-19: ATC Frequency Usage in a Departure Scenario .................................. 4-25 Figure 4-20: ATC Frequency Usage in an Arrival Scenario...................................... 4-25 Figure 5-1: NAVSIM Implementation of UK Airspace............................................... 5-3 Figure 5-2: NAVSIM Implementation of UK ATC Sectors.......................................... 5-3 Figure 5-3: European Core Area around Brussels (EBBR) ........................................ 5-6 Figure 5-4: Reference area around London Heathrow (EGLL) ................................... 5-6 Figure 5-5: Reference area around Frankfurt (EDDF).............................................. 5-7 Figure 5-6: ATC Statistics for range 200 nm around Brussels (EBBR) ........................ 5-8 Figure 5-7: Detailed ATC Statistics for 200 nm range around Brussels (EBBR)............ 5-8 Figure 5-8: Detailed ATC Statistics for 200 nm range around Brussels (EBBR)............ 5-9 Figure 6-1: MACONDO Voice Service Types........................................................... 6-4 Figure 6-2: Voice Communications Session ........................................................... 6-9 Figure 6-3: VCS Architecture ............................................................................ 6-10 Figure 6-4: CLIMAX Allocations in Europe ........................................................... 6-13 Figure 6-5: Offset-carrier Uplink Signal with Four Legs ......................................... 6-13 Figure 6-6: Offset-carrier (CLIMAX) Operation with Three Legs .............................. 6-14 Figure 6-7: Coupling With Re-transmission ......................................................... 6-16 Figure 7-1: Representative DLH AOC Data Link Profile ............................................ 7-4 Figure 7-2: Representative SAS AOC Data link Profile ............................................. 7-5



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Figure 7-3: End-to-end ACARS Data Link Architecture ............................................ 7-7 Figure 7-4: ATN Protocol Stack............................................................................ 7-8 Figure 7-5: ATN Architecture ............................................................................ 7-10 Figure 7-6: VDL4 Ground Infrastructure ............................................................. 7-11 Figure 7-7: ARINC ACARS Coverage in Europe..................................................... 7-14 Figure 7-8: SITA ACARS Base Frequency Coverage in Europe ................................ 7-14 Figure 7-9: ARINC VDL2 Coverage in Europe....................................................... 7-15 Figure 7-10: SITA VDL2 Coverage in Europe ....................................................... 7-15 Figure 7-11: VDL4 Coverage............................................................................. 7-16 Figure 8-1: Structure of a Voice Session (VOCALISE) ............................................. 8-2 Figure 10-1: Reference [EUROC_ADS] Airspace ................................................... 10-3 Figure 10-2: European Core Area and non-Core Area HZs [EUROC_ADS] ................ 10-4 Figure 10-3: TMA Traffic Forecast to 2017 .......................................................... 10-8 Figure 10-4: UK Movements ............................................................................. 10-8 Figure 12-1: Standard Voice Exchange ............................................................... 12-8 Figure 12-2: Standard On-demand Exchange ...................................................... 12-8 Figure 12-3: Sample Voice Scenario (AP, TMA, ENR) ...........................................12-14

Tables

Table 4-1: Offset-carrier Operation .................................................................... 4-18 Table 4-2: Service allocation of Heathrow VHF assignments .................................. 4-21 Table 4-3: Summary of Heathrow ATIS service allocation...................................... 4-22 Table 4-4: Airport Development in the UK........................................................... 4-26 Table 5-1: ATC Airspace Statistics for Brussels Area (EBBR) .................................. 5-11 Table 5-2: ATC Airspace Statistics for London Area (EGLL) .................................... 5-12 Table 5-3: ATC Airspace Statistics for Frankfurt Area (EDDF)................................. 5-13 Table 6-1: Voice Service Classes and Connectivity ................................................. 6-4 Table 6-2: Today’s Operational Voice Service Types ............................................... 6-5 Table 7-1: Data Link Service Classes and Connectivity............................................ 7-2 Table 8-1: Summary of VOCALISE Voice Statistics ................................................. 8-4 Table 9-1: Total ATS Uplink/Downlink Traffic......................................................... 9-2 Table 9-2: DLIC Data Volume Exchanged per FIR................................................... 9-3 Table 9-3: FLIPCY Data Volume Exchanged per FIR................................................ 9-3 Table 9-4: ATIS Data Volume Exchanged with Departure FIR................................... 9-3



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Table 9-5: ATIS Data Volume Exchanged with Arrival FIR........................................ 9-3 Table 9-6: DCL Data Volume Exchanged with Departure FIR.................................... 9-4 Table 9-7: ACM Data Volume Exc. with Current ACC (Internal Transfer) .................... 9-4 Table 9-8: ACM Data Volume Exc. with Current ACC (Transfer to Other FIR).............. 9-4 Table 9-9: ACM Data Volume Exc. with Next ACC (Transfer to Other FIR).................. 9-4 Table 9-10: ACL Data Volume Exchanged per FIR – Scenario 1 ................................ 9-5 Table 9-11: ACL Data Volume Exchanged per FIR – Scenario 2 ................................ 9-5 Table 9-12: ACL Data Volume Exchanged per FIR – Scenario 3 ................................ 9-5 Table 9-13: CAP Data Volume Exchanged – Periodic Contract .................................. 9-5 Table 9-14: CAP Data Volume Exchanged – Event Contract ..................................... 9-6 Table 9-15: Total AOC Per-flight Data Volume ....................................................... 9-6 Table 10-1: [EUROC_ADS] Parameters............................................................... 10-2 Table 10-2: Number of A/C vs. Distance from Brussels ......................................... 10-5 Table 11-1: Data Link Scenarios (2015) from [B-VHF D5] ..................................... 11-5 Table 11-2: Aircraft Classes [AATT_2015, Table 4.1-3] ......................................... 11-6 Table 11-3: Mapping of [AATT_2015] Domains to [B-VHF D5] HZs ......................... 11-6 Table 11-4: Aircraft Equipage Levels [AATT_2015, Table 4.1-4] ............................. 11-7 Table 11-5: [AATT_2015] Message Mapping onto [B-VHF D5] CoS Classes .............. 11-8 Table 11-6: Class 3 Data Link Profile - [AATT_2015] Table 4.3-5............................ 11-9 Table 11-7: Data Link Profiles and Requirements from [AATT_2015]......................11-12 Table 11-8: Summary of [B-VHF D5] and [AATT_2015] Data Link Requirements .....11-13 Table 11-9: 2020/2025 ATS Scenarios Based on [AATT_2015] and [B-VHF D5].......11-15 Table 11-10: [B-VHF D5] AOC DL Scenario ........................................................11-17 Table 11-11: [B-VHF D5] AOC Data Volumes for the Year 2005 ............................11-18 Table 11-12: AOC Data Volumes for the years 2015 [AATT_2015].........................11-19 Table 11-13: AOC forecasts for the years 2015, 2020 and 2025............................11-19 Table 12-1: Voice Service Users within the B-VHF Cell .......................................... 12-1 Table 12-2: Currently Allocated Voice Circuits for Different Airport Types ................ 12-3 Table 12-3: Aerodromes and CTR Statistics for Core Area ..................................... 12-5 Table 12-4: Aircraft Statistics for Core Area ........................................................ 12-6 Table 12-5: ATC Voice Statistic Parameters......................................................... 12-7 Table 12-6: Currently Allocated Voice Circuits for Different Airport Types ...............12-10 Table 12-7: Voice Service Evolution ..................................................................12-12



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1. Introduction

1.1. B-VHF Project Description

Air transport has been identified as a dominant factor for sustainable economic growth of the European Union. The "Vision 2020" clearly points out the cornerstones of a future air transport system and the Advisory Council for ATM Research in Europe (ACARE) elaborates these requirements in depth in their "Strategic Research Agenda".

A/G communication is the key enabler for achieving an Air Transport System that is capable of meeting future demands. The communications in the VHF aeronautical communications (COM) band (118 - 137 MHz) are particularly attractive as they provide adequate coverage with moderate equipment power and acceptable price.

Today, an analogue VHF voice communications system is still used for tactical aircraft separation and guidance. This communications technology has been introduced in the '40s and generally utilises the available VHF spectrum in an inefficient and inflexible manner. A small part of the COM spectrum is used by several types of aeronautical data links (ACARS, VDL Mode 2, and VDL Mode 4) for safety-related data link communications.

After 2010, the VHF COM band in Europe is expected to become progressively saturated. This is expected to happen in spite of the recent introduction of the 8.33 kHz DSB-AM voice system and the VDL Mode 2 data link that both use the VHF spectrum in a more efficient manner than the "old" solutions. The main reason for the saturation is the traditional ATM operational concept based on the tactical control of aircraft that generates increased demand for voice communications channels proportional to the increase in air traffic itself.

The problem can only be solved by adopting new ATM concepts. Strategic European documents and recent studies indicate that a relief after 2010 may be achievable with intensive usage of the aeronautical data link. The tactical Air Traffic Control (ATC) will shift towards strategic Air Traffic Management (ATM), and at the same time the demand for new VHF voice communications channels would be reduced.

Today’s VHF solutions – including VDL Mode 2 data link - cannot fulfil performance and capacity requirements of future data link applications.

As there are no plans to deploy VDL Mode 3 system in Europe, VDL Mode 4 remains as only European option to replace VDL Mode 2 data link in the future. VDL Mode 4 as a pure data link technology without support for voice communications is capable to solve only a part of the congestion problem. In order to provide expected data link capacity, VDL Mode 4 would require multiple VHF channels that are difficult to find and co-ordinate. As there are still some unresolved architectural issues, there is no guarantee that VDL Mode 4 airborne radio can be operated without interference with analogue VHF voice radios.

EUROCONTROL’s Communications Strategy clearly points out the need for alternative communications systems. Air Traffic Service Providers (ATSPs) prefer keep on using their existing ground communications facilities, so an integrated voice-data system in the VHF range would be highly appreciated, being capable of using same physical locations of ground stations and same interconnecting infrastructure as the current VHF system. Therefore, more and more attention in Europe is directed towards broadband VHF technologies.




Within the course of the B-VHF project bottom up research on multi-carrier technology (MC) for aeronautical communications is carried out. This work will result in the definition of a new future MC broadband VHF (B-VHF) system, which is able to support Single European Sky, Free Flight and other advanced concepts and programmes, leading far beyond 2015 into Vision 2020. The B-VHF project is conducted under Priority #4/ Aeronautics and Space of the Sixth Framework Programme (FP6) of the European Commission (EC).

The target technology is MC-CDMA, a highly innovative, high capacity technology that is also discussed for fourth generation (4G) mobile communications systems. However, the project will investigate possible implementation outside the VHF range, as well as non-CDMA access schemes.

The B-VHF system has the potential to exploit the mobile VHF aeronautical channel better than any currently discussed VHF communication alternative. It increases voice and data capacity and addresses security and safety issues, promising a service level that is today unknown to the aeronautics user. Moreover, it has the potential to preserve the excellent inherent cost-range characteristics of the VHF band. It may eventually be applied as an overlay system and co-exist with the available VHF infrastructure, providing smooth transition and rollout scenarios.

The proposed B-VHF system will support both voice and data link communications. The main expected benefits of the future B-VHF communications system are:

High spectral efficiency - the broadband B-VHF system uses VHF spectral resources more efficiently than today's narrowband VHF communications systems

High communication capacity - the total capacity of the B-VHF system is higher than the aggregate capacity of VHF systems deployed today or planned for a near future

Flexibility - the B-VHF system may be easily adapted to provide support for new operational and communications requirements

Security - the B-VHF system is inherently resistant against narrowband jamming and provides mechanisms supporting end-to-end data security

Sound transition path - the B-VHF system uses the knowledge about the current usage of VHF spectrum and may be able to share the VHF spectrum with legacy narrowband VHF systems without adverse interfering effects

1.2. B-VHF Project Work Breakdown

The high-level goal of the B-VHF project - proving the feasibility of the broadband MC-CDMA technology and demonstrating its benefits to the aeronautical community - requires a series of interrelated tasks that have been encapsulated as five separate workpackages in the B-VHF project:

WP 0 – "Project Management and Quality Assurance"

WP 1 – "B-VHF System Aspects"

WP 2 – "VHF Band Compatibility Aspects"

WP 3 – "B-VHF Design and Evaluation"

WP 4 – "B-VHF Testbed"




Figure 1-1 summarises the detailed work breakdown of the B-VHF project, including main work packages and all sub-work packages:

Research, technologicaldevelopment and innovation

ProjectManagement

WP 1B-VHFSystemAspects

WP 2VHF BandCompatibilityAspects

WP 3B-VHFDesign andEvaluation

WP 1.1B-VHFOperationalConcept

WP 1.2ReferenceEnvironment

WP 1.3B-VHFDeploymentScenario

WP 2.1Theoretical VHFBandCompatibilityStudy

WP 2.2VHF ChannelOccupancyMeasur.

WP 2.3InterferenceModelling

WP 3.2PHY LayerDesign & SWImplementation

WP 3.3DLL LayerDesign & SWImplementation

WP 3.5B-VHFEvaluation

WP 3.4Protocol Design& SWImplementation

WP 0ProjectManagementand QualityAssurance

WP 0.1ProjectManagement

WP 0.2Validation andQM

WP 0.3KnowledgeManagement

WP 3.1VHF ChannelModelling

WP 4B-VHFTestbed

WP 4.1BasebandImplementation

WP 4.2VHF FrontendDevelopment

WP 4.3B-VHF TestbedEvaluation

Figure 1-1: B-VHF Project Work Breakdown Structure Overview

WP 0 "Project Management and Quality Assurance" comprises all activities that are essential to all work packages. It takes care of achieving high quality results throughout the whole project. It covers all management activities on Consortium level, in particular the information exchange and co-ordination with the European Commission and with the partners. A separate sub-work package has been destined for the validation and quality control which reflects the importance of maintaining high quality outputs in all project phases. Another sub-work package is dedicated to manage new knowledge generated within the B-VHF project in terms of intellectual property rights and dissemination strategies.

WP 1 "B-VHF System Aspects" establishes the necessary connection between the scope and goals of the B-VHF project and the high-level objectives of the EC, European and global aeronautical community. Starting at the very beginning of the B-VHF project, this work package will produce high-level requirements for the B-VHF system, describe the reference aeronautical environment and produce the B-VHF Operational Concept document. By the end of the B-VHF project, the WP 1 will produce the B-VHF Deployment Scenario document, describing technological, operational and institutional issues of the B-VHF initial deployment, transition and operational usage.




WP 2 "VHF Band Compatibility Aspects" assesses by theoretical (modelling) and practical (measurements) means probably the most critical aspect of the future B-VHF broadband channel: its capability to be installed and operated "in parallel" with legacy narrowband channels, sharing the same part of the VHF spectrum, but remaining robust against interference coming from such legacy narrowband VHF systems. The investigations will also address the conditions for interference-free operation of the B-VHF system towards legacy narrowband VHF systems. The Theoretical VHF Band Compatibility Study developed in the WP 2 will provide inputs to the WP 1 required for the development of the B-VHF Deployment Scenario. Together with the B-VHF Interference Model developed in the WP 2, the Theoretical VHF Band Compatibility Study will also be used as input for the B-VHF system design and evaluation (WP 3).

WP 3 "B-VHF Design and Evaluation" covers B-VHF system design tasks, starting with developing the model of the broadband VHF channel, and proceeding with the development and implementation of the SW representing the physical (PHY) B-VHF layer, DLL layer, higher protocol layers and representative aeronautical applications. The design and implementation tasks will be augmented by the development of detailed evaluation plans and corresponding simulation scenarios. The B-VHF Evaluation Reports produced in the WP 3 will provide necessary feedback to the B-VHF Deployment Scenario task of the WP 1. The WP 3 will also produce as a deliverable a complete set of the B-VHF System Design and Specification documents.

The prime objective of the B-VHF project - demonstrating the capabilities of the MC-CDMA technology - will be achieved within the scope of the WP 3 by using intensive and layered simulation trials. This task will start with investigating the capabilities and performance of the B-VHF physical layer and will proceed by adding/integrating the DLL and upper protocol layers, respectively. The "generic" B-VHF technology validation will be concluded by considering specific requirements coming from the aeronautical environment and applications. The WP 3 will develop and implement a SW set of representative communications applications and verifies by simulation means that the B-VHF system can support a mix of such applications under nearly-realistic loading, while fulfilling the Quality of Service (QoS) and other requirements of each particular application.

WP 4 "B-VHF Testbed" covers the baseband implementation and evaluation of a first B-VHF testbed for both the forward- and the reverse-link. The implementation is carried out in DSP technology and is restricted to the physical layer, which is the most critical part of the B-VHF development. The B-VHF baseband implementation is interfaced to the low-power broadband VHF frontend, thus, enabling testbed evaluation not only in the baseband but also in the VHF band. Testbed evaluation in the baseband is performed using channel and interference models, which are also implemented in DSP technology. The VHF band evaluation is carried out in the laboratory using actual VHF systems as interference sources and victim receivers, respectively.

----------- END OF SECTION -----------




2. Executive Summary

The B-VHF project develops and validates basic functional principles and architecture of completely new VHF communications sub-network technology, capable to support both current aeronautical communications needs and estimated future demands.

The project deliverable D5 entitled «Report on Applications Communications Requirements» defines high-level functional and performance requirements for the B-VHF communications technology. These requirements are derived from a set of selected reference documents. Being a requirements document, D5 just specifies necessary functional and performance aspects of a new system, but does not describe in detail the operational environment in which such a system should be used.

Project deliverable D8 «B-VHF Reference Environment» addresses baseline information required for designing the B-VHF system. It “sets up the scene” for the B-VHF system deployment by providing supplementary information, which has not already been covered by the deliverable D5.

Additionally, it provides information necessary for B-VHF interference modelling, development of B-VHF Operational Concept, and for subsequent system performance evaluation conducted within the WP 3 of the B-VHF project.

The information provided in the B-VHF Reference Environment document (D8) includes:

Rationale for the selection of the B-VHF reference airspace

Information about the UK airspace, including airspace classification and structure, ATC sectors, airspace rules, separation standards and description of different types of ATC facilities operating within the UK airspace

Description of existing NERL voice radio communications system, associated operational requirements, frequency planning criteria, Multi-carrier (CLIMAX) operations, radio functions and regulatory issues

Basic characteristics of the NERL VHF ground stations, including radio station configuration and coverage

Information about the number of VHF frequencies at a large UK airport (Heathrow), including the detailed frequency allocations, as well as scenarios of operational usage

Information about planned changes of the UK airspace structure in the future

Brief description of the ATC & CNS Simulation Tool NAVSIM used for the VHF channel occupancy modelling, interference modelling and B-VHF system capacity/performance modelling and simulation

List of reference sources with respect to the airborne users’ topology within the reference airspace

Explanation of a general modelling approach when implementing reference airspace(s) within the NAVSIM tool and generating representative airborne pictures

Number of airports, aircraft, ATC sectors found within a given distance from several selected locations within European Core Area (Brussels, London, Frankfurt), aircraft entry time and dwell time statistics within an ATC sector and further detailed ATC statistics, to be used for dimensioning the B-VHF system

General characteristics and classification of existing and future ATS voice services, analysis of the medium access to the voice radio channel, voice and signalling




delay, description of basic voice system architecture, explanation of specific ATC features like monitoring of uplink voice, best signal selection, wide area coverage and coupling of voice channels

ATS data link service classification, sample profiles for AOC data link, description of ACARS, ATN and broadcast data links and associated network architectures, brief survey of existing VDL2 and VDL4 data link technologies and basic information about data link coverage in Europe

Summary of the French VOCALISE study, describing representative ATC voice communications profiles in the high-density en-route airspace

Description of baseline ATS and AOC data link communications profiles as applicable today in the representative European airspace

Scenarios of future development of air traffic over European Core Area, aligned with B-VHF deliverable D5 and [MACONDO] scenarios for the year 2015 and including hypotheses for the air traffic development beyond 2015 (for the years 2020 and 2025, respectively)

Scenarios of future evolution of VHF data link services, aligned with B-VHF requirements addressed in deliverable D5, supplemented by the USA scenarios based on [AATT_2015], including hypotheses for the data link service usage for the years 2015, 2020 and 2025, respectively

Specific requirements of existing and future voice services, estimate of demand for permanent and temporary voice circuits, representative voice exchange profiles, scenarios of future evolution of VHF voice services, aligned with requirements listed in B-VHF deliverable D5 and including hypotheses for the voice service usage for the years 2015, 2020 and 2025, respectively

Selected non-technical aspects affecting the deployment of a future VHF communications system

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3. Scope

Project deliverable D8 «B-VHF Reference Environment» addresses baseline information required for designing the B-VHF system. It “sets up the scene” for the B-VHF system deployment by providing supplementary information which has not been covered by the deliverable D5. Additionally, it provides information necessary for B-VHF interference modelling, development of B-VHF Operational Concept and system performance evaluation within the WP 3 of the B-VHF project.

The B-VHF Reference Environment document (D8) is organised as follows:

Chapter 1 – Introduction - provides a brief description of the B-VHF project.

Chapter 2 – Executive summary – provides a high-level overview of the D8 document.

Chapter 3 – Scope - (this chapter) explains the scope and structure of the D8 document.

Chapter 4 – Reference Airspace - provides information about the UK airspace structure, technical details of NERL’s radio system, as well as descriptions of voice operational practices in an En-route, TMA and airport environment.

Chapter 5 – Airborne Users’ Topology - contains the description of the NAVSIM simulation, a general approach for the implementation of the air picture for the interference modelling and the ATC statistical data for selected regions in Core Europe.

Chapter 6 – Operational Aspects of VHF Voice Communications - describes operational aspects related to the VHF voice system, supplementing the UK-specific information provided in the Chapter 4.

Chapter 7 – Operational Aspects of VHF DL Communications - describes operational and technical aspects of currently existing VHF data links and associated data networks.

Chapter 8 – Voice Communications Profiles - provides initial estimates of “per aircraft” voice communications profiles, based on the French VOCALISE study.

Chapter 9 - Data Link Communications Profiles – contains a description of baseline ATS and AOC data link communications profiles as applicable today in the representative European airspace.

Chapter 10 – Future Air Traffic Development - describes scenarios of future development of air traffic over European Core Area for the years 2015, 2020 and 2025, respectively.

Chapter 11 – Scenarios of Future Data Service Development - provides scenarios of future evolution of VHF data link services for the years 2015, 2020 and 2025, respectively.

Chapter 12 – Scenarios of Future Voice Service Development - provides scenarios of future evolution of VHF voice services for the years 2015, 2020 and 2025, respectively.

Chapter 13 – Non-technical Aspects Affecting the B-VHF System – addresses selected non-technical aspects affecting the deployment of a future VHF communications system.

Chapter 14 – Conclusions – briefly summarizes the D8 document.




Chapter 15 – References – lists external documents and other references used for producing the D8 document.

Chapter 16 – Abbreviations – is a list of abbreviations used throughout the D8 document.

----------- END OF SECTION -----------




4. Reference Airspace

This section provides rationale for the selection of the B-VHF reference airspace, as well as the detailed information about UK airspace classification and structure, airspace rules, separation standards and different types of ATC facilities operating within the UK airspace. Further it describes NERL voice radio system, associated operational requirements, frequency planning criteria and regulatory issues, and provides basic characteristics of the VHF ground stations, including radio station configuration and coverage.

4.1. Rationale for the Reference Airspace Selection

The selection of the reference environment for the B-VHF project was guided by the opportunities to obtain detailed data about the airspace configuration, description of operational airspace usage and to perform practical VHF occupancy measurements.

The B-VHF project members decided to select the UK airspace as reference environment for the B-VHF measurements and performance simulation for the following reasons:

NERL as a major Air Traffic Service Provider (ATSP) has indicated at the beginning of the B-VHF project the readiness to provide necessary data to the B-VHF project members.

NERL was deeply involved with the preparation and conduction of the measurement campaign.

Significant part of the UK airspace belongs to the European Core Area which has the most demanding requirements with respect to B-VHF communications services.

London TMA and associated En-route airspace represents the busiest spot in the whole European Core Area and has been used as a representative busy TMA airspace for the EUROCONTROL Operational Concept of mobile communications [MACONDO].

NOTE: NERL provides the B-VHF Consortium with detailed information about the frequencies/locations of UK En-route/TMA ground stations that supplements descriptive information provided in this section [NERL_GS]. The database allows for unique association of the Ground Stations (GS) and ATC sector(s). Additionally it is possible to identify GSs using offset-carrier operation. Further information about European GSs – including the UK-ones - has been provided to the B-VHF Consortium by the EUROCONTROL [EUROC_VHF].

NOTE: For some simulation tasks, e.g. obtaining representative ATC statistics (chapter 5 of this document) the reference airspace has been extended to the European Core Area of 200 nm around Brussels.

4.2. United Kingdom - Division of Airspace

The United Kingdom airspace is divided into two Flight Information Regions (FIRs). In addition, the Scottish and Oceanic Area Control Centre (ScOACC) at Prestwick provides Air Traffic Services across the North Atlantic (NAT) Region. ScOACC has responsibility for the Oceanic Control Area to 30°W (Figure 4-1).

Within each FIR the airspace below Flight Level 245 is known as a lower flight information region and that above FL245 as an upper flight information region.




Within the Flight Information Regions, airspace is described as controlled or uncontrolled, with further classifications describing the Air Traffic Control (ATC) service and minimum aircraft equipment required to operate in that airspace.

Figure 4-1: UK Flight Information Regions

4.3. Controlled Airspace

The guiding principle of Air Traffic Control is that safety is paramount. Controllers must therefore keep the aircraft they handle safely separated using internationally agreed standards. These separation standards are described in terms of horizontal or vertical minima. For example, aircraft flying in Controlled Airspace under radar surveillance are kept at least 5 nm apart horizontally or at least 1,000 ft vertically.

Within the airspace, a network of corridors, known as airways, has been established. These airways are usually 10 miles wide and extend up to a height of 24,000 ft from a base of around 5,000 to 7,000 ft. They mainly link busy areas of airspace known as Terminal Manoeuvring Areas (TMA) which are normally located above major airports




(Figure 4-2). At a lower level, control zones are established around each airport to protect arriving and departing aircraft during their climb and descent phases of flight (Figure 4-4).

Figure 4-2: Diagram showing Airways in UK airspace

Within these areas of ‘controlled airspace’, pilots must comply with ATC instructions. Outside controlled airspace pilots are responsible for their own safety and separation, although they can request assistance. Military controllers, who work closely with their civilian colleagues to provide a fully integrated service to all users, offer an air traffic service to aircraft in uncontrolled airspace. Military personnel also provide services to aircraft crossing airways and for those flying above 24,500 ft.

Aircraft in the final descent or initial climb stages of their journeys are managed by ATC at the airport itself. When aircraft join the airway system, responsibility for handling them, passes to controllers working at the appropriate Area Control Centre (ACC). A flight through an individual ACC’s airspace could pass through several ‘sectors’ of airspace, each managed by a different team of controllers.

The classifications of controlled airspace are described in more detail in the following paragraphs.




Figure 4-3: Vertical division of airspace

Airways and certain Control Zones / Areas (Class ‘A’)

Aircraft using Class ‘A’ airspace must have ATC permission and comply with ATC instructions so that controllers can provide a safe and efficient service. Any aircraft wishing to cross airways may do so either under the control of civil ATC or of a military controller working in liaison with the civil controller. Airways cross national boundaries and are identified by a letter/number code; for example, Alpha One (A1), Romeo One Five (R15) etc. Aircraft follow these routes using VOR/DME and the routes interconnect just as roads do. As an example Airway Alpha One (A1) starts at Glasgow, runs down to Worthing on the south coast of the UK, then crosses France, routes to the west of Italy and across the Mediterranean. It can be joined by aircraft at any point, or left to join another intersecting airway.

Upper Airspace (Class ‘B’)

Above 24,500 ft all traffic is subject to full and mandatory radar control either by civil or military units. Civil A/C follow Upper Air Routes which avoid areas of intensive military flying.

Control Zone (Class ‘D’)

Controlled airspace established around an airport extends from ground level upwards. It protects aircraft during the take off and landing phase of the flight and ensures that all aircraft in the vicinity of an airport are known to controllers, who can then provide a safe ATC service. A zone may also include helicopter routes or corridors for access to and from small airfields within the zone but these will always be planned in such a way that aircraft using them will remain clear of traffic using the main airport.

Control Area (Class ‘D’)

A Control Area is established between the airfield Control Zone and the Airways route structure to provide a controlled airspace environment between the airfield and the en-route phase of the flight. It also provides safe, known environment in which holding stacks can be established.




Class ‘E’

This is not a completely ‘known’ environment to ATC in that IFR aircraft will have filed flight plans and those using VFR may not. The airspace is therefore slightly less restrictive to pilots, but ATC can only provide certain information i.e. they do not know the intentions of VFR aircraft. Certain Control Zones and Areas within the U.K. have been given a Class ‘E’ classification.

4.4. Uncontrolled Airspace

Outside controlled airspace aircraft may fly without ATC permission, with the exception of aerodrome operations. Pilots are free to choose whether to fly within controlled airspace or outside it. However, outside controlled airspace, certain ATC services are still available as follows:

Advisory Routes (Class ‘F’)

ATC notifies a small number of preferred routes outside controlled airspace known as ‘Advisory Routes’. These are not busy enough to justify airway status but are useful from time to time and they are published so that all airspace users are aware of them. A pilot wishing to use such a route will be given an ATC service to ensure their separation and a pilot wishing to cross an advisory route can call the controlling authority to ask for details of any activity on it.

Class ‘G’

Uncontrolled airspace below 24,500 ft, a flight information service, providing information on any known traffic, can be provided if requested.

Lower Airspace Radar Service

Below 9,500 ft certain co-opted Ministry of Defence (MOD) units provide a Lower Airspace Radar Service. This service supplements NATS services and is available to all A/C flying between 3,000 ft above mean sea level and Flight Level 95 (FL95), within approximately 30 nautical miles of each listed aerodrome.

4.5. Airspace Rules

Classes A, B, D, and E are ‘Controlled Airspace’. Classes F and G are not controlled, although Advisory or Information services are normally available;

Flights under Visual Flight Rules (VFR) are not permitted in Class A airspace;

Flights operating in Class D, E, F and G below FL100 are all subject to a maximum speed limit of 250 knots;

Radio equipment is not mandatory in Classes F and G, nor in Class E when under VFR (Visual Flight Rules).

Figure 4-4 provides an overview of the general classification of UK airspace.




Figure 4-4: UK airspace classification

4.6. Separation Standards

UK airspace is frequently congested, especially at peak hours, with a high proportion of the traffic either climbing or descending. The controller’s task is to ensure that flights are able to operate speedily and economically, with due regard for safety.

Figure 4-5: Separation Minima (RVSM)




The controller must at all times keep aircraft apart by prescribed limits. Flights under radar control are not permitted to pass within five miles of each other if at the same height. This distance may only be reduced if the two aircraft are at least 1,000 ft apart vertically, up to 29,000 ft. Above 29,000 ft, the vertical separation required is increased to 2,000 ft (except between suitably equipped RVSM aircraft where 1,000 ft is applicable between FL290 and FL410). In addition, depending on the heading of the aircraft, cruising levels are allocated in accordance with the ‘semicircular rule’, using ICAO semicircular standard cruising levels. However, ATC are able to authorise flight levels that do not comply with the rule.

Height separation minima 1,000 ft (2,000 ft in non-RVSM airspace)

Lateral separation minima 5 nm (3 nm in London TMA)

4.7. Control of Airspace in the United Kingdom

Aerodrome Control

Air Traffic Control at aerodromes essentially consists of two major functions:

a) Ground movement control;

b) Arrival and Departure Control.

Once outside of the Aerodrome Control Area, aircraft using controlled airspace are transferred to the Air Traffic Control Centre responsible for that airspace.

London Area Control Centre (LACC)

The prime responsibility of the London Area Control Centre (LACC) is to provide air traffic services to aircraft flying in Control Areas (Airways) and on Upper Air Routes (UARs), except within the defined areas of responsibility of London Terminal Control Centre (LTCC) or Manchester Area Control Centre (MACC). Figure 4-6 describes the LACC airspace sector organisation. Sectors are created to take account of dominant flows and contain ATC workload at a manageable level. Aircraft flying in the London Terminal Manoeuvring Area (LTMA) receive an air traffic control service from the LTCC.




S14 235-295S13 295-660

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LACC SECTORISATION 24.12.03

BCN (5, 8, 23)BHD (6, 9)

WOR (18, 19, 20, 21)

CLN (12, 13, 14)DTY (27, 28, 32, 34)DVR (15, 16, 17)LKS (3, 4, 7)LMS (25, 26)LUS (1, 2)NOR (10, 11)

SECTORGROUPINGS

CHANGE: CLACTON RE-SECTORISATION.

COPIES OF THIS MAP ARE AVAILABLE FROM: OPERATIONAL INFORMATION, ROOM 3322, BOX 12, SWANWICK. \\CAHSWNS01\SWANWICK.GLB$\ATC\LACC SECTORISATION (WITH LEVELS).PDF

EFFECTIVE: 18 MARCH 2004

NOT FOR OPERATIONAL USE

Figure 4-6: LACC Sectorisation

London Terminal Control Centre (LTCC)

The prime responsibility of Terminal Control (TC) is to provide air traffic services to aircraft flying in the London TMA, surrounding airways and control areas, the London Control Zone, Gatwick Control Zone and Control Area, Stansted Control Zone and Control Area and the Luton Control Zone and Control Area.

London TMA Operation

The TMA controllers are responsible for aircraft flying at 21,500 ft and below, and handle traffic to and from airfields in the South East of the UK, as well as overflying aircraft.

Soon after take-off, departing aircraft are transferred to the TMA controllers who guide them around and through the routes of arriving A/C, onto the airways where they are handed over to en-route controllers.

Arriving aircraft are transferred from en-route to TMA controllers who then separate them from departing aircraft and direct them towards one of the London holding stacks. As they descend in the stacks they are released in sequence to the approach controllers at the destination airfield. In the case of Heathrow, Gatwick and Stansted, these controllers are sitting alongside the TMA controllers, which makes it easier to agree the order in which the A/C will leave the stacks.

The approach controllers then manoeuvre the aircraft as they leave the stacks, arranging them in sequence and ensuring there are no wasted spaces, so that the best use is made of the busy airport runways. A few minutes from touchdown, when they are lined up on their approach to the runway, arriving aircraft are transferred to the airport control tower for landing.




FL100

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Aircraft instructedto hold beforefinal approach

Aircraft descendin stack under controlof approach controller

Aircraft leave stackunder control of approach radar director

Aircraft transferred toaerodrome control VOR

Aircraft are transferredto approach controlat different levels

Control by ATCC

Runway

Transition Altitude

Figure 4-7: Holding Stack in Terminal Control Area

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TC AREA OF RESPONSIBILITY(EXCLUDING TC CAPITAL)

Figure 4-8: LTCC Sectors (excluding TC Capital)




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Figure 4-9: LTCC TC Capital

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TC NORTH / TC SOUTH TO FL175 TC SE LOW FL70- (DELEGATED BY CLACTON)

Figure 4-10: LTCC TC North/South Airspace Boundaries




Manchester Area Control Centre (MACC)

An area of Controlled Airspace (CAS) and Advisory Airspace within the London Flight Information Region (FIR) is allocated to the Manchester Area Control Centre (MACC).

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Figure 4-11: MACC Sectorisation

Scottish and Oceanic Area Control Centre (ScOACC)

ScOACC has responsibility for Air Traffic Control within the Scottish FIR and the Shanwick area of the North Atlantic Region (NAT).




DELEGATED TO AMSTERDAMFL175-FL245

UL10-UB6BUFFERDELEGATED FROM

MACC IOMFL165-FL245

DEL TO ABERDEEN

DEL TO ABERDEEN

NORTH SEA HIGH AREACOPENHAGEN ATSFL195 AND ABOVE

DELEGATED FROM SHANNON ACCFL245 - FL255

DELEGATED FROM MACCFL225-FL255

DELEGATED TO REYKJAVIK

FL55 AND ABOVE

FL245-

DB-FL660

DB-FL660

FL255

FL245-FL255

DB-FL255

DB-FL255

DB-FL255

DB-FL045

DB-FL070

DB-FL255

DB-FL255DB-FL255

HUMBER

TYNE

ANTRIM

GALLOWAY

HEBRIDES

MORAY

TALLA

TAYWESTCOAST

GENERAL SECTOR (LOW) -BOUNDARIES

SCMATSGENLO 07.05.03CHANGE: Tay Sector Boundary amended Effective Date 12.02.04

Figure 4-12: Scottish General Sectorisation (Low)




DB-FL660

FL255-FL660

FL255FL285

FL285FL660

DEL TO MACC S29FL255-FL285

FL255-FL660

FLEXIAREA

FL255-FL660

FLEXIAREA

FL255-FL660

DEL TO MACC S29FL255-FL285

FL255-FL660

UB3-UP6BUFFER

DB-FL660

FL255-FL660

DEL TO MONFL255-FL285

HEBRIDES

MORAY

MONTROSE

DEANCROSSSOUTHWEST

CENTRAL

NORTH SEA HIGH AREACOPENHAGEN ATSFL195 AND ABOVE

DELEGATED FROM SHANNON ACCFL255 - FL460

NORTH

SOUTH HUMBER

TYNE

DELEGATED TO AMSTERDAMFL175-FL245

DELEGATED TO REYKJAVIK

FL55 AND ABOVE

SCMATSGENHI 28.04.03CHANGE: Sector Boundary amended to Southwest Sector (western side of UB3/UP6 buffer zone)

GENERAL SECTOR (HIGH) -BOUNDARIES

Effective Date 15.05.03

Figure 4-13: Scottish General Sectorisation (High)




4.8. ATC Voice Communications System – Operational Requirements

En-Route Air Traffic Control (ATC) in the United Kingdom is based upon the division of airspace into sectors, each of which is managed by a team of Air Traffic Controllers. In order that two-way communications may be maintained between the control team and the aircraft under control, each sector is provided with a unique air-ground RT frequency. This frequency is essential for the safe operation of ATC and therefore requires a high level of integrity. Frequencies are allocated to an ATC channel.

Some frequencies are used for other purposes, e.g. Flight Information, Distress and Diversion and Oceanic Clearance Delivery. Some of the applications may require less demanding levels of integrity but for the purpose of the radio system design, all frequencies are considered to require the same (i.e. the highest) level of integrity.

The volume of airspace within which reliable two-way communication can be obtained on any given radio frequency is called the frequency coverage. The recommended signal strength considered necessary to provide reliable communications is specified in ICAO Annex 10 Volume 3. In general, coverage is required throughout the sector in accordance with specified minimum and maximum heights.

The use of any frequency in the aeronautical band is subject to international agreement in order to avoid mutual interference between co-channel and adjacent channel assignments. The airspace volume within which agreement has been obtained to use a frequency is known as the Designated Operational Coverage (DOC). The frequency may not be used outside this airspace volume.

4.9. Frequency Planning

Every VHF (and UHF) RTF channel employs a discrete frequency assignment. In order that the radio spectrum can be used efficiently the same frequency can be assigned to geographically separate services. However, sufficient separation must be provided to ensure that the probability of co-channel and adjacent channel interference is acceptably low. As a result of the long line of sight propagation distances that can be achieved between aircraft in flight, the actual re-use distance can be many hundreds of miles. The frequency planning process is therefore, by necessity, an international co-ordination activity.

The specific mechanism whereby frequencies are assigned depends upon the frequency band employed and the operational use to which the frequency is put. Within the European Region, frequency planning for aeronautical VHF communications is carried out within ICAO's European Air Navigation Planning Group (EANPG), Frequency Management Group (FMG), with the secretariat function being provided by EUROCONTROL. Within the UK, the civil Radio Regulator (the Radio communications Agency, an Executive Agency of the Department of Trade and Industry) has delegated the responsibility for frequency management in the aviation bands to the Civil Aviation Authority (CAA). The task is carried out in the Surveillance and Spectrum Management Section of the Directorate of Airspace Policy (DAP SSM), which acts as the UK State representative in the aviation planning process.

Following successful application for a frequency assignment for an Air Traffic Service Provider (e.g. NATS, Ministry of Defence), approvals for new frequency assignments are issued by CAA (DAP) in a formal letter. This letter details:




a) The Air Traffic Control Centre to which the frequency is assigned and its co-ordinates;

b) The Licensee;

c) The Service Type;

d) The Assigned Frequency;

e) The DOC;

f) Minimum (Recommended) Field Strength within DOC;

g) Maximum (Recommended) Field Strength outside of the DOC;

h) Class of Emission;

i) Effective Date.

Subject to the channel being operated in accordance with the licence, air-ground communications should be maintained within the DOC without being affected by co-channel or adjacent channel interference.

4.10. NERL Radio System Description

Air Ground RTF communications are provided in two frequency bands allocated by the ITU. Communication with civil aircraft, and those military aircraft that are suitably equipped, is carried out in the VHF band allocated to the Aeronautical Mobile (Route) Service between 117.975 MHz and 137 MHz. Communications with military aircraft are carried out in parts of the Band allocated to the Aeronautical Mobile Service between 230 MHz and 400 MHz. The band between 230 MHz and 400 MHz straddles the VHF and UHF Bands but is generally referred to as the UHF Band in order to differentiate it from the VHF Band between 117.975 and 137 MHz.

The channel frequency spacing employed in the VHF band is predominately 25 kHz but 8.33 kHz channel spacing is being introduced progressively across Europe for some communications channels. No 8.33 kHz channels are currently in use in UK airspace. All NERL provided VHF services employ Double Side-Band Amplitude Modulation.

The radio systems employed by NERL have the following general characteristics:

Multiple radio transmission and reception facilities at numerous radio sites.

Operation by multiple controllers at each ATCC.

Control and monitoring of the system by engineering staff at each ATCC and Service Management Centre (SMC).

4.11. RF Coverage from NATS Airports

Unlike those for En-Route RT channels, airports DOCs are fairly standard. The following generic set of coverage rules apply:

A Ground/Ground UHF coverage is defined as "within the Airport boundary";

G/G VHF 5 or 10 miles from the airport boundary;

Tower VHF 20 or 25 miles from the airport boundary;

Approach VHF 40 or 60 miles from the airport boundary;




ATIS etc. 60 miles from the airport boundary.

4.12. RF Coverage from NERL Radio Stations

The coverage obtained from each of NERL's radio stations is predicted using a commercially available propagation modelling tool. This tool allows the use of a range of propagation models, and the inclusion of topographic information takes account of the effects of terrain.

Plots of transmitter coverage for each radio station are developed based on minimum wanted field strength at the edge of coverage of 75 microvolts per metre at VHF. Operational experience indicates that the theoretical coverage predictions, produced using the tool, provide a realistic estimate of the actual coverage provided.

The coverage on each RTF channel is planned to match the corresponding defined operational requirement (i.e. the Designated Operational Coverage). The radio stations hosting each RTF channel are selected primarily on their ability to provide the required coverage. However, to provide redundancy and hence minimise channel failure rate, it is a design aim that coverage is provided from at least two radio stations.

Each ATCC provides air traffic services over a large volume of airspace, often remote from the Centre itself. It is therefore necessary to locate radio stations within the required volume of interest and to enable the controllers to operate the radios at these stations remotely from the ATCC.

In some cases the size of a sector is such that coverage cannot be obtained from a single radio station. In this case the frequency may be transmitted from more than one radio station, geographically distributed to provide ‘Area Coverage’.

Figure 4-14: Predicted Area coverage - Moray Sector at 10,000 ft (amsl)




In certain critical sectors (especially Terminal Control), full overlapping coverage is required from two or more radio stations to increase channel leg availability. This type of coverage is known as ‘Duplicate Coverage’.

Figure 4-15: Predicted Duplicate coverage - TC NW DEPS Sector at 3,000 ft (amsl)

Channels with a 25 kHz assignment requiring two or more radio stations to meet the operational coverage requirement employ the multi-carrier system. Multi-carrier operations involve all ground to air communications for a particular frequency being transmitted simultaneously from each radio station. For air to ground transmissions all radio station receivers in the multi-carrier group are operational and the best received signal will be passed to the controller.

For both area and duplicate coverage, NERL employs a multi-carrier solution, using the ICAO CLIMAX (offset carrier) standard configurations. In order to provide the required coverage and provide redundancy to achieve the required reliability, each channel is operated from 2, 3 or 4 radio stations. A channel leg carries a single frequency between one radio station and an ATCC.

4.13. Multi-carrier Operations

As outlined in section 4.11, multi-carrier operation in the ground to air direction is achieved by using the offset carrier or CLIMAX system. This technique allows up to 5 separate radio stations (4 is the current maximum used within NERL) to simultaneously transmit the same audio signal using a single frequency assignment. Each channel leg employs a discrete carrier frequency that is offset from the assigned frequency. The frequency offsets are chosen so that they are contained within the aircraft receiver acceptance bandwidth and first order heterodyne frequencies generated are above the audio pass-band of the receiver. To meet these criteria the following offsets are normally used in the En-route Radio Telephony System but other combinations may also be used:




No. of Climax legs

Leg 1

TX frequency

Leg 2

TX frequency

Leg 3

TX frequency

Leg 4

TX frequency

Leg 5

TX frequency

2 fc + 5 kHz fc – 5 kHz

3 fc + 7.5 kHz fc fc – 7.5 kHz

4 fc + 7.5 kHz fc – 7.5 kHz fc +2.5 kHz fc -2.5 kHz

5 N/A to UK N/A to UK N/A to UK N/A to UK N/A to UK

Table 4-1: Offset-carrier Operation

fc is the assigned channel frequency.

Three and four station offset carrier systems will also generate second order heterodyne frequencies. These are generated from the first order heterodynes and appear at the lower end of the aircraft receiver’s audio band. To limit the effect of these heterodynes, transmitters are used having carrier frequency instability of less than ± 40 Hz at VHF.

Figure 4-16: Multi-Carrier Transmit Overview




Figure 4-17: Multi-Carrier Receive Overview

4.14. Radio Station Configuration

The majority of NERL’s ATS radio stations are ‘split sites’ in that they consist of separate transmitter and receiver sites located a few kilometres apart. The separation provides isolation between transmitter and receiver systems and allows a greater number of frequencies to be operated without causing mutual interference. Where separate sites are impractical, or where only a small number of frequencies are required, a ‘combined site’ (i.e. combined transmitter and receiver site) is used. The two architectures are similar. The main differences lie within the geographical separation between the transmitters and the receivers for split sites.

4.15. Radio Function

4.15.1. Transmit Function

Two identical sets of equipment ("A" and "B") are provided at the radio station, each set providing one transmitter per frequency. Speech and PTT are passed to the transmitter via the RTF Control & Monitoring system. The transmitter produces an amplitude modulated double sideband signal (A3E, in accordance with ICAO Annex 10 Volume 3).

For VHF transmissions, the rated output powers and associated frequency stabilities are as follows:

VHF (25 kHz standard – 2 legs) 75W 5.0 ppm

VHF (25 kHz high-stability oscillator – 3+ legs) 75W 0.3 ppm




The outputs of up to six transmitters (each a different frequency) are fed to an aerial combiner system and then onto a common aerial. Aerials are normally vertically polarised dipoles.

4.15.2. Receive Function

Two identical sets of equipment ("A" and "B") are provided at the radio station, each set providing one receiver per frequency. Speech and Aircraft Call are passed to the Air Traffic Control Centre via the RTF Control & Monitoring system.

Mute Lift on the receivers is set for a Signal + Noise / Noise ratio of at least +15db. However, a Mute Carrier Override function ensures that any signal above +90dbm will be treated as a valid Aircraft Call.

4.16. Aerial Systems

The aerial systems used for transmission and reception in both the VHF and UHF bands are broadly similar. To minimise tower-loading requirements, multiple transmitters or receivers are connected to a single aerial using a combiner. In transmit aerial systems this combiner is a passive device incorporating cavity resonators.

Connections between the aerial combiner and the aerials are made through an aerial distribution cabinet that provides the flexibility to manually connect services to any aerial and select a spare aerial in the event of a suspected aerial failure.

The VHF aerials used have a free space polar diagram equivalent to a vertical dipole and have a fixed coaxial cable tail attached to the main feeder by a coaxial connector. The aerials are attached to the aerial support structure so that the effects of the support structure on the polar diagram are minimised and there is minimum coupling between aerials. On aerial towers and columns, this is achieved by mounting the aerials on the end of boom arms and ensuring that aerials mounted on the same leg of the tower are vertically in line.

4.17. RF Design

The design of VHF air-ground communications system is based on the requirements of CAP 670 Part C COM 02 – VHF Aeronautical Radio Stations and the Standards and Recommended Practices contained in ICAO Annex 10 Volume 3, Part 2 Chapter 2. The basic requirement is that communications of a defined quality of service shall be provided within the radio service area appropriate to the services being provided. Within NERL, a generic design has therefore been developed that is capable of meeting the requirements of all en-route VHF channels and is based on achieving a minimum line of site range of 175 nm from a radio station.

4.18. Ground to Air Communications – Regulatory Issues

In order to provide the required coverage and speech quality, ICAO Annex 10 recommends that:

On a high percentage of occasions, the effective radiated power (of the ground installation) should be such as to provide field strength of at least 75 microvolts per




metre within the defined operational coverage of the facility, on the basis of free space propagation.

This recommendation is open to some interpretation because the meaning of the term ‘On a high percentage of occasions’ is imprecise. It has therefore been NERL’s practice to plan for minimum field strength of 75 microvolts per metre at the edge of the coverage based on free space propagation. Extensive experience of providing VHF air-ground communications services over the past 60 years has shown this field strength to provide acceptable performance.

The maximum design line of sight range has been set at 175 nautical miles because it represents the line of sight range achievable to an aircraft at 25,000 ft (ignoring the refractive effects of the earth's atmosphere). To achieve this range and minimum field strength of 75 microvolts per metre, the minimum required transmitted EIRP (Effective Isotropic Radiated Power) is 35W.

4.19. Representative UK Airport

London Heathrow has been selected as the representative airport for consideration within the B-VHF Reference Environment description. As one of the world’s busiest airports, Heathrow provides a realistic representation of the challenges facing a future VHF overlay technology within an airport environment.

The expected VHF RF profile at a typical airport consists of:

a) Air Traffic Control and information service frequencies;

b) Airline Operational Communications (AOC) frequencies;

c) Airline data link (ACARS/VDL Mode 2);

d) Airport emergency frequency (e.g. Fire for Aircraft/Fire Service Communications).

The large airline presence at Heathrow airport means that the list of VHF frequencies is extensive. A summary of the frequency allocations to service type is detailed in Table 4-2.

VHF Service Number of VHF Assignments

ATC 6

Departure ATIS 1

Arrivals ATIS 3

AOC 25

Fire 1

ACARS/VDL2 Data link 5

Table 4-2: Service allocation of Heathrow VHF assignments

4.19.1. ATIS Frequencies

There are 4 ATIS frequencies associated with Heathrow airport, 3 Arrival and 1 Departure (Table 4-3). ATIS are continuous broadcasts, providing meteorological information and other airport-specific information required by departing and arriving aircraft.




All 3 Arrivals ATIS broadcasts contain common information, but in order to provide wide area coverage, they are broadcast on separate frequencies from separate transmitter sites. It is normal for aircraft to tune to one of the Arrivals ATIS frequencies as soon as possible en route to its destination airport. However, it should be noted that the DOC for an ATIS assignment is 60 nm from the airport boundary (or from the appropriate transmitter site).

The Departure ATIS contains separate information and is intended for use by aircraft within the vicinity of the airport only.

Airport

North Stacks 3 x Arrival ATIS

South Stacks

1 x Departure ATIS Airport

Table 4-3: Summary of Heathrow ATIS service allocation

4.19.2. ATC Frequencies

The 6 Air Traffic Control frequencies in use at Heathrow Tower are split between 4 control functions:

a) Arrivals (1 frequency allocation) - Used by ATC to control aircraft after hand-off from Terminal Control until the aircraft has vacated the active runway;

b) Departures (1 frequency allocation) - Used by ATC in the final stages of departure from entry to the runway holding area until take-off clearance is issued;

NOTE: At the present time, the Arrivals and Departures frequencies are each permanently allocated to their specific function. This means that, when the runways swap between Arrivals and Departure functions (a regular occurrence at Heathrow, carried out each day), the active frequency in use on each particular runway changes over. In order to simplify cross-coupling procedures for ground movement vehicles, it is intended, at some future point, to change this concept of operation so that the same frequency is permanently allocated to a particular runway.

c) Ground Movement Planning (GMP - 1 frequency allocation) - Used for the Delivery function. This frequency enables initial communication to be established between ATC and aircrew of departing aircraft while at the departure gate (terminal building);

d) Ground Movement Control (GMC – 2 frequency allocations) - There are 2 (GMC) frequencies at Heathrow – known as GMC1 and GMC2. The airport surface is divided into 2 distinct areas, each area being allocated one of the GMC frequencies – Figure 4-18. The GMC frequencies are used for all ATC communications with the aircrew following the initial instruction to pushback until the aircraft reaches the entry point to the runway holding areas;

e) Standby (1 frequency allocation) - Available for use by any of the ATC functions.




Figure 4-18: GMC Split at Heathrow (reproduced by kind permission of BAA plc)




ATC will, at all times, retain positive control over allocation of RF frequencies to aircraft within the airport environment. In general, this means that GMP will normally be used at the gate only. GMC will normally be used between the gate and runway holding areas. DEPARTURES and ARRIVALS will normally only be used within the runway holding areas, on the runway and at runway exit points. Within this controlled framework, there are no particular operational restrictions at any point regarding ability of the aircraft to transmit on ACARS/VDLM2 or AOC frequencies.

There are no specific separation minima in force for aircraft on the airport surface. However, aircraft are maintained under ATC control at all times. When necessary, ATC will issue instructions to aircrew to ‘hold’ and ‘give way’ to other aircraft. A general rule applies that typically ensures a limit of 1 aircraft per ‘traffic block’ on the airport surface.

4.19.3. Usage Scenario for Airport Frequencies – Departing Aircraft

4.19.3.1. Departure ATIS

Between about 1 hour and 20 minutes prior to departure, the aircrew tune in to Departure ATIS. This broadcast contains meteorological information and other airport-specific information required for departing aircraft.

4.19.3.2. Ground Movement Planning (Delivery)

When ready, the aircrew contact ATC to initiate communications and to progress flight planning details. The information communicated from the aircrew on this frequency includes:

a) Aircraft Type;

b) Gate Number;

c) Current ATIS information (each ATIS broadcast is allocated a unique identifier code);

d) QNH confirmation.

The information communicated from ATC on this frequency includes:

a) Standard Instrument Departure Route (SID);

b) Mode A allocation;

c) Confirmation of Calculated Take-off time (CTOT).

When the aircraft is ready, ATC issues the instruction to start engines. When ATC is ready, ATC issues the instruction to transfer to the appropriate GMC frequency for pushback approval. At Heathrow, the GMC frequency allocated depends upon which part of the airport the aircraft is located.

4.19.3.3. Ground Movement Control

ATC issues pushback approval and controls the aircraft to the entry point to the runway holding areas. There, aircrew are instructed to ‘hold’ and monitor the Departures frequency.

4.19.3.4. Departures

The aircraft is directed to the runway and cleared for take-off on the Departures frequency. After the aircraft has completed its initial turn on the SID, and when it is at




such an altitude as to be clear of ‘Go-Around’ routes for any arriving aircraft carrying out a ‘Missed Approach’ manoeuvre, ATC control of the aircraft is passed to Terminal Control.

A frequency usage schematic for a typical departure scenario is shown in Figure 4-19.

Figure 4-19: ATC Frequency Usage in a Departure Scenario

4.19.4. Usage Scenario for Airport Frequencies – Arriving Aircraft

4.19.4.1. Arrival ATIS

As soon as possible en-route, aircrew will tune to one of the destination airport’s ATIS Arrivals frequencies. For Heathrow, this may typically be at any point over North Western Europe.

4.19.4.2. Arrivals

Aircraft are transferred to the Arrivals frequency by Terminal Control when the correct landing aircraft spacing has been achieved. This spacing is determined by the types of aircraft involved with particular regard to vortex wake effects generated by different aircraft types. After landing, the aircrew are instructed to vacate the runway and to monitor the appropriate GMC frequency.

4.19.4.3. Ground Movement Control

When the aircraft has vacated the active runway, the remainder of its journey to the arrivals gate is controlled on the appropriate GMC frequency. Upon arrival at the gate and when the guidance system indicates that the aircraft is correctly parked, the aircrew will cease monitoring the GMC frequency. There are no further communications between ATC and the aircrew after this point.

A frequency usage schematic for a typical arrival scenario is shown in Figure 4-20.

Figure 4-20: ATC Frequency Usage in an Arrival Scenario




4.20. Future Changes of the Reference UK Airspace

The UK Government’s Air Transport White Paper (ATWP), published in December 2003, sets out a strategic framework for the development of airport capacity in the UK over the next 30 years, against the wider context of the air transport sector. To release current pent up demand, the ATWP gave the green light for a rapid increase in runway capacity, and hence TMA traffic, from 2010 onwards with the total amount of runway capacity increasing rapidly between 2012 and 2020.

The ATWP sets out the following expectation for airport development within the UK (Table 4-4):

Heathrow mixed-mode 2010 (subject to environmental targets)

Stansted second runway 2012

Heathrow third runway 2015 – 2020 (subject to environmental targets)

Birmingham 2016

Gatwick second runway 2019 (if Heathrow does not meet environmental targets)

Edinburgh second runway 2020

Table 4-4: Airport Development in the UK

The ATWP was a catalyst for a more rapid rate of change in the development of UK airspace and the London TMA than has previously been experienced and the impact of the new runways will create significant challenges. The scale of change is unprecedented in commercial aviation history and requires flexible, and sometimes radical, thinking to achieve the goals.

----------- END OF SECTION -----------




5. Airborne Users’ Topology

This chapter provides a brief description of the ATC & CNS Simulation Tool NAVSIM1 that is currently used for the VHF channel occupancy modelling, interference modelling and will be used for the B-VHF system capacity/performance modelling. It explains the general modelling approach for implementing the airborne users’ topology for B-VHF evaluation purposes. Additionally, it provides detailed statistical data about the distribution of aerodromes, ATC sectors and airborne users within the reference B-VHF airspace that are relevant for the B-VHF high-level system design task.

5.1. Air Traffic/ATC & CNS Simulation Tool (NAVSIM)

The following section contains a short description of the simulation tool (NAVSIM) which is used for B-VHF ATC channel occupancy investigation and B-VHF system performance evaluation.

The ATM/ATC & CNS simulation tool NAVSIM is able to simulate in detail the air traffic situation in a region like entire Europe (around 25.000 flights per day, up to 5.000 aircraft simultaneously). In particular, it is possible to simulate separately different phases of each flight:

Pre-flight time at gate

Taxiing to departure runway

Take-off from departure runway

Standard Instrument Departure (SID) Route

En-Route

Standard Terminal Arrival Route (STAR)

Approach, Final Approach

Landing at runway of destination airport

Taxiing to destination gate area

Post-flight time at gate

Dependent on the flight phase it is possible to retrieve from the simulation output specific data that are relevant for communications and thus also for the B-VHF project. For each flight phase it is possible to generate, simulate and analyse realistic ATC- and other voice/data traffic between a ground station and selected aircraft.

5.2. Airborne User Topology

The following airborne user pictures (topologies) will be used by the NAVSIM simulator for B-VHF ATC channel occupancy investigations:

1 The ATC & CNS Simulation Tool "NAVSIM" has been developed by "MCO Mobile Communications Research & Development Forschungsgesellschaft mbH, Salzburg" in co-operation with University of Salzburg.




European air traffic situation as captured on reference day2: July 7th, 2000

Autonomously derived geographic position/altitude data (trajectory) of each B-VHF measurement flight (GPS WGS84 data, as captured onboard measurement aircraft) for accurate B-VHF measurement flight tracking using the NAVSIM.

Above inputs are required for VHF channel occupancy determination and interference simulations, which are carried out in the B-VHF WP 2.

Detailed B-VHF system performance simulations (performed within the B-VHF WP3) require additional data about future development of European air traffic for the years 2015, 2020 and 2025, respectively. Required parameters about the future increase of the European air traffic are captured in the Chapter 10 (Future Air Traffic Development) of this document. Such future air traffic situations will be simulated by NAVSIM, taking additional flights into account (expressed as a percentage increase above reference traffic situation).

With regard to the reference air traffic files of July 7th, 2000 the following is noted:

All flights (even military flights) for which an IFR flight plan was filed appear in the NAVSIM traffic data base.

VFR flights, for which no flight plan has been filed, do NOT appear in the traffic data base and are therefore NOT simulated.

Only flights with departure and destination aerodromes located in European countries are simulated as “baseline” air traffic of July 7th, 2000.

B-VHF ATC channel occupancy investigations and B-VHF system performance evaluations have been carried out by using traffic data for the peak traffic hours of the reference day.

5.3. UK Airspace Implementation within NAVSIM

NERL has provided detailed information on the following types of ATC Sectors:

London ACC and Scottish ACC Sectors (polygons and VHF frequencies)

London and Manchester Terminal Control Areas (polygons)

These data [NERL_GS], which have been implemented in NAVSIM (Figure 5-1, Figure 5-2), are referred to as "NATS data base". Due to the fact that UK Terminal Control Zones (CTRs) were not included in the NATS data base, supplementary data from the existing NAVSIM data base3 and EUROCONTROL COM2 data base [EUROC_VHF] have been used to take also this type of UK airspace into account.

Currently, NAVSIM tool comprises more than 6.400 European ATC sectors and almost 17.000 VHF Frequency allocations derived from these data bases. Each sector is characterised by its geographical 3D boundaries (2D polygons + vertical boundaries).

2 CFMU data provided by EuroControl in the context of past aeronautical communication performance evaluations carried out by UniSBG for other projects. 3 NAVSIM internal data base comprises Swissair Flight Information System (SFS), Digital Aeronautical Flight Information and JEPPESEN NavData.




Figure 5-1: NAVSIM Implementation of UK Airspace

Figure 5-2: NAVSIM Implementation of UK ATC Sectors




Furthermore, an algorithm was specifically developed for the B-VHF project, allowing to associate a given aircraft (defined by its current 3D position within the European airspace) with the ATC sector that is currently responsible for the aircraft control (and the VHF frequency that is used in that ATC sector).

Further detailed B-VHF System performance evaluations using NAVSIM will use this feature to associate each simulated flight with the proper ATC frequency, dependent on the flight position within the simulated airspace.

5.4. ATC Statistics

UK airspace serves as an important reference area for the B-VHF project, as it was described in detail and the first B-VHF measurement flight (July 8/9, 2004) was carried out completely in this area.

The range of 200 nm around the Brussels International Airport (EBBR) is known as European Core Area. The B-VHF system requirements [B-VHF D5] have been defined according to [MACONDO] requirements that in turn were defined for different Homogenous Zones in both Core Area and non-Core area.

NOTE: Around half of the European flights fly within, enter, depart, or over fly European Core Area.

The second B-VHF measurement flight (Aug.31/Sep.1, 2004) was carried out partly in the UK airspace and partly in the European Core Area.

In this section, ATC statistical data for the Core Area centred at Brussels (EBBR) are represented (Figure 5-3), as obtained from the NAVSIM tool for the reference day of July 7th, 2000.

In addition to Brussels (EBBR), also the ATC statistics for circular areas (200 nm) around London Heathrow (EGLL) and Frankfurt (EDDF) are included, as shown in Figure 5-4 and Figure 5-5, respectively.

The following tiers around these three reference points have been taken into account in the simulation/calculation: 200 nm, 150 nm, 100 nm, 75 nm, 50 nm, 25 nm and 12 nm. These tiers are shown in Figure 5-3, Figure 5-4 and Figure 5-5, respectively.

All 26.261 European flights captured for the reference day were simulated/calculated, but only the relevant sections of these flights lying within the specified range have been used for statistical evaluation.

Statistical data provided in this chapter include the number of different objects that may be found within a given tier, including:

Uncontrolled airfields (without an asphalt RWY)

Small aerodromes (one RWY)

Large airports (more than one RWY, except for five very large Core Area airports)

Very large airports (EBBR, EHAM, LFPG, EGLL, EDDF)

NOTE: Five largest European airports within the Core Area (Brussels, Amsterdam, Paris, London, and Frankfurt) have been separately indicated.

Additional data include the number of ATC sectors within a given range (tier), including:

CTR Zones (around an airport)




TMA Sectors (around large airports)

CTA / ACC Low Sectors (below FL245, unless indicated otherwise)

CTA / ACC High (Upper) Sectors (above FL245, unless indicated otherwise)

NOTE: A given sector has been counted as being within a tier if at least a part of it lies within physical tier boundaries.

For each tier the following ATC statistics were retrieved separately for different types of airspace (ATC sectors):

Total number of flights over the period of 24 hours

Maximum number of simultaneously active flights and time at which this occurred

Mean number of simultaneously active flights for each airspace class calculated for each hour (0 to 23) of the reference day (maximum mean value of simultaneously active flights has been tabulated as well)

(Mean of) Maximum number of simultaneously active flights (PIAC) for each airspace class calculated for each hour (0 to 23) of the reference day

Number of aircraft entries per hour for each airspace class, separately calculated for each hour (0 to 23) of the reference day

Mean aircraft dwell time in sector (in minutes) for each airspace class

Total number of active flights within tier and maximum number of active flights for each ATC sector class over the period of 24 hours

Representative detailed data for 200 nm tier around Brussels (EBBR) are shown in Figure 5-6, Figure 5-7, and Figure 5-8, respectively.

Detailed data for other EBBR tiers and other reference areas (EGLL, EDDF) have been made internally available to the B-VHF consortium in the same format.

Table 5-1, Table 5-2 and Table 5-3 summarize statistical data obtained from NAVSIM tool for the European Core Area (200 nm around Brussels), as well for two similar areas centred at London Heathrow (EGLL) and Frankfurt (EDDF), respectively.




Figure 5-3: European Core Area around Brussels (EBBR)

Figure 5-4: Reference area around London Heathrow (EGLL)




Figure 5-5: Reference area around Frankfurt (EDDF)




Figure 5-6: ATC Statistics for range 200 nm around Brussels (EBBR)

Figure 5-7: Detailed ATC Statistics for 200 nm range around Brussels (EBBR)




Figure 5-8: Detailed ATC Statistics for 200 nm range around Brussels (EBBR)

NOTE: In the London Heathrow (EGLL) and Frankfurt (EDDF) area the number of flights is higher than in the Brussels (EBBR) area for ranges smaller than 100 nm (i.e. 75 nm, 50 nm, 25 nm and 12 nm).




ATC Statistics for European Core Area Around Brussels (EBBR)

Distance "d" (nm) from Brussels 12 25 50 75 100 150 200

Number of items within distance "d"

Uncontrolled airfields (no asphalt RWY) 0 3 11 18 24 46 70

Small Aerodromes (1 RWY) 0 0 6 12 15 30 51

Large Airports (> 1 RWY, except very large airports class below)

0 0 1 3 6 9 17

Very large Airports (EHAM, LFPG, EDDF, EGLL, EBBR)

1 1 1 1 2 4 5

CTR Zones 2 5 15 27 35 56 81

TMA/APP 4 11 32 50 67 108 135

CTA/ACC Low 3 6 20 32 53 97 160

CTA/ACC High 1 1 6 9 16 33 55

Total number of flights over 24 hrs 1801 2145 2603 3336 5711 8405 12762

Maximum number of simultaneous flights found over 24 hrs within "d"

29 46 60 100 158 288 475

at UTC time (h:m) 12:54 16:15 11:15 17:05 08:07 12:22 16:28

Max. Average Instantaneous A/C Count found over 24 hrs in any

CTR Zone 1,4 1,3 1,2 1,4 2,5 2,1 1,9

TMA/APP 4,6 3,6 2,7 2,3 2,6 3,1 4,4

CTA/ACC Low 1,4 3,5 2,8 2,5 2,6 2,6 2,8

CTA/ACC High 10,6 12,2 5,9 5,0 5,7 5,3 5,9

Max. Peak Instantaneous A/C Count (PIAC) found over 24 hrs in any

CTR Zone 3,0 2,0 3,0 3,0 7,0 8,0 8,0

TMA/APP 4,0 7,0 9,0 10,0 15,0 14,0 21,0

CTA/ACC Low 4,0 6,0 7,0 8,0 11,0 13,0 15,0

CTA/ACC High 18,0 21,0 17,0 19,0 20,0 21,0 24,0

Max. Average number of A/C entries per hour found over 24 hrs in any

CTR Zone 33,0 19,0 9,7 8,0 12,4 13,5 15,5

TMA/APP 33,0 23,0 15,0 10,8 12,6 16,0 21,5

CTA/ACC Low 9,3 15,3 14,0 15,8 15,6 16,3 15,2

CTA/ACC High 46,0 57,0 24,7 35,4 34,9 31,1 29,0

Average A/C dwell time in sector (m) found over 24 hrs in any

CTR Zone 1,1 1,2 1,9 2,4 2,4 1,9 1,7

TMA/APP 3,5 3,5 3,1 3,3 3,4 3,5 3,8




CTA/ACC Low 5,0 7,3 4,8 4,4 4,6 4,4 4,6

CTA/ACC High 12,5 12,0 8,6 7,5 6,9 7,6 8,1

Max. number of A/C found over 24 hrs in all

CTR Zone 3,0 3,0 6,0 8,0 17,0 25,0 36,0

TMA/APP 12,0 16,0 21,0 27,0 48,0 79,0 134,0

CTA/ACC Low 5,0 17,0 27,0 40,0 62,0 112,0 173,0

CTA/ACC High 18,0 21,0 26,0 45,0 74,0 129,0 207,0

Table 5-1: ATC Airspace Statistics for Brussels Area (EBBR)

ATC Statistics for Area Around London (EGLL)

Distance “d” (nm) from London 12 25 50 75 100 150 200

Number of items within distance “d”




0 2 2 4 6 10 16


1 1 1 1 1 1 4

CTR Zones 1 4 8 10 15 38 64

TMA/APP 1 8 13 17 22 42 77

CTA/ACC Low 0 6 44 78 105 140 172

CTA/ACC High 4 5 21 29 39 55 70


Maximum number of simultaneous flights found over 24 hrs within “d”

27 46 93 128 167 283 405

at UTC time (h:m) 09:47 14:03 12:23 12:23 12:22 12:24 12:40


CTR Zone 2,1 1,8 1,6 1,6 1,6 1,7 1,9

TMA/APP 10,9 5,3 6,5 5,6 5,6 4,6 4,7

CTA/ACC Low 0,0 1,6 2,1 2,1 2,2 2,3 2,5

CTA/ACC High 2,0 2,8 2,3 2,0 2,6 4,1 4,7


CTR Zone 7,0 4,0 4,0 7,0 7,0 6,0 7,0

TMA/APP 22,0 8,0 20,0 20,0 22,0 23,0 22,0

CTA/ACC Low 0,0 3,0 9,0 10,0 16,0 16,0 16,0

CTA/ACC High 5,0 8,0 8,0 8,0 12,0 28,0 38,0





CTR Zone 80,0 34,0 31,0 30,4 23,2 14,8 16,1

TMA/APP 108,0 38,6 48,0 49,0 45,9 30,9 27,9

CTA/ACC Low 0,0 17,0 14,8 15,8 14,6 14,9 15,6

CTA/ACC High 11,8 17,8 11,0 11,8 15,0 17,3 19,0


CTR Zone 1,4 1,7 1,7 1,8 1,9 2,4 2,1

TMA/APP 6,2 4,1 3,5 3,3 3,3 3,5 3,9

CTA/ACC Low 0,0 2,7 3,1 3,0 3,2 3,5 3,7

CTA/ACC High 6,3 6,8 4,5 4,9 5,4 7,8 8,0


CTR Zone 7,0 10,0 12,0 15,0 15,0 23,0 36,0

TMA/APP 22,0 31,0 47,0 48,0 48,0 60,0 103,0

CTA/ACC Low 0,0 6,0 36,0 57,0 77,0 107,0 143,0

CTA/ACC High 11,0 13,0 22,0 33,0 52,0 131,0 177,0

Table 5-2: ATC Airspace Statistics for London Area (EGLL)

ATC Statistics for Area Around Frankfurt (EDDF)

Distance "d" (nm) from Frankfurt 12 25 50 75 100 150 200

Number of items within distance "d"




0 0 0 0 1 4 9


1 1 1 1 1 1 3

CTR Zones 1 1 3 5 15 40 72

TMA/APP 2 4 9 19 42 86 148

CTA/ACC Low 3 9 13 23 58 113 159

CTA/ACC High 1 3 7 12 16 31 39


Maximum number of simultaneous flights found over 24 hrs within "d"

37 51 88 120 176 302 446

at UTC time (h:m) 14:24 13:31 15:27 15:27 15:27 13:11 13:18





CTR Zone 1,8 1,8 1,8 1,6 1,3 1,2 1,5

TMA/APP 8,9 6,4 6,1 4,3 2,5 2,0 2,1

CTA/ACC Low 3,8 3,7 3,8 3,5 3,1 2,9 2,9

CTA/ACC High 13,5 8,1 8,9 7,7 6,6 6,1 7,1


CTR Zone 4,0 4,0 4,0 4,0 4,0 4,0 5,0

TMA/APP 14,0 14,0 14,0 14,0 14,0 14,0 13,0

CTA/ACC Low 8,0 12,0 11,0 11,0 11,0 13,0 13,0

CTA/ACC High 22,0 17,0 19,0 16,0 17,0 21,0 21,0


CTR Zone 57,0 57,0 52,0 31,5 11,3 9,6 10,7

TMA/APP 90,0 40,0 30,7 17,8 11,5 10,5 12,5

CTA/ACC Low 24,5 17,7 20,7 19,1 15,3 15,9 15,8

CTA/ACC High 57,0 37,0 42,6 33,0 37,1 32,6 36,5


CTR Zone 1,4 1,4 1,4 1,3 1,4 1,4 1,7

TMA/APP 5,6 4,6 4,4 3,9 3,3 2,9 2,7

CTA/ACC Low 8,5 8,6 7,3 6,6 5,7 5,3 5,1

CTA/ACC High 13,6 12,6 10,4 9,1 8,1 8,3 8,4


CTR Zone 4,0 4,0 4,0 6,0 8,0 13,0 24,0

TMA/APP 14,0 15,0 15,0 18,0 27,0 41,0 73,0

CTA/ACC Low 13,0 25,0 38,0 53,0 79,0 139,0 200,0

CTA/ACC High 22,0 25,0 53,0 63,0 94,0 159,0 211,0

Table 5-3: ATC Airspace Statistics for Frankfurt Area (EDDF)

----------- END OF SECTION -----------




6. Operational Aspects of VHF Voice Communications

The information provided in this chapter supplements/extends the information about operational aspects of ATC voice communications in the UK (Chapters 4.8 – 4.18 of this document).

6.1. Introduction

Today, ATC uses an analogue VHF voice communications system based on the DSB-AM (A3E) emission type with half-duplex user’s access to the communications channel. This system provides moderate speech quality with reasonable transmitting power and acceptable price of the communications equipment.

VHF ATC voice frequency assignments lie within the aeronautical COM band (118-137 MHz). Within the same band, some other types of communications services may exist.

Different ATC functions (e.g. airport control, terminal control, area control) require adequate physical radio coverage. Voice communications must be provided with adequate performance within a whole coverage area. In some cases, required radio coverage may be obtained from a single physical radio site, but sometimes it is necessary to install several radio sites at adequate physical locations.

ATC controller and all pilots within his sector or area of responsibility represent so called “user group” and share the same communications channel. Today, voice communications channel is identical with the VHF frequency assignment (for each sector a dedicated 25 kHz or 8.33 kHz frequency is assigned).

Each member of the user group – controller or pilot - permanently monitors transmissions of all other group members (“party-line” feature). This increases the situation awareness within the user group. Monitoring of the voice traffic is also required for the access to the communications channel.

VHF voice communications are provided in a broadcast manner. Selective addressing is technically possible, but is not operationally used in VHF band, as it is not compatible with the party-line concept.

NOTE: User’s identification is operationally required and executed in the practice, but this is performed outside technical voice communications system through applying operational procedures (controllers/pilots identify themselves by verbally exchanging aircraft- and ATC facility identifiers at the beginning of the voice session).

6.2. General Characteristics of Voice Communications

[MACONDO] provides important information about future use of voice communications within the ATM concept.

Despite the introduction of the data link, voice communication still plays a key role in 2015 ATM context.

a) Voice exchanges are performed in a real-time interactive way.

In the aeronautics environment the sequence of events is very fast due to the aircraft dynamics. The access to an aircraft for tactical clearance happens within few seconds. The data link may be very efficient for automatic tactical exchanges between ground and




airborne systems, but it does not seem likely that it may provide enough interactivity for tactical communication between humans (message transmission itself can be made pretty fast, but there will always remain bottlenecks at the man machine interface level). Whenever two human beings are in the loop, it seems to be more efficient to use a direct voice contact for tactical exchanges.

b) Voice processing done by the human receiver does not pre-empt cognitive capabilities.

The exchange of tactical information can be therefore performed in parallel to other tasks such as aircraft control and navigation, which are fundamental to ensure flight safety. The controller/pilot can perform other cognitive tasks in parallel. The data link on the other hand, as long as it is based on the use of textual interfaces, does not allow this non pre-emptive process, as the semantic analysis or the received message locks the processing resources of the brain for few seconds.

c) Voice flow conveys more sense than the sole sentence meaning.

Information is also contained in the voice tone and rhythm. In this way, voice exchanges contribute to a more global awareness of the situation. Usage of data link is recommended in parallel to the voice communications to avoid false interpretation of received information.

For those reasons, apart from the fact that this media derives from today monopoly (removing it would mean a real operating concept revolution), Voice Communication will remain the primary means for exchanging tactical information.

Certain trends can be foreseen at the 2015 horizon:

1. For new communication systems, the audio quality of voice is expected to increase due to the generalisation of digital transmission, and consequent use of channel coding techniques

2. The introduction of Data Link will mean that the usage of voice communications may be reduced for some exchanges (mainly strategic functions), while its usage for tactical information exchange is expected to follow air traffic increase (instead of being reduced). This trend will introduce a slightly different channel load share amongst the airspace volume,

3. Digital transmission will enable new added value voice services such as :

Addressed Communication with caller Identification

Automatic hand-over in the mobile network

Priority level indication

Group services

Integrated Voice / Data services

6.3. Classification of Voice Services

The classification of voice communications services available today in European airspace has been found in [EUROCONTROL_1] and is shown in Table 6-2.

Today all voice services are provided to “User Groups” in a broadcast manner. Within the User Group, the voice service is today non-saturable: party-line and broadcast services virtually support any number of aircraft within an ATC sector.




The communications channel is accessed by obeying the “listen-before-PTT” protocol. Access collisions are possible, but if the humans strictly comply with the operational procedures, they occur only occasionally. For continuity reasons, the future system should also adopt legacy “listen-before-PTT access” protocol for voice services.

Broadcast services may be considered as a special case where only one member of a user group (ground system) has permanent access to the channel.

When the channel duty-cycle exceeds some limit (e.g. 60%), the controller’s mental workload increases above acceptable safe limit, so the User Group (sector) is split into two smaller User Groups (sectors) and each such group is assigned its dedicated VHF voice channel.

Today, one dedicated VHF channel is allocated for each party-line or broadcast voice service. One dedicated channel is also used for the pilot-pilot service. There is a strict [B-VHF D5] requirement that the future communications system shall also provide a dedicated functional voice channel for each air traffic controller and a common group of users (e.g. an ATC sector).

At large airports, several OPC voice channels may be allocated for AOC purposes. Each such channel is either dedicated to some particular airline, or shared among several airlines. Like ATS voice communications, OPC voice communications are also provided in a broadcast manner.

In [MACONDO] six types of voice services have been defined that are expected to be operationally required by the year 2015 and are represented in the Figure 6-1 (reprinted from [MACONDO]).

Table 6-1 lists voice service classes indicating the required/expected physical connectivity (air-air/A-A, air-ground/A-G, ground-air/G-A, ground-ground/G-G), as well as the service provision mode (PP = point-to-point, BC = broadcast, MC = multicast) as indicated in [MACONDO].

Party-line and broadcast voice services (CoS v1, CoS v4) are already existing classes (used today). One dedicated channel is also used for the pilot-pilot service (CoS v3).

Selective services (CoS v2, CoS v5, CoS v-AOC) are “future services”, as they are today not operationally used (at least not in the VHF communications range). These classes will require additional HMI and additional procedures to establish on-demand voice circuits. After connection establishment phase the access to the voice circuit will be PTT-based.

AOC voice communications have not been included in [MACONDO], however they can be considered in a broader context as one additional service class, having characteristics similar to the CoS v5.

The way the OPC voice service is provided in the future (CoS v-AOC) may be completely different than the way it is provided today.




Service Class

Description Connectivity Required

Mode Current VHF Technology

CoS v1-1 Controller-Pilot Party Line Service- Voice Tactical Exchanges

A-G, G-A, A-A, G-G

BC VHF/DSB-AM

CoS v1-2 Controller-Pilot Party Line Service- Voice Full-system D/L Backup

A-G, G-A, A-A, G-G

BC VHF/DSB-AM

CoS v2 Controller-Pilot Selective Voice Service - Selective Aircraft Backup

A-G, G-A PP/ MC

N/A

CoS v3 Pilot-Pilot Voice Service A-A BC/MC VHF/DSB-AM

CoS v4 Broadcast Service G-A BC VHF/DSB-AM

CoS v5 Interactive Voice Service A-G, G-A PP/MC N/A

CoS v-AOC Voice AOC Service A-G, G-A PP/MC VHF/DSB-AM

Table 6-1: Voice Service Classes and Connectivity

Figure 6-1: MACONDO Voice Service Types




Type SERVICE SUB Serv. Description Com Type Rec. Coverage (NM, FL) Comment LoadingAerodrome

AFIS Aerodrome flight information service A/G G/A 16/30 HeavyATIS Automatic terminal information service G/A only 60/200 Broadcast HeavyTWR Aerodrome control service A/G G/A 16/30 or 25/40 HeavyAS Aerodrome surface communications G/G 0/0 HeavyPR Precision approach radar A/G G/A Heavy

ApproachAPP Approach control service A/G G/A 25/100 40/150 or 50/250 Heavy

En RouteF Flight information service A/G G/A FIR HeavyACC Area control service A/G G/A Area FL up to 430 or 450 Heavy

Other E Emergency (121.500 MHz) A/G G/A SAR Search and rescue (123.100 MHz) G/G GUARD Guard frequencies around "E" and "SAR" channels -OPC Operational control A/G G/A Circular HeavyVOLMET Meteorological broadcast for aircraft in flight. G/A only BroadcastA/A Air to air A/AA/G Air ground communication channel A/G G/A Circular 16 NM 3000 FT Normal

PARA Parachuting A/A A/G G/A Circular FL150 HeavyBAL Ballooning A/A A/G G/A Area FL195 NormalEQT Equipment test G/G Circular LowRFT Research and flight testing A/A A/G G/A LowFLT Flight testing of radio navigation aids and communications facilitiesA/A A/G G/A LowGLD Gliders A/A A/G G/A Area FL195 HeavyHANG Hang gliders A/A A/G G/A Area FL150 HeavyINST Instruction A/G G/A UML Ultra and micro-light operations A/G G/A Circular 16 NM 3000 FT NormalMAINT Maintenance G/GMIL Military use A/G G/ANLA National light aviation A/G G/A UL Ultra light aircraft A/G G/AGAI Services at uncontrolled airport provided by non-licensed personne A/G G/A Circular 16 NM 3000 FT NormalRGA Regional general aviation A/G G/A RLA - A/G G/A SAFE Safety related services A/A A/G G/A Area FL100 Low

Table 6-2: Today’s Operational Voice Service Types




6.3.1. Pilot-Controller Voice Services

This service corresponds to the current operational use of voice communications within managed airspace. It supports all classes of information (distress, tactical, strategic, information). In managed airspace, the pilots have the mandatory requirement to stay permanently connected to the applicable pilot-controller voice service.

This type of service may be provided in two modes:

a) Pilot-Controller Party Line Voice Service (CoS v1-1, CoS v1-2) has a star topology directly derived from the way the traffic management is operated today; i.e. one ground controller manages a number of aircraft. Within a “user group”, everyone can monitor the voice channel activity and talk (the “Push to talk” media access protocol requires permanent monitoring of the voice channel busy/idle status). This mode allows for tactical exchanges between the controller and the aircrew (CoS v1-1), but also for future non-selective voice exchanges needed as a backup in case of data link failure (CoS v1-2).

b) Pilot-Controller Selective Voice Service (CoS v2) is not supported by the existing voice system. It is intended to be operated in point to point (or point-to-multipoint) manner with selective addressing between ground and air. It may in the future replace the Party-Line service, mainly to provide a backup to the data link outside TMAs.

6.3.2. Voice Broadcast Service

This service type (CoS v4) offers the capability to broadcast pre-recorded voice information to the group of aircraft. This service is mono-directional in the ground to air direction and will have to remain operational for aircraft not equipped by the data link.

6.3.3. Pilot-Pilot Voice Service

This service type (CoS v3) allows tactical, strategic or information exchanges between pilots flying close to each other. It is also used to relay information from ground to aircraft that are out of range. This service uses the “Push to talk” media access protocol (that in turn requires permanent monitoring of the voice traffic). This service can be either operated as a Party Line or Point to Point, but the existing voice system only supports the Party Line (broadcast-) mode of operation, also allowing the air traffic controller to monitor the pilot-pilot dialogue.

This type of voice service does not involve the ground air traffic controller, so it is not linked to an ATC sector.

6.3.4. Interactive Air-Ground Voice Service

This service type (CoS v5) is currently not used (not linked to an operational concept). It offers the capability to perform a point to point call from an operational ground position (not necessarily air traffic controller’s position) to a dedicated aircraft. From an operation point of view it provides the same features as the Pilot-Controller selective service, but its area of application is different.




6.4. Medium Access for Voice Communications

6.4.1. Party-line with PTT-based Channel Access

The information provided in this section is related to non-broadcast voice services (CoS v1-1, CoS v1-2, CoS v3) from the Table 6-1. The broadcast mode (CoS v4) also uses PTT keying, however without multiple access (as the ground broadcast station is the only user on the VHF channel).

Today, a dedicated communications channel (VHF frequency) is assigned to each ATC sector. The channel is used by a “user group” – ATC controllers and pilots currently being within this sector.

All pilots of controlled flights have to permanently monitor the currently assigned ATC frequency. This allows the ATC controller to uplink important information, but also enhances the situational awareness for all pilots within the user group: as they hear each other, they can create a mental picture of the air traffic situation in their neighbourhood.

Monitoring of the channel activity via party-line is also an integral part of the medium access protocol (for ATC voice communications channel access has been “delegated” to humans). At any given time only one user is allowed to transmit (only one transmitter may be active within a given user group). Each user wanting to access the channel must previously check (by monitoring the voice traffic on the channel) that the channel is currently not occupied by any other user ("listen- before-PTT" protocol).

NOTE: The content of voice traffic on the channel is not relevant for the medium access, it is important only to make sure that no other user has already accessed the channel by activating (keying-) his transmitter.

PTT-based access to the communications channel reflects the operational nature of the controller-pilot voice communications: while one party speaks, another one is supposed to listen, in order to avoid unnecessary repetitive transmissions of the same information.

This means that, even if full duplex capability were available within the voice system, the users would continue to follow half-duplex conversation pattern because of operational reasons!

PTT-based channel access is today globally used, while any new system – including B-VHF - could initially be introduced at most at the regional level. This means that, regardless of the selected MAC solution for a new system, in the rest of the world the PTT access to the channel would continue to be used for a long period of time.

It is therefore recommended to consider the half-duplex channel usage with PTT-based access when designing the B-VHF system.

6.4.2. Voice Delay and Signalling Delay

This section describes the process of establishing/releasing the voice communications session within existing analogue VHF system.

In this example shown in the Figure 6-2, it has been assumed that the controller has direct access to the ground radio transmitter. For radios located at remote sites, significant ground delay may appear between the moment of the PTT activation and the moment the PTT signal has reached (remote-) ground transmitter. This ground delay must - together with the VCS-internal delay - be taken into account when evaluating the end-to-end required performance of the voice communications system.




The process of accessing the communications channel starts when the controller activates (presses) his PTT key (“A”). The keying signal (it is a level signal rather than an event signal) must be present at the transmitter input for the whole duration of the voice transmission (the PTT key is released again at the moment “G”). When PTT signal reaches input of the radio transmitter, the transmitter starts to produce DSB-AM RF carrier at its antenna output. RF carrier with a nominal power may be observed at the transmitter antenna (“B”) after some delay tKEY (10-20 ms)

As the pilots and controllers are trained to wait for some time (tH, 20-70 ms) after having activated the PTT key before they start to speak (“D”), this carrier is initially not modulated. The users have also been trained to keep their PTT key depressed for some minimum time after they have completed the voice message (“F”) to make sure that the whole voice message was contained within the active PTT keying time (as otherwise the end of the message may be cut-off). Ignoring the short keying time tKEY, it may be said that the RF carrier is present as long as the PTT key remains depressed.

When the user starts to speak (“D”), the transmitter starts to produce modulated DSB-AM signal with the envelope that has only a minimum delay (tAF_TX, several ms) with respect to the incoming voice signal. The modulated DSB-AM RF signal is produced only when the user actively speaks – during the speech pauses the unmodulated carrier is transmitted.

When the RF carrier (after propagation delay tP of max. 1,3 ms for 200 nm distance) reaches the receiver antenna, after some time tSQ (about 20-50 ms) the receiver’s audio output (“C”) opens (squelch action). From this moment on, the receiver noise (or later on demodulated voice-) is presented at the RX audio output, with only a minimum delay (tAF_RX, several ms) with respect to the envelope of the modulated DSB-AM RF signal.

The listening pilot or controller can easily distinguish between the inactive (silence) and active (increased noise/voice present) state of the communications channel and use this information for the own access to the channel.

After the transmitting user has released his PTT key (“G”), the transmitter’s carrier signal will after some time tKEY drop to the level that cannot be detected by the receiver anymore. The receiver’s squelch circuitry will after some time (approximately tSQ) suppress the audio signal at the receiver output (“I”), indicating to the receiving user that the channel become idle again.

It can be concluded that, in the absence of the ground delay, total end-to-end voice delay is relatively small (about 15 ms), given by the relation:

tV = tAF_TX + tP + tAF_RX

Total signalling delay tSIG between the moment the controller has activated his PTT key and the moment the pilot(s) become aware that the channel is now occupied is typically larger than the voice delay:

tSIG = tKEY + tP + tSQ

Without ground delay contribution, tSIG typically ranges between 30 and 70 ms. When using narrowband in-band signalling for the PTT signal transmission between the controller’s working position and the remote radio site, there is an additional contribution (ranging at some 50 ms) to tSIG.

It is necessary to keep the signalling delay tSIG (including the ground delay contribution) as small as possible, as otherwise communications collisions may occur due to the simultaneous channel access of several users.




NOTE: One user presses his PTT key at the moment ”A”, but other users become aware about the changed channel status at the moment “C” (after tSIG ). In the meantime, any of them may activate his PTT key (as his squelch barrier has not yet been broken, he believes that the channel is idle), causing overlapping reception by all user group members. Normally, air traffic controller resolves such communications collisions, at a cost of increased workload.

Within the existing analogue system, an air traffic controller cannot interrupt any ongoing transmission as long as any other user keeps his PTT key in the active state. An unintentionally activated PTT key ("stuck microphone") by any member of the user group can block the communications channel for all users.

t

t

t

PTT signal at TX input

Voice signal at TX input

t

t

Voice signal at RX output

SQ signal at RX output

RF signal at TX output

tSIG

tAF_RX

tSQ

tH

tKEY

tAF_TX

tSQ

tP

tP

tV

A

B

C

D F

G

H

I

E

tKEY

Figure 6-2: Voice Communications Session




This deficiency could be mitigated if the current half-duplex operation for voice were supplemented by the duplex signalling mechanism, giving the controller the opportunity to disrupt ongoing airborne transmission after he detected a communications collision.

6.5. Voice Communications System Architecture

Voice communications services required for the ATC are today generally provided to the air traffic controllers by the Voice Communications System (VCS). General VCS architecture is shown in Figure 6-3.

The Human Machine Interface (HMI) of the VCS supports configuration and provides access to specific radio functions (e.g. direct radio access, management of radio resources, offset-carrier wide area coverage, frequency coupling or best signal selection).

The VCS provides to the controller audio interface (e.g. headset, handset, loudspeaker/microphone), as well as signalling interface (PTT key).

Ground Networks or Leased Lines

Sector_A

VCS

CWP

GS_S_RXGS_S_TXGS_M_RXGS_M_TX

GS_S_R_IFGS_S_T_IFGS_M_R_IFGS_M_T_IF

Controller

f_A f_A

f_A

f_A f_A

Figure 6-3: VCS Architecture

On the other side, VCS provides dedicated interfaces (e.g. GS_M_T_IF, GS_M_R_IF in Figure 6-3) for the radio equipment (transmitters and receivers).

ATC controllers and the VCS are located at ATC service units, while the radios are located at physical locations that have been selected to provide required radio coverage range.

VCS radio interfaces are connected to the remote radio sites over a ground communications infrastructure – either analogue or digital leased lines or radio networks. In some cases, ATC service units and corresponding radio sites are co-located, but sometimes they are separated by hundreds of kilometres. Interconnecting infrastructure




(dedicated analogue/digital lines, networks) may introduce significant transmission delay both for voice and associated signalling (PTT/SQU).

6.6. Uplink Voice Monitoring

While airborne voice radios operate as true transceivers (either transmitting OR receiving at any particular time), ground ATC voice radios are mainly operated as separated transmitters and receivers. The transmitters can be operated independently of the current receiver status or usage. This gives the air traffic controller the possibility to monitor his own uplink voice transmission (in UK, this is called “off-air side-tone”) by using the same receiver that is otherwise used for receiving pilot’s voice downlinks. By this way, each time he presses his PTT key, the controller gets the confirmation that the whole radio chain – comprising transmitter, receiver and their antenna systems – operates properly.

This feature requires that the whole audio path between the controller (being close to VCS in Figure 6-3) and the remote radio site is passed twice: first the controller’s voice and associated PTT signal are transferred to the remote site and used to key the transmitter and produce modulated radio signal, then the received/demodulated controller’s voice signal (and optional squelch break signal) are transferred in the opposite way.

Ground networks or leased lines between the VCS and the remote radio site may introduce significant voice/signalling delays, the VCS itself and the on-site radios also contribute to the overall delay budget.

If the voice end-to-end delay between the pilot and the controller exceeds some 400 ms, the conversation dynamics may suffer (ITU-T Recommendation G.114).

If the voice round-trip delay from the controller to the transmitter and from the receiver back to the controller exceeds some limit4, the controller will experience unacceptable echo.

Because of these reasons, there is a constant pressure to the suppliers of ATC voice systems to reduce voice delay to the absolute possible minimum.

6.7. Best Signal Selection/Best Transmitter Selection

Airborne emissions can be received by multiple ground receivers within the coverage area. Each receiver receives downlink signal with different signal strength, leading to possibly different noise contribution in the demodulated audio signal.

In order to present to the controller only one signal instead of garbled mixture of signals, best signal selection function (voting) is typically implemented somewhere between the receiver bank and the controller’s working position. The best signal selection function remains always active, during both uplink and downlink transmissions. Voters can be implemented as stand-alone devices inserted between the receiver bank and the VCS, but can also be integrated within the VCS itself. 4 This limit is not fixed, it rather depends (ITU-T Rec. G.131) on the amount of voice delay as well as on the level difference between the voice and echo signals. Round-trip delay typically lies [NERL] in the region of 15-20 ms, values above 20 ms are considered as unacceptable.




One popular method for the best signal selection uses Signal-to-Noise (S/N) evaluation of the incoming signal at the radio interface of the VCS. Another method is based on the received signal strength (RSS-) as measured by the ground receiver.

NOTE: Although the voting is always external to the radio system, indicating the quality of the received signal (in support of the second above method) remains a desirable feature of any new radio system.

When employing selective transmitter keying for uplink, the controller has to decide on which channel leg (from which transmitter site) the voice should be transmitted. An obvious choice for the ongoing voice session is to use the transmitter associated with the receiver that was rated best at the last downlink transmission.

The best transmitter selection may be supported by the VCS, but in all cases the controller must be able to de-activate/overrule automatic VCS TX selection.

NOTE: Controller may need manual TX- selection e.g. when he just closed the communication session with an aircraft and now wants to call new aircraft at the opposite “far” border of the service area.

6.8. Wide Area Coverage

Sometimes wide area coverage from multiple radio sites is required for large ATC sectors on a single VHF frequency. Two common approaches are offset carrier (CLIMAX) systems and selective transmitter keying.

6.8.1. Offset Carrier Operation (CLIMAX)

Offset-carrier system may be used to provide hot standby redundancy even if no true wide-area coverage is required. This method is fully transparent to controllers and pilots.

According to [CLIMAX_SPECT], the method is widely spread (there are 382 CLIMAX allocations in 27 European States). The same reference provides a detailed table describing each of these allocations.

ICAO Annex 10 specifies 4 offset-carrier modes, with 2, 3, 4 and 5 “channel legs”. Each transmitter uses different offset from the nominal channel frequency.

Typical offset values for 2, 3, 4 and 5 channel legs are ±5 kHz, 0/±7,5 kHz, ±2,5/±7,5 kHz and 0/±4/±8 kHz, respectively. Other offsets values may be used as well (except for the 5-legs system), as long as the maximum frequency deviation from the nominal value remains below ±8 kHz and the minimum frequency distance between carrier frequencies of different channel legs is less than 4 kHz.

Offset only works with 25 kHz voice channels – offset operation with 8.33 kHz system is currently being investigated, but is not yet operationally used.

Offset-carrier emissions are always ground- originated. Carrier frequencies for a number of ground transmitters are slightly “offset” from their nominal value. During uplink transmissions, all offset transmitters are simultaneously keyed.

The IF bandwidth of the typical DSB-AM radio receiver is typically much wider (exceeding 16 kHz) than the bandwidth of each single transmitted RF signal (about 7 kHz). The same applies to the ground ATC receivers (they are typically used for controller’s monitoring of own uplink emissions). Airborne (and monitoring ground-) receivers can




therefore simultaneously receive signals of all offset transmitters. This situation is illustrated in the Figure 6-5 for the system with four legs.

Figure 6-4: CLIMAX Allocations in Europe

f_A (-1) f_A (+1)f_A (-2) f_A (+2)

Figure 6-5: Offset-carrier Uplink Signal with Four Legs




Figure 6-6 illustrates offset-carrier operation with three legs. Controller’s voice is simultaneously transmitted from three different radio sites and is received by both airborne and ground monitoring receivers.

An airborne transceiver always transmits on the middle frequency (without offset) and is simultaneously received by an unlimited number of ground receivers. As the received signal strength (and thus the signal quality) may be very different among the involved ground receivers, received signals are fed towards the VCS, its internal Best Signal Selection (BSS) function selects the strongest signal and presents it to the controller.

Ground Networks

or Leased Lines

Sector_A

VCS

BSS

CWP

GS_2_RXGS_2_TX GS_3_RXGS_3_TXGS_1_RXGS_1_TX

GS_2_R_IFGS_2_T_IF GS_3_R_IFGS_3_T_IFGS_1_R_IFGS_1_T_IF

Controller

f_A(0) f_A(0) f_A(0)

f_A(0)

f_A(-) f_A(+)f_A(0)

f_A(0)f_A(0)

Figure 6-6: Offset-carrier (CLIMAX) Operation with Three Legs

6.8.2. Selective Transmitter Keying

A popular alternative method for wide area coverage is selective transmitter keying. Like the offset-carrier operation, this method is fully transparent to the pilots.

With this method, all radios operate on the assigned nominal channel frequency (without offset). During the ground emissions only one ground transmitter is keyed at any time. The selection of an appropriate transmitter may be supported by the VCS, but in some cases still requires manual controller’s intervention, so the procedure cannot be considered to be fully transparent to the controllers. The airborne receiver always receives the emission of a single ground transmitter (overlapping multiple uplink transmissions are not possible with this method).

All ground receivers within a range simultaneously receive airborne emissions, producing voice signals that are – as in the offset-carrier case - subject to the best signal selection (voting).




6.8.3. Combined Method

It is possible to combine offset-carrier with selective transmitter keying. One “main” ground transmitter may be tuned to the positive offset, while “n” supporting transmitters are tuned to the negative offset. During each uplink session, the "main" transmitter is simultaneously keyed with one of the supporting transmitters. In this case, the VCS is responsible for selecting exactly one transmitter pair during each session. In the downlink direction, all available receivers can be simultaneously used, in combination with the best signal selection function.

The controller always has the possibility to revert to the single transmitter operation by manually selecting only the main or one of standby transmitters for his next uplink emission.

6.9. Channel Coupling

Channel coupling is a common operational practice during periods of low air traffic where for efficiency reasons single air traffic controller controls several sectors. This feature is supported by the VCS and provides pilot-to-pilot party-line functionality between different VHF frequencies (as different sectors use different frequencies, pilots of aircraft flying within adjacent sectors cannot directly hear each other).

The big advantage of this method is its transparency: the coupled sectors functionally become a single large sector, all users from all coupled channels become members of a large “coupled” user group, coupled communications channels become a single communications channel (party-line is extended over all coupled frequencies).

Selecting frequencies for coupling is a static configuration, but may be re-arranged at any time, dependent on the traffic situation. Generally, all radio channels available within the VCS system are also available for coupling, but the sub-set of channels available for coupling at a given time at some specific working position also depends on the coupling configurations of other working positions.

NOTE: The coupling must be generally considered to be a VCS function rather than a radio function, due to the fact that voice communications for coupled sectors may be supported from a single radio site, but also from different physical locations.

The controller transmits on uplink in parallel on all coupled frequencies and is simultaneously heard by all pilots within the whole coupled airspace. Each pilot monitors as usual his assigned sector frequency and may transmit on downlink only if he found that this frequency was idle.

In order to avoid overlapping downlink transmissions it is necessary to provide to the pilots in all coupled sectors the information about the active/inactive status of the “common” party-line channel. VCS supports this task by re-transmitting (uplinking) each downlink on any of the coupled frequencies on all other frequencies from the pool (Figure 6-7).

VCS converts a squelch break of a ground receiver on the frequency fA into PTT signal for all transmitters on frequencies different than fA (in this case fB and fC). Re-transmission on frequency fA is not used/not allowed as it would block ground station’s reception on that frequency.

The controller always hears the sum of all received signals on all coupled channels. This is necessary, as the controller sometimes has to resolve communications conflicts that




occur if two or more users from different sectors try to access the “shared coupled channel” at nearly the same time.

If the channel coupling is used together with the selective TX- addressing, the best RX A/G signal (as determined by the voting function) is re-transmitted on the coupled channels.

G round N etw orks

o r L eased L ines

S ector_CS ector_BS ector_A

V C S

Σ

CW P

G S _B _R XG S _B _TX G S _C _R XG S _C _TXG S _A_R XG S _A_TX

G S _B _R _IFG S _B _T_IF G S _C _R _IFG S _C _T_IFG S _A_R _IFG S _A_T_IF

C ontro ller

f_A f_B f_Cf_A f_Cf_B

f_B

f_A f_C

Figure 6-7: Coupling With Re-transmission

6.9.1. Wide Area Coverage with Channel Coupling

VCS normally supports the "extended" coupling function, where one or several of coupled frequencies belong to the wide area offset coverage chain.

With respect to the coupling, VCS handles all channels from the same offset chain as a single frequency: if the offset chain has been selected for coupling, the coupling will affect all legs at all ground-stations.

6.10. Frequency Handover

ICAO policy requires that at any moment only one ATC authority should be responsible for the safety of a given flight. In order to have clear delimitation of the responsibility, each user group uses its dedicated VHF frequency assignment.

As an aircraft moves between different types of airspace (Airport, TMA, En-route), the aircrew must manually switch the ATC voice frequency of their radio equipment. The operating VHF frequency or the new sector is announced via voice at an appropriate time




prior to the moment the aircraft reaches the new sector boundary by the air traffic controller responsible for the current sector. The pilot must explicitly confirm the handover instruction by voice readback.

NOTE: Manual frequency hand-over is a clear deficiency of the existing analogue voice system. Any future system should provide support for the automated hand-over in the form of an automated internal function (however with an obligatory notification to the pilot).

6.11. System Redundancy

ATC voice communications have stringent availability requirements derived from the safety analysis. Different ATS service providers prefer different solutions to achieve required availability figures. These solutions include e.g. doubled VCS equipment, doubled radio equipment at each radio site, multiple implementations of ground radio stations for each communications channel, as well as usage of a radio network between the ATC facility and remote radio sites.

It is possible to install several ground radio stations for each frequency channel. Such separate radio stations can host main and standby radio equipment and are attached to the Voice Communications System (VCS) via separate radio interfaces.

Normally the controller will select the radio equipment from the main radio site as long as it operates correctly. However, the controller can at any time manually select the radio equipment from the standby radio site. Optionally, switching from main to standby equipment can be initiated automatically, after an error of the main system has been detected by an automated performance monitoring system.

----------- END OF SECTION -----------




7. Operational Aspects of VHF DL Communications

This section provides ATS data link service classification, sample profiles for AOC data link, description of ACARS, ATN and broadcast data link system architectures, brief survey of VDL2 and VDL4 data link technologies, as well as relevant information about data link coverage in Europe.

Within the VHF range, different kinds of data links are in use or are planned to be used in the future. In Europe, these comprise ACARS-based AOC and FANS-1/A data links, ATN-based VDL2 and VDL4 point-to-point data links, as well as the VDL4 broadcast data link.

NOTE: VDL3 data link has been considered in USA, but has not gained acceptance in Europe.

ACARS AOC and FANS-1/A data links are legacy systems using in-band ACARS modem and voice-grade radios that should be phased-out and replaced by the ATN/VDL2 data link. A part of the European fleet may still use ACARS technology at the moment of the introduction of the B-VHF technology.

Due to the LINK2000+ programme, European ATN/VDL2 data link equipage will increase and it is expected that within the next decade a significant part of European IFR flights will be ATN/VDL2 capable. Broadcast non-ATN/VDL4 data link may also be in operation in parts of European airspace in the B-VHF time frame.

The description also comprises ACARS/VDL2/VDL4 coverage diagrams in Europe.

7.1. Classification of Data Links and Data Link Services

In the context of safety-related point-to-point aeronautical data link, ICAO distinguishes between Air Traffic Services (ATS) and Aeronautical Operational Control (AOC) data link. These two categories are in the focus of the B-VHF project.

Additional ICAO (non-safety) data link categories are Aeronautical Administrative Communications (AAC) and Aeronautical Passenger Communications (APC). As these are currently neither allowed, nor supported within the aeronautical VHF COM band, they are only of secondary interest for the B-VHF project and will not be further discussed.

NOTE: Assuming the necessary regulatory issues have been resolved, any excess capacity of the B-VHF communications system may be eventually offered to the APC services.

Additionally, there is a class of surveillance data links, using broadcast technologies and providing ADS-B as a basic service. The only broadcast technology in the VHF range is the VDL4 data link.

7.1.1. ATS Data Link

Technically, an ATS data link runs between the avionics data link end-system and the ground ATS data link end-system(s). As the flight progresses, the aircraft ATS data link connection is transferred from a given ground system to another one. These systems may be delivered by different vendors and belong to different ATS authorities. As a safety-related communications mean, the complete ATS data link chain is subject to international standardisation (ICAO) and interoperability assessment (RTCA/EUROCAE).




ICAO definition of ATS generally comprises Air Traffic Control (ATC), Flight Information Services (FIS) and alerting services. An ATS data link may therefore be used for different purposes, e.g. for exchanging messages between humans, but also for exchanging data between automated systems. Such data are exchanged by using so called data link services. An operational data link service [ODIAC] describes a set of actions and associated data link messages that have a clearly defined operational goal and which begin and end on an operational event. The later means that operational data link services are invoked within the context of a “broader” operational function at the moment where data synchronisation is required between different actors.

In [MACONDO] 13 generic types of ATS data link services have been defined. Some of them include humans (pilots and controllers), while others deal with fully automated exchanges between automated systems.

Table 7-1 lists data service classes indicating the required physical connectivity (air-air/A-A, air-ground/A-G, ground-air/G-A), as well as the anticipated service provision mode (PP = point-to-point, BC = broadcast, MC = multicast).

Service Class

Description Connectivity Required

Mode Current VHF Technology

CoS D1-1 Pilot-Controller Emergency Dialog A-G, G-A PP N/A

CoS D1-2 Pilot-Controller Tactical Dialog A-G, G-A PP VDL2, ACARS

CoS D1-3 Pilot-Controller Strategic Dialog A-G, G-A PP VDL2, ACARS

CoS D1-4 Pilot-Controller Information Dialog A-G, G-A PP VDL2, ACARS

CoS D2 Pilot-Pilot Dialog (RESERVED) A-A PP/ MC N/A

CoS D3-1 Medium Flight Information Exchanges A-G, G-A PP VDL2, ACARS

CoS D3-2 Large Flight Information Exchanges A-G, G-A PP N/A

CoS D4-1 ATM Tactical Exchanges A-G, G-A PP N/A

CoS D4-2 ATM Strategic Exchanges A-G, G-A PP N/A

CoS D5-1 Downlink of Tactical Aircraft Data A-G BC/MC N/A

CoS D5-2 Downlink of Strategic Aircraft Data A-G BC/MC N/A

CoS D6-1 Ground to Air Surveillance Broadcast G-A BC VDL4

CoS D6-2 Air Surveillance Broadcast A-A (A-G) BC VDL4

CoS D-AOC AOC Data Link A-G, G-A PP VDL2, ACARS

Table 7-1: Data Link Service Classes and Connectivity

CoS D-AOC data link has not been considered in [MACONDO], but it has been internally added to the functional scope of B-VHF voice communications.

It can be seen in Table 7-1, that existing- or nearly-implemented VHF data link systems provide support only for a sub-set (CoS D1-2, CoS D1-3, CoS D1-4, CoS D3-1, CoS D6-1, CoS D6-2, AOC) of data link service classes. Remaining service classes are currently either supported over non-VHF data links (e.g. Mode S GICB protocol, 1090 ES), or no support exists at all.




7.1.1.1. Pilot-Controller Exchanges

CoS D1-1 Emergency Exchanges service consists of point-to-point in-flight exchanges of emergency messages, therefore imposing very stringent quality of communication criteria, with low transmission delay, highest priority and best availability.

CoS D1-2 Tactical Dialog service consists of point-to-point in-flight exchanges of messages on a tactical plan (meaning that a change in flight parameters is required in real time): the messages should be transmitted within some seconds from end to end.

CoS D1-3 Strategic Dialog service consists of point-to-point in-flight and preparation exchanges of messages on a strategic plan (meaning that a change in flight parameters should be required in a future point of time). The messages should be received some thirty seconds after publication.

CoS D1-4 Information Dialog service consists of point-to-point in-flight exchanges of information messages, not directly dealing with aircraft operation. That is why the QoS requirements imposed by this service are not very demanding.

7.1.1.2. Pilot-Pilot Dialog

CoS D2 service consists of adapted clearances that are exchanged between two pilots for the purpose of co-ordination. It could be either a point-to-point, or a multicast service, depending on the operational requirements underlying.

7.1.1.3. Flight Information Exchanges

CoS D3-1 Medium Flight Information Exchanges service consists of flight information messages provided to the aircrew during flight.

CoS D3-2 Long Flight Information Important Exchanges service consists of (long-) flight information messages provided to the aircrew during flight.

7.1.1.4. ATM Exchanges

CoS D4-1 ATM Tactical Exchanges service consists in exchanging point-to-point information on aircraft route (or flight route modification) between the aircraft and the ground. The transfer should be performed on a tactical plan, impacting the QoS requirements.

CoS D4-2 ATM Strategic Exchanges service consists in point-to-point establishing and agreeing 4D trajectory contracts between the aircrew and the controller. The nature of exchanged data is strategic, with corresponding QoS demands.

7.1.1.5. Downlink of Aircraft Data

CoS D5-1 Downlink of Tactical Aircraft Data service relies on the automatic sending of aircraft parameters extracted from the airborne system to the ground (broadcast or multicast).

CoS D5-2 Downlink of Strategic Aircraft Data service relies on the sending of pilot preference parameters to the ground (broadcast or multicast).




7.1.1.6. Ground to Air Surveillance Broadcast

CoS D6-1 service provides current aircraft surveillance information from ground system to airborne mobile systems. This is a broadcast service between the ground surveillance system and the aircraft in the vicinity.

7.1.1.7. Air Surveillance Broadcast

CoS D6-2 is surveillance service transmitting parameters for utilisation by any air and/or ground users requiring it. This is an air-initiated broadcast service.

7.1.2. AOC Data Link

Airlines intensively use data link to exchange messages between the Airline Operational Centre (AOC) and aircraft belonging to their fleet. Messages can be sent in both (uplink, downlink) directions.

The AOC data link information is exchanged between the host computer at Airline Operational Centre and the equipped aircraft of that particular Airline over the whole flight duration, following the basic exchange profile. AOC data link applications are tailored to the needs of the particular airline, so there is no need for global ICAO standardisation or interoperability between avionics and host systems of other Airlines. Indeed, Airlines require more privacy and security features (as AOC data link may convey business-sensitive items, data privacy is very important).

An example data link profile for Lufthansa fleet [LH_DL] is given in Figure 7-1.

Figure 7-1: Representative DLH AOC Data Link Profile




Another example obtained from the SAS web page (http://www.sasflightops.com/) is shown in Figure 7-2. This reference also gives some idea about the performance of AOC data link as currently used by the Airlines.

There is no maximum end-to-end delivery time guarantee for ACARS messages. However, approximately 99,5% of all messages are delivered in <60 s. Average real-life delivery time performance for the uplink messages is 10-20 s, for the downlink messages 5-10 s.

Average real-life message delivery success rate is better than 99% for downlink messages and 95% for uplink messages.

Figure 7-2: Representative SAS AOC Data link Profile

http://www.sasflightops.com/




7.2. Network Technologies

7.2.1. ACARS

Aircraft Communications Addressing and Reporting System (ACARS) is in use for more than 10 years. ACARS is an industrial standard that has been developed for AOC purposes. It is not capable to provide QoS required for safety-related ATS services. Airline Operational Control (AOC) uses ACARS data link to exchange airline-specific messages with its ACARS-equipped aircraft. Due to the ACARS coverage, an aircraft can be reached almost anywhere in the world.

In order to be able to use ACARS data link, airlines must subscribe to an ACARS Service Provider (SP). SITA and ARINC are currently the only SPs providing global coverage. SPs provide all the infrastructure and ground access points to the DL. Both SPs have centralised Data Link Processors (DLPs) that perform specific tasks:

Conversions between various ground access protocols and the air-ground ACARS protocol

Switching/routing of air-ground packets over ACARS subnetworks (SATCOM/VHF/HF)

Handling user mobility within each subnetwork and roaming between subnetworks

DLP keeps track about which subnetwork currently provides connection to the particular aircraft and over which Ground Station (GS)

Figure 7-3 shows end-to-end ACARS architecture. On the airborne side, the AOC data link applications server is typically integrated in the Flight Management System (FMS). It uses communications services provided by the ACARS Management Unit (MU) and offers the corresponding data link HMI to the pilot.

The ground AOC data link user must also implement an AOC applications server and data link communications end-system capable to communicate with centralised ACARS DLP (“Centralised A/G Switch and Communications Gateway”). Ground connections over SPs ground networks use different kinds of communications protocols. Single ACARS A/G communications protocol is used between the DLP and the MU in the avionics over different A/G subnetworks. These include SATCOM, HF DL, VDL2, AoA – “ACARS over AVLC” (using VDL2 radios in non-ATN mode) or PoA – “Plain old ACARS” (using voice-grade radios with in-band modem).




ServiceProvider's

GlobalWANs

Service Provider'sGlobal WANs

Radio towerSATCOM

GES

GND HMI

Satellite

AOC DLApplic.Server

RGS

AOCDL EndSystem

ACARS MU(End System)

FMS

HF AntennaHF GS

Central A/G Switch andComms GW

HighFrequency

(HF)

Airline OperationalCentre (AOC)

X.25

IP

Very HighFrequency

(VHF)SATCOMData 2

HMI(AOC)

Ground-groundAccess Protocols

AOC DLApplications

AOC DLApplications

ACARSMobility

Management

ACARSAir-ground

CommunicationsProtocol

Figure 7-3: End-to-end ACARS Data Link Architecture

7.2.2. ATN

The Aeronautical Telecommunication Network (ATN) has been designed to provide safety-related data communications services to Air Traffic Service provider organisations (ATS data link) and Aircraft Operating agencies (AOC data link). The ATN has been specified to meet specific safety and security demands of aeronautical communications.

The ATN supports communications services between multiple ground systems as well as between ground and airborne systems. The ATN is capable to integrate existing fixed and mobile data networks (they become “ATN subnetworks”).

ATN Technical Specifications can be found in [ICAO 9705], ATN Guidance Material in [ICAO 9739].

With respect to the A/G data link, ATN provides

End-to-end data integrity

Priority and pre-emption (resource management)

Policy based routing (e.g. selection of A/G data links)

Support for user mobility (within each A/G subnetwork)

Support for roaming between different subnetworks

Data compression (over A/G data link)

Standardised set of communications applications

ATN protocol suite is based on the ISO-OSI seven layer model (Figure 7-4).




The layers 1-4 constitute the “ATN Internet”, while the layers 5-7 belong to the Upper Layer Architecture (ULA). At the layer 7, ATN provides communications services that can be used by external systems. At the layer 3, ATN provides specific internet services. The layers 1 to 3a represent so-called subnetworks that are standardised separately from ATN. In the mobile communications context, these represent mobile aeronautical subnetworks like VDL2, AMSS-Data 3, HFDL.

Figure 7-4: ATN Protocol Stack

The ATN data link communications services are released in packages.

The CNS/ATM Package 1 includes the following A/G applications:

Context Management (CM)

Automatic Dependent Surveillance (ADS)

Controller Pilot Data Link Communications (CPDLC)

Flight Information Services (FIS)

For each of above applications there is a dedicated Applications Service Element (ASE) in the Layer 7 of the OSI stack. These ASEs are used by the operational communications services (e.g. DLL, ACM, D-ATIS, ADS-C) that are external to ATN.

CNS/ATM Package 2 has been developed to cover aspects missing in the CNS/ATM package 1 like security, system management and directory services. It also adds the Generic ATN Communications Service (GACS) ASE to the Layer 7. GACS provides support for AOC ATN data link and new ATS data link applications not covered by existing Package 1 ASEs.

7.2.2.1. ATN Infrastructure

The ATN infrastructure comprises ATN End Systems (ES) and Intermediate Systems (IS/ BIS routers), being connected over different subnetworks. End Systems host ATN communications applications and implement all seven layers of the ISO-OSI model. The End Systems communicate with each other over the ATN Internet. Intermediate Systems are concerned with routing of information between ESs and must implement only three lowest ISO-OSI layers and a suite of ATN routing protocols.




So called Boundary Intermediate Systems (BIS routers) must be implemented in each of ATN domains. The part of the communications chain spanned between BIS routers is called an ATN subnetwork. An aircraft is also an ATN domain and must implement a BIS router, either in the form of a separate Communications Management Unit (CMU), or as a combined BIS/ES unit called Air Traffic Service Unit (ATSU).

The connection mode transport protocol (TP4) must be implemented within each ES supporting ATS services. TP4 ensures end-to-end reliable delivery of data packets. It performs a checksum operation on each data packet and re-transmits packet on packet loss or corruption. It also provides end-to-end flow control. TP4 protocol is not mandatory for AOC communications. ATN also supports connectionless transport protocol to be used for non-ATS purposes.

ATN compatible A/G subnetworks (VDL2, VDL3, VDL4, SATCOM, HFDL, Mode S DL) already support users’ mobility (mobility per se is not an ATN Internet function), however, the ATN must support roaming between mobile subnetworks (an aircraft may move serially from one mobile subnetwork to another and may be simultaneously attached to more than one mobile subnetwork). In support of user’s mobility, ATN BIS routers must implement the Inter-Domain Routing Protocol (IDRP).

Due to the fast development of IP-based ground networks and QoS they can provide, the acceptance of ATN for ground communications is today very limited.

However, ATN remains the only realistic network option for the A/G addressed data link communications in the mid-term, at least for the following reasons:

No mature end-to-end IP -based concept is available for aeronautical A/G communications

Introduction of IP-based A/G communications would require long standardisation and validation process, while an “appropriate” ATN solution already exists

Huge investments have been made to develop ATN-compatible A/G subnetworks that must be preserved

The current trend is therefore to integrate IP-based ground networks into ATN framework (convergence is achieved via dedicated IP SNDCF).

The ATN end-to-end architecture is shown in Figure 7-5.

ATN-capable Airlines and ATSPs (Figure 7-5) must install ATN End Systems and DL applications servers with associated HMIs. In order to access the ATN Internet, the ESs must be attached to the G/G ATN routers.

ATN A/G communications require the involvement of the A/G BIS routers. These must implement special features like mobile SNDCF. A special kind of A/G BIS router – Communications Management Unit (CMU) must also be implemented in the avionics.

An A/G BIS router communicates with the VDL2 GSs over WANs. In Figure 7-5 an X.25-based example is shown, however, the most of today’s ground-ground networks are IP-based networks.

The ground A/G BIS router and the rest of the ground subnetwork infrastructure, including the VDL2 Ground Station, may be either provided by the ATSP itself, or delegated to the Communications Service Provider (in Europe, the ATN/VDL2 ground data link infrastructure will in the mid-term be deployed by SITA and ARINC).




DL ServiceProvider's Global

WANs

ATS ServiceProvider's

WANs

Radio towerSATCOMGES

GND HMI

Satellite

ATC DLApplic.Server

VDL GS

ATCATN EndSystem

ATN CMU(A/G Router and

End System)

FMS

Air Traffic ControlCentre (ATC)

X.25

IP

VHF DigitalLink (VDL)

SATCOMData 3

HMI(AOC)

ATS and AOC ATNApplications

GND HMI AOC DLApplic.Server

AOCATN EndSystem

Airline OperationalCentre (AOC)

G/G ATN Router

G/G ATN Router

A/G ATN RouterX.25

HMI(ATS)

ATN End Systemand Routing SW

ATN EndSystem SW

ATN End-to-end

TransportProtocol

(TP4)

ATN EndSystem SW

ATS ATNApplications

AOC ATNApplications

ATNGround-ground

Subnetworks

ATNAir-ground

Subnetworks

Figure 7-5: ATN Architecture

VDL2 GS shown in Figure 7-5 is built in such a way that it can support non-ATN (AoA) AOC VDL2 data link at the same time as ATN-based ATS data link. Within the CMU architecture there is a provision for a gateway between the ATN- and ACARS stacks (implemented above the VDL2 SNDCF). This means that the physical VDL2 communications channel can be “shared” between ATS ATN- and non-ATN AOC applications.

In the avionics, it is necessary to install the appropriate airborne radio and connect it to the CMU that acts as the airborne A/G BIS router and implements higher layers of the subnetwork protocol stack. CMU also implements functions and protocol layers associated with other alternative A/G subnetworks (SATCOM, HFDL).

The CMU is connected to the FMS that acts as an airborne ATN ES and DLP. In the Airbus system, the CMU functionality is extended (Air Traffic Services Unit, ATSU), so it acts as A/G BIS, ES and a data link applications processor.

The pilot’s access to the ATS data link is provided in the form of a dedicated HMI, while the access to the AOC data link is usually provided by using the HMI that is already used for ACARS data link.

7.2.3. Broadcast Data Link

The only A/G broadcast data link in the VHF range is VDL4. When VDL4 is used as an ATN subnetwork, the Figure 7-5 architecture applies. When VDL4 is used in non-ATN broadcast mode, dedicated non-ATN air- and ground infrastructure is required. In




particular, VDL4 subnetwork protocol stack (using VDL4 specific services) is different than the version used in an ATN-compatible mode.

The ground architecture used for VDL4 applications must be able to receive and distribute time critical information to a large number of users. The architecture must also support uplink of information, sometimes time critical, over large areas.

Figure 7-6 shows the ground infrastructure required in support of VDL4 broadcast operation. It consists of dedicated broadcast applications servers (ADS-B, TIS-B, FIS-B) connected over a ground network (“ADS-B network in Figure 7-6) and the ground VDL4 GSs.

Due to the broadcast nature of transmitted data, ground networks must provide adequate transport support. The emphasis is on the timeliness of the data distribution. Existing radar networks are capable to support distribution of ADS-B and TIS-B data (special ASTERIX categories already exist for these types).

TIS-B Server

ADS-B Server FIS-B

Server

ADS-B GS

TIS-B GS

FIS-B GS

PSR/ SSR Radar

ADS-B Network

Radar Network

Non-equipped A/C

Equipped A/C Equipped

A/C

Figure 7-6: VDL4 Ground Infrastructure

7.3. VHF DL Technologies

7.3.1. Channel Access with ACARS, VDL2 and VDL4

A common feature of ACARS, VDL2 and VDL4 data links is that they do not require protected service volumes. All airborne and ground stations can operate on the same VHF frequency, without regard of the ATC sector boundaries or aircraft spatial distribution. In other words, ACARS, VDL2 and VDL4 frequency coverage and operational usage from a given GS is not limited to the specific ATC sector – all aircraft within the coverage range of a GS can communicate with that GS without regard of the ATC sector boundaries.

The consequence is that significantly higher number of aircraft may appear on the common data link channel than on any ATC voice sector channel. Opposite to the ATC voice communications, the number of involved GSs per VDL channel is unlimited.




This is possible while the CSMA MAC protocol (ACARS/VDL2) and STDMA MAC protocol (VDL4) support this kind of operation. With these protocols, only one aircraft or GS is allowed to transmit on the channel at any time. When a given user transmits, all airborne and ground receivers within the coverage range are blocked for the duration of the transmission.

NOTE: The TDMA MAC protocol used by the USA VDL3 solution requires that adjacent GSs use distinct VHF frequencies (requires frequency protected service volumes).

7.3.2. VDL2 Data Link

VDL2 has been specified and validated as an ATN compliant subnetwork. The main Communications Service Providers, ARINC and SITA, are currently deploying airline funded VDL2 ground infrastructure to be shared between AOC and ATC applications (LINK2000+).

VDL2 provides an air/ground bit-oriented point-to-point VHF data link compatible with the ATN. VDL2 is designed to support both AOC and ATS applications and for many airlines is seen as an upgrade to ACARS for their AOC communications needs.

VDL2 uses a Differential 8-Phase Shift Keying (D8PSK) modulation scheme providing 31,5 kbps raw data rate and a CSMA medium access protocol (Carrier Sensing Multiple Access) similar to the VHF ACARS scheme. One VHF channel is shared by all aircraft and ground stations within a range.

VDL Mode 2 subnetwork is not designed to support time critical applications. Due to the access mechanism (CSMA) it exhibits a non-deterministic behaviour, it does not support message priorities and cannot guarantee required performance level in terms of transfer delay.

According to the EUROCONTROL plan [AMCP8-WP44], by the year 2010 VDL2 is planned to operate in Europe on four frequencies at the top of the COM band: 136.975, 136.875, 136,775 and 136,725 MHz, each channel surrounded and protected by guard bands.

It is important to note that these frequencies will be shared between ATS data link traffic and the airlines’ AOC traffic.

VDL2 subnetwork does not provide traffic priorisation in favour of ATS traffic over AOC traffic. Due to the possible impact of AOC traffic, the QoS required by the time-critical ATS services may not always be guaranteed, so these services are deemed to be not deployable over VDL2 (safety concerns).

7.3.3. VDL4 Data Link

[DL_ROADMAP]

VDL Mode 4 (VDL4) is a digital data link designed to operate in the VHF frequency band using one or more standard 25 kHz VHF communications channels. It is capable of providing both point-to-point (including ATN-compatible subnetwork) and broadcast services between mobile stations, as well as between mobiles and fixed ground stations.

VDL4 uses the Gaussian-filtered Frequency Shift Keying (GFSK) modulation scheme that has a modulation rate of 19,2 kbps.

The system uses the Self-organising Time Division Multiple Access (STDMA) concept. The communication channel is divided into 'time-slots'. Slots are grouped into super-frames, each 1 minute long, with 4500 slots in every super-frame. Thus there are 75 slots per




second, and each slot is 13.33 ms in duration. Each time-slot may be used by a radio station to transmit a message. Each station is responsible for prior selection and reservation of the slots it wishes to use.

In order to transmit at the correct time and to ensure global co-ordination between all participating stations, each station requires an accurate time source, normally provided by a GNSS receiver. In VDL4, the time-slots are all synchronised to UTC time.

The self-organising concept allows VDL4 to operate efficiently in a broadcast mode without a need for a centralised co-ordinating ground station. Adding optional ground VDL4 stations and a ground network provides the opportunity to include ATS and other ground users to the broadcast pool.

The services supported in a broadcast mode are the ADS-B function and air-to-air data link communications. The position information required to support VDL4 ADS-B reports is supplied by the aircraft navigation system and avionics. A position report typically occupies one time-slot, while other transmissions, such as ground station transmissions, may occupy more.

When VDL4 is used as an ATN subnetwork, ground stations are mandatory. The rest of the required ground infrastructure is as shown in Figure 7-5. As for VDL2, a Communications Management Unit (CMU) is required in the avionics.

Frequencies for VDL4 in Europe have been proposed by EUROCONTROL at the top of the COM band. The plan has been approved by the ICAO Frequency Management Group in Europe. VDL4 may alternatively operate on 25 kHz frequency channels in the NAV frequency band.

7.4. Data Link Coverage in Europe

ACARS operation on the frequency 136.900 MHz has in the meantime been suspended [SITA AEEC] as SITA has moved its ACARS Terminal frequency (20 Airports) from 136.900 to 136.750 MHz. The move was completed in October 03.

[ARINC AEEC] On June 30, 2004, all ARINC ACARS RGS stations will suspend operation on 136.925 MHz and begin operation on 131.825 MHz (an overnight switch). From June 30 through Sept 30, ARINC will provide a retune service at 18 key European locations for all aircraft appearing on the original frequency. After September 30th, ARINC will be on 131.825 MHz exclusively.

Figure 7-7 and Figure 7-8 (http://www.sasflightops.com) show ACARS coverage for ARINC (at 25.000 feet - FL 250, status 2003) and SITA Base Frequency (at 30.000 feet - FL 300, status 2002), respectively.

Figure 7-9 and Figure 7-10 show ARINC and SITA VDL2 coverage in Europe, based on [ARINC AEEC] and [SITA AEEC], respectively.

Figure 7-11 shows VDL4 coverage at FL 330 (http://www.nup.nu/asp/technical.asp).

http://www.sasflightops.com/

http://www.nup.nu/asp/technical.asp




Figure 7-7: ARINC ACARS Coverage in Europe

Figure 7-8: SITA ACARS Base Frequency Coverage in Europe




Figure 7-9: ARINC VDL2 Coverage in Europe

Figure 7-10: SITA VDL2 Coverage in Europe




Figure 7-11: VDL4 Coverage

7.4.1. Recommendation

As it can be seen from Figure 7-7, Figure 7-8, Figure 7-9 and Figure 7-10, respectively, there is almost seamless ACARS and VDL2 coverage at cruise levels in Europe.

The most ACARS and VDL2 ground stations are located at airports (as the AOC coverage must also be given while an aircraft is on the ground). The chance to find an airport, TMA or en-route airspace in high-density European core area that would not be affected by the ACARS and/or VDL2 operations is very low.

The required ground coverage for VDL4 – if it should be implemented in Europe as an ATN subnetwork – would be similar to the VDL2 coverage. Ground VDL4 station may be receive-only (do not cause interference), but some may also transmit (TIS-B, FIS-B).

An aircraft may transmit on the ACARS or VDL2 frequency anywhere within the “cumulative” coverage range. Considering VDL4, an aircraft may transmit (and cause interference) even if the GS does not exist at all.

The strongest interference may in all cases (ACARS, VDL2, VDL4) be expected to come from another aircraft close to the victim aircraft (even from the same sector).

It is recommended to consider all ACARS, VDL2 and VDL4 frequency allocations with associated guarding bands as “reserved” - non-available to the B-VHF system in all airspace types.

----------- END OF SECTION -----------




8. Voice Communications Profiles

This section summarises the results from the French VOCALISE study [VOCALISE_1] and proposes representative voice communications profiles to be used for B-VHF capacity and performance simulation.

[VOCALISE_1] describes representative ATC voice communications profiles that are suitable for the purposes of the B-VHF project.

VOCALISE constitutes a series of studies carried out by CENA with the purpose to analyse controller-pilot communications on the VHF voice channel. The first phase, covering en-route VHF voice communications, took place in 2000-2001. It was based on 60 hours of French En-Route traffic (ACC), spread over 6 types of sectors (upper air space, border upper air space, upper air space of large extent, Departure and Arrival terminal sectors and FIR), in a situation of heavy traffic. Each type was represented by two sectors and produced 5 traffic samples lasting each one hour per sector.

8.1. VOCALISE Major Findings

This section summarises the main results related to the usage of French en-route frequencies. From the table shown in [VOCALISE_2] an EXCEL sheet has been derived (Table 8-1), summarising the en-route voice statistics according to the requirements of the B-VHF project.

8.1.1. Frequency occupancy rate

The average rate of occupation of the frequency per hour (over 60 hours) is 30%.

Important variations of occupation rate are to be noticed:

5 hours over 40% of occupation (one hour in FIR airspace at 48%),

The occupation varies within one traffic sample: 5 traffic samples have 10 to 15 minutes occupied at over 60% (5 minutes are even occupied at about 80%). Within 5 minute long periods, 7% of them show a value over 50% (16% over 1 minute long period).

It is important to notice that these limited periods of intense occupation are rather likely to condition (at least partially) the sectors splitting. The indicators which are based on the frequency load may, to a certain extent, express certain aspects of the controller's workload (however, the controller's workload may be high even if the frequency traffic is not heavy at the same time).

Figure 8-1 reprinted from [VOCALISE_2] shows the structure of a voice session between the pilot and the controller (relation between contacts, exchanges and verbal acts).




Figure 8-1: Structure of a Voice Session (VOCALISE)

8.1.2. Contact

A contact represents a sequence of all verbal acts between the pilot and the controller (between the first verbal act and the last one) for a given flight. It may contain multiple exchanges. Each exchange may consist of multiple verbal acts.

NOTE: As a theoretical minimum, five verbal acts are required per sector: three for assuming the flight, two for transferring the flight to the next sector.

Contact duration is equivalent to the aircraft dwell time on the sector frequency.

Cumulative contact duration is a sum of the durations of all verbal acts for a given flight. Divided by the contact duration, it gives the “communications ratio”, a figure describing the “rhythm” of communicating with a given flight.

8.1.3. Exchange

An exchange represents a sequence of verbal acts between two speakers, pertaining to one communication subject.

NOTE: One exchange comprises as a minimum two verbal acts (e.g. information request/delivery, clearance delivery/readback).

The duration of an exchange is the elapsed time between the start of the first verbal act and the end of the last verbal act contained in this exchange.

The average duration of an exchange is 11s.

75% of the exchanges are completed in less than 13s ;

90% of the exchanges are completed in less than 19s ;

The longest exchange lasts for 90s (discussion about a TCAS alert).




The exchanges with two verbal acts represent the majority of the exchanges.

these exchanges last for an average of 8s;

95% of these exchanges are completed in less than 12s (with 90% in less than 10s);

8.1.4. Traffic density

Traffic density represents the number of simultaneous contacts (flights) on frequency.

8.1.5. Verbal acts

A verbal act (and the duration of a verbal act) is set out between the taking hold of the microphone until its release.

Up to 15 verbal acts can be found in a single exchange.

45% of the exchanges are made up of 2 verbal acts (instruction/readback or request/reply models).

33% of the exchanges are made up of 3 verbal acts (mainly the first exchanges, assume/assume+instruction/readback).

On average, 2,8 verbal acts can be found within an exchange.

8.1.6. Time of reaction

The reaction time is the time between the verbal acts belonging to the same exchange (between the closure of a first verbal act - pilot/controller releases the PTT key and the start of the subsequent verbal act - controller/pilot presses the PTT key).

The reaction time has been shown neither in Figure 8-1, nor in Table 8-1, but it would apply between pairs of verbal acts (C/P or P/C) within each exchange (C/P, P/C/P, P/C/P/C/P).

Without distinguishing between the pilots and controllers, the average time of reaction is about 1s. The maximum time of reaction recorded is 19s (the pilot doesn't immediately collect the route: maybe he’s checking the waypoints on his map).

Average pilot’s reaction time is 1,1 s (within C/P pair of verbal acts)

Average controller’s reaction time is 1,2 s (within P/C pair of verbal acts).

8.1.7. Consolidated VOCALISE Results

Table 8-1 includes columns (UIRs, FIR, A/Ds), providing calculated representative statistical values for “clusters” of ATC sectors (all UIR sectors, FIR sectors, APP/DEP sectors). These values have been calculated separately for each sector cluster according to the same rules as the TOTAL values in original document.




UIRs FIR FIR DEP D/AsUJ L1L2 JSJU NSNU URUY E1K1 EE BS12 TS TNTB ARR TP

General Frequency occ. rate (%) 24 28 26 33 28 30,5 35 29 32 29,5 27 32 29,5 28 36 32 27 29 28 30 29,7Contacts Nr.of completed/all contacts 129/156 125/227 179/258 164/251 180/236 119/178 111/148 160/233 179/251 160/214 124/184 97/129

Contact duration (min:s) avg. 07:10 16:38 11:54 12:34 16:29 14:32 07:18 11:15 09:16 11:54 08:42 05:22 07:02 06:08 07:30 06:49 10:22 08:43 09:32 08:11 09:51min. 00:30 00:59 00:30 00:12 00:14 00:12 00:12 00:14 00:12 00:12 00:15 00:19 00:15 00:17 01:32 00:17 01:35 02:21 01:35 00:17 00:12max. 13:07 29:55 29:55 20:46 32:29 32:29 20:34 28:21 28:21 32:29 41:42 37:56 41:42 27:35 30:48 30:48 22:09 22:22 22:22 30:48 41:42

Traff ic density avg. 3,6 11,5 7,6 10,4 12,4 11,4 6,7 7,5 7,1 8,7 5,3 6,9 6,1 6,9 5,7 6,3 5,4 4 4,7 5,5 7,2(instant. Nr. of aircraft) min. 0 5 0,0 0 4 0,0 0 1 0,0 0,0 0 0 0,0 0 1 0,0 1 0 0,0 0,0 0,0

max. 8 19 19,0 20 23 23,0 14 14 14,0 23,0 13 17 17,0 17 14 17,0 11 9 11,0 17,0 23,0Ratio of comms.(%) avg. 8 4 6,0 5 4 4,5 10 8 9,0 6,5 11 13 12,0 8 9 8,5 5 10 7,5 8,0 7,9

min. 2 1 1,0 1 1 1,0 2 2 2,0 1,0 1 1 1,0 1 2 1,0 1 2 1,0 1,0 1,0max. 86 32 86,0 87 83 87,0 92 85 92,0 92,0 83 81 83,0 79 39 79,0 19 24 24,0 79,0 92,0

Exchanges Average Nr. per hour 95 105 100 133 121 127 132 103 118 115 100 124 112 123 126 125 126 116 121 123 117Nr. of exc. per contact avg. 3,4 3 3,2 3 2,8 2,9 3,1 3,4 3,3 3,1 3,7 2,8 3,3 2,8 3,3 3,1 4,2 5,3 4,8 3,9 3,4

min. 1 2 1,0 1 1 1,0 1 1 1,0 1,0 1 1 1,0 1 2 1,0 2 2 2,0 1,0 1,0max. 8 6 8,0 8 7 8,0 8 9 9,0 9,0 9 9 9,0 8 9 9,0 9 9 9,0 9,0 9,0

Duration of exchange (s) avg. 9,1 9,7 9,4 8,7 8,4 8,6 9,4 9,9 9,7 9,2 9,7 8,4 9,1 7,9 10,2 9,1 7,4 8,9 8,2 8,6 9,0min. 1 1,5 1,0 0,9 0,9 0,9 1,2 1,4 1,2 0,9 0,7 0,7 0,7 0,5 0,9 0,5 1 0,9 0,9 0,5 0,5max. 38 35 38,0 33 29 33,0 44 79 79,0 79,0 48 27 48,0 26 36 36,0 25 30 30,0 36,0 79,0

Verbal act Average Nr. per hour 265 291 278 363 329 346 364 307 336 320 278 361 320 338 349 344 338 312 325 334 325Nr. of verbal acts/contact avg. 9,4 8,2 8,8 8,2 7,5 7,9 8,5 10,1 9,3 8,7 10,5 8 9,3 7,6 8,9 8,3 11,3 14,1 12,7 10,5 9,4

min. 3 4 3,0 3 3 3,0 3 3 3,0 3,0 3 4 3,0 4 5 4,0 4 5 4,0 4,0 3,0max. 25 18 25,0 22 19 22,0 26 23 26,0 26,0 37 29 37,0 18 23 23,0 28 32 32,0 32,0 37,0

Nr. of verbal acts/exc. avg. 2,8 2,8 2,8 2,7 2,7 2,7 2,7 3 2,9 2,8 2,8 2,8 2,8 2,7 2,7 2,7 2,7 2,7 2,7 2,7 2,8min. 1 1 1,0 1 1 1,0 1 1 1,0 1,0 1 1 1,0 1 1 1,0 1 1 1,0 1,0 1,0max. 9 7 9,0 8 8 8,0 10 10 10,0 10,0 11 9 11,0 8 7 8,0 8 8 8,0 8,0 11,0

Duration of verbal act (s) avg. 3,3 3,5 3,4 3,2 3,1 3,2 3,4 3,3 3,4 3,3 3,5 3,1 3,3 2,9 3,7 3,3 2,8 3,4 3,1 3,2 3,3min. 0 0 0,0 0 0 0,0 0 0 0,0 0,0 0 0,1 0,0 0,1 0,1 0,1 0 0,2 0,0 0,0 0,0max. 11,4 16,8 16,8 12,9 13,4 13,4 12,4 22,5 22,5 22,5 12,6 19 19,0 14,5 12,7 14,5 13 12,5 13,0 14,5 22,5

Controller % of all verbal acts 47 46 46,5 45 45 45,0 46 47 46,5 46,0 44 44 44,0 44 44 44,0 45 47 46,0 45,0 45,33Duration of verbal act (s) avg. 3,6 4 3,8 3,6 3,5 3,6 3,7 3,7 3,7 3,7 4,1 3,4 3,8 3,5 4,2 3,9 3,3 3,9 3,6 3,7 3,71

Pilot % of all verbal acts 53 54 53,5 55 55 55,0 54 53 53,5 54,0 56 56 56,0 56 56 56,0 55 53 54,0 55,0 54,67Duration of verbal act (s) avg. 3 3,1 3,1 2,9 2,8 2,9 3,2 3 3,1 3,0 3 2,8 2,9 2,5 3,3 2,9 2,4 2,9 2,7 2,8 2,91

French % of all verbal acts 45 23 34,0 21 19 20,0 13 31 22,0 25,3 54 74 64,0 82 30 56,0 62 54 58,0 57,0 42,33Duration of verbal act (s) avg. 2,9 3,2 3,1 2,9 3 3,0 3,2 3 3,1 3,0 3,2 2,9 3,1 2,8 3,6 3,2 2,7 3,3 3,0 3,1 3,06

English % of all verbal acts 55 77 66,0 79 81 80,0 87 69 78,0 74,7 46 26 36,0 18 70 44,0 38 46 42,0 43,0 57,67Duration of verbal act (s) avg. 3,6 3,6 3,6 3,3 3,1 3,2 3,5 3,5 3,5 3,4333 3,8 3,4 3,6 3,3 3,8 3,6 3 3,4 3,2 3,375 3,44

ARR ALL EnR

En-route sectors UIR Ext. UIR Border UIR

Table 8-1: Summary of VOCALISE Voice Statistics

----------- END OF SECTION -----------




9. Data Link Communications Profiles

This chapter represents “per aircraft” data link communication profiles as applicable today or in the near future in European en-route, TMA and airport airspace. For further detailed information we refer to [ATN_Project].

For the estimation of the number of exchanged data link messages in 2005 for LINK2000+ the following assumptions have been made (Appendix A of [ATN_Project]) for a typical flight in European Core Area:

Duration: 1,5 hours.

Sectors involved: 8 sectors (incl. TMAs)

FIRs involved: 2 or 3 (TB checked)

FL 350

Use of LACK

AOC traffic is not considered

Existing ground-ground connections (e.g. OLDI) assumed

Data link is assumed to be available only on the airports and in upper airspace

9.1. Message Volumes for ATS Services

Following tables present messages and data volumes for a typical flight based on information available in [ATN_Project]. Table 9-1 which is based on the data from [ATN_Project] lists the data link services that are expected to be used by the flight and also shows the number of times the service will be invoked during the flight.

DLIC (Data Link Initiation Capability), same as DLL (Data Link Logon)

FLIPCY (Flight Plan Consistency check)

D-ATIS (Datalink ATIS service)

DCL (Departure Clearance service)

ACM (ATC Communications Management service)

ACL (ATC Clearances and Information service)

CAP (Controller Access Parameters service)

Table 9-1 shows per-flight profiles for ATS messages that are expected to be successively5 deployed in European airspace from 2005 on. The table shows operational data link services, ATN application (CM, CPDLC, FIS, ADS) that is used by a given service, number of service invocations during a typical flight, number (No) of UL/DL messages that have to be sent for one service invocation, as well as total UL/DL data volume (Size) including all messages of a given service.

5 Ongoing LINK2000+ programme will initially implement a sub-set of these services.




Uplink Messages

Downlink Messages

Service ATN Appl.

Note Invocations per Flight

No Size (octets)

No Size (octets)

DLIC CM 1 per FIR 1 per ACC 3 5 561 5 674

FLIPCY ADS 1 per FIR 1 per ACC 3 3 531 3 744

D-ATIS FIS 2 7 759 5 443

DCL CPDLC LACKs required 1 3 278 3 249

ACM CPDLC LACKs required 7 18 1,798 18 1,328

ACL CPDLC LACKs required 16 35 3,241 35 3,150

CAP (P) ADS 16 16 2,880 288 30,768

Totals 48 87 10,048 357 37,356

Table 9-1: Total ATS Uplink/Downlink Traffic

Note: The uplink/downlink message sizes in Table 9 1 have been obtained from Table 9-2… Table 9-14. There is no general simple formula that could be used for all services.

Following tables (Table 9-2 … Table 9-14) in this section provide supplementary information about the detailed structure and size of data link messages associated with a particular ATS data link service.

The column “Ref” denotes the corresponding section of [ATN_Project], the column labelled APDU refers to the size (octets) of the Application Layer Protocol Data Unit.

The size of each APDU message depends on its parameters and is described in detail in chapter 5 of [ATN_Project]. In order to get the total size of a given message (Uplink and Downlink columns) at the sub-network boundary, 72 octets (transport/network layer overhead) have to be added to the APDU of each message.

Transport 9 octets (see 5.9.1 of [ATN_Project]

Network 63 octets (see 5.9.2 of [ATN_Project]

Following notes apply to Table 9-2 … Table 9-14:

CM Contact service is used only twice (not used in the 3rd FIR)

Total ATIS UL/DL data volumes in Table 9-1 are derived from the sum of Departure ATIS and Arrival ATIS “Uplink”/”Downlink” columns

For the ACM service, it has been assumed that there will be a total of four internal transfers, two from “Current ACC” to other FIR and two from “Next ACC” to other FIR.

In calculating the overall message volumes for the ACL service, a mixture of 9 different scenarios have been considered in [ATN_Project] section 5.6.1 (only three are shown in this document, in Table 9-10, Table 9-11 and Table 9-12, respectively).

Total periodic CAP service Data Volume: UL = 16 exchanges * 180, DL = 16 * 1923.




Total event CAP service Data Volume: UL = 16 exchanges * 184, DL = 16 exchanges * 833

CM/DS Message Ref APDU Uplink Downlink

CM Logon Request 5.8.1.4 96 - 168

CM Logon Response 5.8.1.4 33 105 -

CM Contact Request 5.8.1.4 51 123 -

CM Contact Response 5.8.1.4 13 - 85

Totals: 228 253

Table 9-2: DLIC Data Volume Exchanged per FIR

ADS/DS Message Ref APDU Uplink Downlink

ADS Demand Request 5.8.1.4 28 100 -

ADS Demand Report 5.8.2 99 - 171

D-END Request 5.8.1.4 5 77 -

D-END Response 5.8.1.4 5 - 77

Totals: 177 248

Table 9-3: FLIPCY Data Volume Exchanged per FIR

FIS/DS Message Ref APDU Uplink Downlink

FIS Demand Request 5.8.1.4 32 - 104

FIS Demand Response 5.8.1.4 37 109 -

FIS Demand Report 5.8.2 30 102 -

D-END Request 5.8.1.4 5 - 77

D-END Response 5.8.1.4 5 77 -

Totals: 288 181

Table 9-4: ATIS Data Volume Exchanged with Departure FIR

FIS/DS Message Ref APDU Uplink Downlink

FIS Updated Request 5.8.1.4 32 - 104

FIS Update Response 5.8.1.4 37 109 -

FIS Report (x2) 5.8.2 30 204 -

FIS Update Cancel 5.8.2 9 - 81

FIS Update Cancel Cnf 5.8.2 9 81 -

D-END Request 5.8.1.4 5 - 77

D-END Response 5.8.1.4 5 77 -

Totals: 471 262

Table 9-5: ATIS Data Volume Exchanged with Arrival FIR

CPDLC/DS Message Ref APDU Uplink Downlink




DCL Request 5.8.2 11 - 83

Uplink LACK 5.8.2 11 83 -

DCL Delivery 5.8.2 40 112 -

Downlink LACK 5.8.2 11 - 83

DCL PAM 5.8.2 11 - 83


Totals: 278 249

Table 9-6: DCL Data Volume Exchanged with Departure FIR


VCI Message 5.8.2 49 121 -


VCI PAM 5.8.2 11 - 83


Totals: 204 166

Table 9-7: ACM Data Volume Exc. with Current ACC (Internal Transfer)


NDA Message 5.8.2 16 88 -


VCI Message 5.8.2 49 121 -


VCI PAM 5.8.2 11 - 83


CPDLC End Request 5.8.3.1 5 98 -

CPDLC End Response 5.8.3.1 5 - 83

Totals: 390 332

Table 9-8: ACM Data Volume Exc. with Current ACC (Transfer to Other FIR)


CPDLC Start Request 5.8.1.4 26 98 -

CPDLC Start Response 5.8.1.3 11 - 83

NDA Message 5.8.2 11 - 83


Totals: 101 166

Table 9-9: ACM Data Volume Exc. with Next ACC (Transfer to Other FIR)


Example 1 UM20 5.8.2 12 84 -





Example 1 DM0 5.8.2 10 - 82


Totals: 167 165

Table 9-10: ACL Data Volume Exchanged per FIR – Scenario 1


Example 2 UM215 5.8.2 12 84 -


Example 2 DM0 5.8.2 10 - 82


Totals: 167 165



Example 3 UM20 5.8.2 12 84 -


Example 3 DA0 5.8.2 10 - 82


Totals: 167 165



ADS Periodic Request 5.8.1.4 31 103 -

ADS Periodic Response

5.8.1.4 40 - 112

ADS Periodic 5.8.2 30 - 1,734

D-END Request 5.8.3.1 5 77 -


Totals: 180 1,923

Table 9-13: CAP Data Volume Exchanged – Periodic Contract


ADS Event Request 5.8.1.4 35 107 -

ADS Event Response 5.8.1.4 13 - 85

ADS Event Report GV 5.8.2 24 - 168

ADS Event Report PP 5.8.2 37 - 253

ADS Event Report AV 5.8.2 34 - 250

D-END Request 5.8.3.1 5 77 -





Totals: 184 833

Table 9-14: CAP Data Volume Exchanged – Event Contract

9.2. Message Volumes for AOC Services

This information refers to the currently used AOC services and is based on [DL_RDMP_NA] Table 2.4.2.

Application Message Size (octets)

Frequency Total per Flight (octets)

Current Applications

Out Off On In (OOOI) 40 4 per flight 160

NOATM Requests/NOTAMS 102/276 2 per flight 756

Free Text 296 1 per flight 296

Weather Request/Weather 80 2 per flight 160

Position Weather Report 261 1 per flight 261

Loadsheet Request/Loadsheet 80 1 per flight 80

Flight Status 80 Every 15 min 960

Fuel Status 40 2 per flight 80

Engine Performance Reports 100 3 per flight 300

Maintenance Items 100 1 per flight 100

Flight Plan Transfer 200 2 per flight 200

Flight Sheet Transfer (gate) 80 1 per flight 80

Flight Log Transfer (gate) 100 2 per flight 200

Total Per Flight 3629

Table 9-15: Total AOC Per-flight Data Volume

----------- END OF SECTION -----------




10. Future Air Traffic Development

10.1. Introduction

To design properly the B-VHF system in terms of capacity and performance, it is necessary to know which service classes (CoS) will be provided from which B-VHF cell and also detailed per-aircraft communications profiles.

In order to generate the realistic loading for the B-VHF system, it is also necessary to know the aircraft population within the cell that is expected for a given year in the future. The parameters defined in this section shall be used in the B-VHF WP 3 to generate an appropriate number of aircraft, dependent on the airspace type and the B-VHF cell size.

Air picture captured in the NAVSIM tool for selected En-route and TMA sectors and Heathrow Airport (2004) may be used to place a number of aircraft at defined positions within the airspace of interest. However, the main interest of the B-VHF project is in the time frame 2015 – 2025, where significantly higher air traffic figures may be expected than for 2004.

The scenarios for the simulation of the B-VHF system performance shall be aligned with the requirements captured in the B-VHF deliverable D5 ”Report on Applications Communications Requirements” [B-VHF D5]. This deliverable in turn used data from the EUROCONTROL [MACONDO] study. [MACONDO] has produced estimates about air traffic over European Core Area for the year 2015, based on another EUROCONTROL study [EUROC_ADS].

Detailed investigation of [EUROC_ADS] has shown that in some cases [MACONDO] PIAC numbers have been given for a whole HZ (e.g. HZ-1), without taking care about the number and coverage range of GSs providing the services.

In this section, the number of A/C has been calculated/tabulated that may be expected by 2015, 2020 and 2025, respectively, within a given distance “d” from the ground station centred at Brussels. The figures have been obtained by using the air traffic densities proposed in [EUROC_ADS].

10.2. [EUROC_ADS] Brief Summary

[EUROC_ADS] scenario is based on a geographical area radius 300 nm (r_NC in Figure 10-1) in which there is a ‘core area’ radius 200 nm (r_CA in Figure 10-1).

Core Area is centred on Brussels and includes five largest TMAs in Europe (Brussels, London, Frankfurt, Paris and Amsterdam). Each terminal is considered to consist of three regions, arranged as concentric circles, centred upon the position of the major airport within a terminal (Figure 10-2).

The inner most region represents the airport surface (r_AS = 5 nm), including aircraft participating in an SMGCS environment. The middle region (r_TI = 12 nm) represents the inner terminal airspace and includes aircraft at low level around the airport. The outer region (r_TO = 50 nm) represents the outer terminal airspace embracing aircraft climbing from-/descending towards the airport.

The “non-core area” of the scenario (airports and aircraft in the range 200 nm to 300 nm from Brussels) has lower density traffic, including lower density TMA traffic.




Traffic density forecast values for 2015 have been derived from EUROCONTROL forecast tools under worst case assumptions (i.e. maximum traffic growth of 3,7% per year and peak hour of a busy day in the future).

Each of five large TMAs is given a traffic density equal to projected 2015 London TMA density (London is the busiest TMA in Europe). Each large TMA is divided into an ‘inner’ and ‘outer’ area.

Aircraft is placed randomly within defined areas. Airborne aircraft traffic is spread vertical across different altitude bands. Effects concerning an aircraft entering/leaving the scenario, as well aircraft changing the FL have not been considered. Within a region, aircraft at a given altitude band are considered to move at a constant ground speed, but in random (uniformly distributed) directions.

En-Route airspace is defined to cover the entire scenario, and so will generally overlap terminal airspace. The individual regions of terminal airspace may also be defined in such a way that they overlap. The total traffic density at a given point and altitude band is the cumulative sum of the densities arising from each region overlapping that point.

In each area, the density of air traffic (single parameter) and its altitude distribution (per FL range) has been specified, based on the estimated total number of aircraft per area and the area physical size.

The [EUROC_ADS] scenario for 2015 is summarised in Table 10-1.

Table 10-1: [EUROC_ADS] Parameters

Total 2015 airborne traffic for the whole scenario (including all TMA traffic) within 200 nm from Brussels (CA) is 1356 A/C.

Total number of En-route A/C within CA (200 nm range from Brussels) is 696 A/C (at an average “en-route density” for CA).




About 132 A/C may be expected within each of five CA TMAs within 50 nm range from the major CA airport (or from the GS providing TMA services). 29 A/C are in the inner TMA (12 nm radius) and 103 A/C in the outer TMA (50 nm radius).

The density of the NC en-route traffic is assumed to be 50% of the EC density.

There are total 150 TMA aircraft in the NC area. This was calculated by applying the NC TMA traffic density to the full size of the NC area (area between the outer NC circle and the inner CA circle).

There will be about 25 moving A/C on the airport surface of each CA major airport (within 5 nm range from the GS providing Airport services)

Additional 25 moving GND aircraft are randomly distributed within the whole (CA+NC) area, with assumed overall “CA+NC” density (8,84E-5 A/C per square nm)

r_NC = 300 nm

r_CA = 200 nm

r_NC = 300 nm

Figure 10-1: Reference [EUROC_ADS] Airspace




Figure 10-2: European Core Area and non-Core Area HZs [EUROC_ADS]

E_NC_L

E_CA_M

E_CA_H

TO_CA_M

E_CA_U

E_NC_L

TI_CA_M

TO_CA_H

E_CA_L

E_NC_M

E_NC_H

E_NC_U

E_NC_M

E_NC_H

E_NC_U

r_NC=300 nm

FL 250

r_CA=200 nm

r_TO=50 nm

r_TI=12 nm

TI_CA_L ASCA

r_AS=5 nm

M

T_NC_M

T_NC_H

T_NC_L

AS_NC …. AS_NC …. AS_NC …. AS_NC

U

H

L

FL 100

FL 30




Assumed annual traffic growth rate 2015 - 2025 3,7 %Increase factor/5 years (2015-2020; 2020-2025) 1,20Ratio of parked A/C with active VHF radios to moving A/C with active VHF radios 7,00

Distance from Brussels d (nM) 5 5 12 5 12 25 50 5 12 25 50 75 100 150 200

E Area A/C per sq. Mile

Distr. per FL

Nr. of

AC


Distr. per FL

Nr. of

AC

Nr. of

AC


Distr. per FL

Nr. of

AC

Nr. of

AC

Nr. of

AC

Nr. of

AC


Distr. per FL

Nr. of

AC

Nr. of

AC

Nr. of

AC

Nr. of

AC

Nr. of

AC

Nr. of

AC

Nr. of AC

Nr. of AC

2015FL 250+ 1 E_CA_U 0,00554 0,39 0 1 4 17 38 68 153 272FL 100-250 1 TO_CA_H 0,0131 0,65 1 4 17 67 1 E_CA_H 0,00554 0,39 0 1 4 17 38 68 153 272FL 30-100 1 TI_CA_M 0,0641 0,35 2 10 1 TO_CA_M 0,0131 0,35 0 2 9 36 1 E_CA_M 0,00554 0,16 0 0 2 7 16 28 63 111FL 0-30 1 TI_CA_L 0,0641 0,65 3 19 1 E_CA_L 0,00554 0,06 0 0 1 3 6 10 23 42GND_Moving 1 AS_CA 0,318 1 25GND_Parked 1 AS_CA 2,226 1 175A/C per area within distance "d" 200 5 29 1 6 26 103 0 2 11 44 98 174 392 697TOTAL number of airborne A/C within distance "d" 6 37 66 176 230 438 920 1357

1) 2) 3)2020FL 250+ 1 E_CA_U 0,00665 0,39 0 1 5 20 46 81 183 326FL 100-250 1 TO_CA_H 0,01572 0,65 1 5 20 80 1 E_CA_H 0,00665 0,39 0 1 5 20 46 81 183 326FL 30-100 1 TI_CA_M 0,07692 0,35 2 12 1 TO_CA_M 0,01572 0,35 0 2 11 43 1 E_CA_M 0,00665 0,16 0 0 2 8 19 33 75 134FL 0-30 1 TI_CA_L 0,07692 0,65 4 23 1 E_CA_L 0,00665 0,06 0 0 1 3 7 13 28 50GND_Moving 1 AS_CA 0,3816 1 30GND_Parked 1 AS_CA 2,6712 1 210A/C per area within distance "d" 240 6 35 1 7 31 123 0 2 13 51 118 208 469 836TOTAL number of airborne A/C within distance "d" 7 44 79 209 276 524 1101 1626

2025FL 250+ 1 E_CA_U 0,00798 0,39 0 1 6 24 55 98 220 391FL 100-250 1 TO_CA_H 0,01886 0,65 1 6 24 96 1 E_CA_H 0,00798 0,39 0 1 6 24 55 98 220 391FL 30-100 1 TI_CA_M 0,0923 0,35 3 15 1 TO_CA_M 0,01886 0,35 1 3 13 52 1 E_CA_M 0,00798 0,16 0 1 3 10 23 40 90 160FL 0-30 1 TI_CA_L 0,0923 0,65 5 27 1 E_CA_L 0,00798 0,06 0 0 1 4 8 15 34 60GND_Moving 1 AS_CA 0,45792 1 36GND_Parked 1 AS_CA 3,20544 1 252A/C per area within distance "d" 288 8 42 2 9 37 148 0 3 16 62 141 251 564 1002TOTAL number of airborne A/C within distance "d" 10 54 95 252 331 631 1324 1952"E" columns allow to enable/disable ("1" / "0") contribution from the selected particular area in a worksheet1) Second large TMA - Amsterdam - appears at the distance between 75 and 100 nM from Brussels (adding its TMA traffic to the sum)2) Further two large TMAs - Paris, London - appear at the distance between 100 and 150 nM from Brussels (adding their TMA traffic to the sum)3) All five large TMAs - Brussels, Amsterdam, Paris, London, Frankfurt - lie within the distance of 200 nM from Brussels (adding their TMA traffic to the sum)

Contributing areasCA_Airport GND contribution Inner CA_TMA contribution Outer CA_TMA contribution CA_En-route contribution

Table 10-2: Number of A/C vs. Distance from Brussels




10.3. Traffic Forecast 2015/2020/2025

Apparently, the major capacity challenge for the B-VHF system design will be European Core Area (CA), including Airport surface (AS), TMA and En-route areas, as the B-VHF system will have to provide services to the highest expected absolute simultaneous number of aircraft.

Table 10-2 shows the expected number of aircraft within a hypothetic B-VHF cell centred in Brussels with radius “d” nm. It comprises contributions of aircraft moving on the airport surface, aircraft within inner TMA (<12 nm), outer TMA (<50 nm), and En-route aircraft up to the maximum range of 200 nm. The total number of airborne aircraft within a range “d” has been indicated as well.

The relatively small number of 25 GND aircraft proposed in [EUROC_ADS] for all airports within the simulation area cannot be easily justified, when compared with the 125 GND A/C located at five very large airports.

For the purposes of the B-VHF project, the following alternative estimates are proposed for GND A/C at Large Airport (LA), Airport (AT) and Airfield (AF) categories, as defined in Chapter 12 of this document:

3 moving GND A/C per each Large Airport (LA)

0,5 moving GND A/C per each Airport (AT)

0,05 moving GND A/C per each Airfield (AF)

These figures yield about 75 GND moving A/C within 200 nm circle centred at Brussels.

Ground vehicles and static (parked - not moving) aircraft were not included in the [EUROC_ADS] scenario, however, such stationary A/C must be considered during capacity/performance evaluation, as it may participate in voice/data communications.

NOTE: Both parked A/C and A/C moving on the airport surface (already being under ATC control) can use AOC voice- and data link communications.

For the purposes of the B-VHF performance evaluation, it was assumed (Table 10-2) that the number of parked A/C on a Very Large Airport in European Core Area (e.g. Heathrow) with activated VHF radios (ready for communication, w/o respect whether actually communicating or not) is 175 - seven times the number of “moving” A/C (25) with engines running (w/o respect whether actually communicating or not).

The same parked/moving ratio has been used for other airport categories (LA, AT, AF).

Table 10-2 is separated in three areas, for the years 2015, 2020 and 2025, respectively. While the values for the year 2015 have been directly derived from [EUROC_ADS], parameters for the years 2020 and 2025 have been obtained by applying air traffic growth hypothesis.

For B-VHF purposes it was assumed that between 2015 and 2025 annual traffic growth rate of 3,7% applies in all airspace types.

This represents the worst-case hypothesis, as in the most airspace types the realistic expectation is below 3.7% per year.

NOTE: [EUROC_ADS] indicates that there is a decreasing long-time trend with respect to expected average annual growth rates in Europe (both high- and low-scenarios). In example, the annual high-hypothesis was 5,9% by 2000, while now no more




than 3,5% are expected for the period 2010–2015. Additionally, [EUROC_ADS] has been produced 2000, so it did not consider effects of September the 11th.

10.4. Airborne User Topology (2015 - 2025)

While performing B-VHF simulations, an appropriate number of aircraft shall be generated for the corresponding airspace by the target year, to make sure that performance and capacity requirements (derived from [MACONDO] study) can be fulfilled by the B-VHF system.

The “baseline” traffic picture for 2004 captured in NAVSIM tool comprises 2004 aircraft population flying over defined trajectories defined by the CFMU (flight plan-) data. This baseline population shall be used for all future scenarios. In order to obtain realistic situation by 2015 and beyond, additional “virtual” aircraft shall be generated, with associated trajectories. Assuming 3,7% annual traffic growth, the number of such virtual aircraft by 2025 will roughly correspond to the baseline NAVSIM figure for 2004.

In order to keep the model as simple as possible, it is proposed to select for the “virtual” aircraft an appropriate number of existing NAVSIM trajectories for the baseline 2004 population, but to trigger such “virtual” flights with appropriate time offset with respect to baseline ones. This means that by 2025 each baseline flight will generate another one offset flight. By 2015 only a sub-set of baseline flights will be “cloned”.

The total number of aircraft for all future scenarios, including the baseline population and “virtual” aircraft, shall be as defined in Table 10-2.

10.5. Equipage (2015 and 2020+)

The rate of B-VHF equipage will depend on many factors, including the overall introduction policy (voluntary or mandated equipage) that is yet TBD by the end of the B-VHF project. It may be possible that the whole population will be ported to the B-VHF system, with maximum demands in the terms of capacity and performance. However, it may also be possible that B-VHF system be initially introduced at higher flight levels, thus comprising only a part of the airborne population.

In order to obtain indicators about the equipage impact onto B-VHF system performance, it is proposed to perform the B-VHF system simulation by assuming several equipage hypotheses:

Low (25% of aircraft population equipped with B-VHF system)

Medium (50% aircraft equipped)

High (75% aircraft equipped)

Full (100% equipage)

NOTE: The detailed simulation scenarios (TBD in the WP 3) shall allow for the activation/de-activation of each single aircraft, thus the above requirement will be easily fulfilled.




10.6. Specific Traffic Situation in the UK

Based upon NATS Traffic Forecasts, between sixty-three (Base Case) and one hundred and sixteen (High Case) extra aircraft per hour are expected in the LTMA by 2017; an increase of between 25% and 47%.

NOTE: This corresponds to the annual growth between 2 and 3%. The value of 3,7% proposed in this section for the modelling of the B-VHF system will provide the maximum number of air traffic, and thus the “worst case”.

Since capacity gains from sectorisation will have been all but exhausted, existing airspace routings and sector infrastructure will be unable to absorb the traffic generated by the extra runways and will require a significant degree of redesign. Increased systemisation will be the primary focus of developments. Traffic density in the Southeast, combined with the geographical limits of controlled airspace, may therefore mean that new technologies and procedures must be developed. A significant element of future work in this area will involve leverage of existing technology and industry developments to deliver enhanced system capacity by reducing controller workload on a per-flight basis and hence increase system capacity.

Figure 10-3: TMA Traffic Forecast to 2017

Figure 10-4: UK Movements

050

100150200250300350400

ATMs per hour

2004 2005 2007 2012 2017

TMA Traffic Forecast to 2017

TMA BaseTMA High




10.6.1. Implementation

The Concept of Operations for 2020 is stretching and in many areas requires significant change from the ‘today’ operation. Whilst strategies and implementation plans are not considered here in detail, structural change to the existing ATC operation would have to be on an incremental basis, the end-state resulting from a large number of constituent steps.

10.6.2. Technology

The operational concept recognises that technology alone is not a solution unto itself. However, emerging technologies may be capable of expanding the possibilities for more efficient and environmentally sustainable flight operations by supporting a variety of system designs, implementation options and configurations.

----------- END OF SECTION -----------




11. Scenarios of Future Data Service Development

The purpose of this chapter is to develop scenarios and estimate the data volume of ATM/ATC/AOC applications and their communication requirements in the years 2015, 2020 and 2025.

For the development of the scenarios statistical data from [B-VHF D5] and [AATT_2015] have been used and compared. The first reference has captured European data link requirements for the year 2015, while the second reference describes specific USA needs within the same time frame.

11.1. Estimation of Data Protocol Overhead

In this section data link protocols overhead of ATN and IP are estimated.

[B-VHF D5] proposes additional 19 octets to the application message size as ATN protocol overhead.

40 bytes can be assumed as IP protocol overhead.

11.2. ATS Data-Link Services

11.2.1. European Scenario for 2015 [B-VHF D5]

This section deals with data link per–flight profiles and statistical parameters for the simulation of the B-VHF system performance by the year 2015. Later on (chapter 11.2.4), these profiles are extrapolated to the years 2020 and 2025 by applying a hypothesis about future evolution of data link services beyond 2015.

Table 11-1 has been taken from [B-VHF D5], however, original [B-VHF D5] Table 4-3 has been modified - columns not relevant for a typical per-flight profile (PIAC, Service Examples, Qualitative Throughput) have been removed.

The meaning of the particular column of Table 11-1 is as follows [B-VHF D5]:

Mean Duration: Flight duration in a given HZ (min). In Table 11-1 it is only shown for HZ1, HZ3 and HZ5 which are the most challenging zones for the B-VHF project.

95%/99,996% Time Delay: One-way end-to-end message transfer time that is achieved for the given percentage of all (user-) messages.

Priority: Communications priority, indicating the importance of expedited handling of information in the nodes of the communications system. Ranges from 1 (distress, indicating an imminent danger) to 7 (lowest priority).

Coverage: N/A = Not Applicable to that HZ, AFP = All Flight Phases, AP/S = Airport Surface or a range expressed in Nautical Miles (nm).

Access Control: C/M/A/D means that the protection against Copying/Modifying/Addition/Deletion of data (messages), respectively, is required.

Data Integrity: Max/Med/Min, meaning that loss or corruption of data is unacceptable/conditionally_acceptable/acceptable, respectively.

Residual Error Rate (RER): RER is an alternative measure of integrity, as the ratio of lost-, duplicated- or corrupted messages to the total number of messages




transmitted. The RER is measured at the VHF sub network interface and is a function of the error detection and control provisions built into the communications protocols.

Mean Time Between Failures (MTBF): An average length of time between unplanned service failures.

Mean Time To Repair (MTTR): Average duration of service outage that is acceptable.

Availability: MTBF/ (MTBF + MTTR)

Frequency per Flight: This parameter is related to the number of service transactions for the considered data link service in the Homogenous Zone (one transaction may comprise several uplink and downlink messages)6 .

Uplink and downlink size parameter presents the size of the application messages exchanged per service transaction on uplink and downlink, respectively, without data link encoding or ATN overhead

UL (bytes): Min/95% max. size of the uplink messages exchanged per transaction

DL (bytes): Min/95% max. size of the downlink messages exchanged per transaction

Additional columns have been added to the original [B-VHF D5] Table 4-3:

Domain, as specified in [AATT_2015]. “En-Route” domain is mapped onto HZ1/HZ2, “Terminal” onto HZ3/HZ4 and “Airport” onto HZ5/HZ6.

UL/DL Frequency per Minute, calculated (only-) for HZ1, HZ3 and HZ5 by dividing “UL/DL Frequency per Flight” parameter by the “Mean Duration” value (flight duration per HZ1/HZ3/HZ5). Reciprocal value of the “UL/DL Frequency per Minute” parameter corresponds to the average time (min) between successive invocations of UL/DL messages for a given service.

6 In Table 11-1 there are two separate columns (“UL Frequency per flight”, “DL Frequency per flight”), each having the same value as the (single-) “Frequency per flight” column in [B-VHF D5] Table 4-3 (that was applicable to both UL and DL messages).




Do

mai

n

HZ

Mea

n Du

ratio

n (m

inut

es)

CoS

Serv

ice

Type

95%

Tim

e De

lay

(s)

99,9

96%

Tim

e De

lay

(s)

Cove

rage

Prio

rity

Data

Inte

grity

Acce

ss C

ontro

l

RER

(10^

)

Sing

le M

TBF

(day

s)

Tota

l MTB

F (d

ays)

MTT

R (m

inut

e)

Tota

l Sys

tem

Av

ail.

(%)

UL F

requ

ency

per

fli

ght

UL (b

ytes

)

Freq

uenc

y pe

r m

in

DL F

requ

ency

per

fli

ght

DL (b

ytes

)

Freq

uenc

y pe

r m

in

Peak

Thr

ough

put

per A

/C (o

/s)

HZ-1 40 2 5 AFP+AP/S 1 Max C,M,A,D -8 1000 1,4 0,1 99,995 1/year 20 1/year 40 20HZ-2 2 5 AFP+AP/S 1 Max C,M,A,D -8 1000 2,3 0,1 99,997 1/year 20 1/year 40 20HZ-3 17 2 5 AFP+AP/S 1 Max C,M,A,D -8 1000 9,7 0,1 99,999 1/year 20 1/year 40 20HZ-4 2 5 AFP+AP/S 1 Max C,M,A,D -8 1000 50 0,1 99,9999 1/year 20 1/year 40 20HZ-5 10 2 5 AFP+AP/S 1 Max C,M,A,D -8 1000 40 0,1 99,9998 1/year 20 1/year 40 20HZ-6 2 5 AFP+AP/S? 1 Max C,M,A,D -8 1000 0,1 20 40 20HZ-1 40 5 15 AFP+AP/S 2 Max C,M,A,D -8 1000 1,4 0,5 99,976 11 45 0,28 11 30 0,28 25HZ-2 5 15 AFP+AP/S 2 Max C,M,A,D -8 1000 2,3 0,5 99,985 6 45 6 30 25HZ-3 17 5 15 AFP+AP/S 2 Max C,M,A,D -8 1000 9,7 0,1 99,999 5 45 0,29 5 30 0,29 25HZ-4 5 15 AFP+AP/S 2 Max C,M,A,D -8 1000 50 0,1 99,9999 5 45 5 30 25HZ-5 10 N/A 0,00 0,00HZ-6 N/AHZ-1 40 10 20 AFP+AP/S 3 Max C,M,A,D -7 100 0,1 0,5 99,759 30 50 0,75 30 40 0,75 12HZ-2 10 20 AFP+AP/S 3 Max C,M,A,D -7 100 0,2 0,5 99,849 19 45 19 40 12HZ-3 17 10 20 AFP+AP/S 3 Max C,M,A,D -7 100 1 0,5 99,964 17 45 1,00 17 40 1,00 12HZ-4 10 20 AFP+AP/S 3 Max C,M,A,D -7 100 5 0,5 99,9931 12 45 12 40 12HZ-5 10 10 20 AFP+AP/S 3 Max C,M,A,D -7 100 4 0,5 99,9913 8 55 0,80 8 35 0,80 10HZ-6 10 20 AFP+AP/S 3 Max C,M,A,D -7 100 4 0,5 99,991 8 55 8 35 10HZ-1 40 30 60 AFP+AP/S 7 Max M,A,D -6 100 0,1 1,5 99,28 5 50 0,13 5 30 0,13 5HZ-2 30 60 AFP+AP/S 7 Max M,A,D -6 100 0,2 1,5 99,549 2 50 2 30 5HZ-3 17 30 60 AFP+AP/S 7 Max M,A,D -6 100 1 1,5 99,893 2 50 0,12 2 30 0,12 5HZ-4 30 60 AFP+AP/S 7 Max M,A,D -6 100 5 1,5 99,9792 2 50 2 30 5HZ-5 10 30 60 AFP+AP/S 7 Max M,A,D -6 100 4 1,5 99,974 3 50 0,30 3 30 0,30 5HZ-6 30 60 AFP+AP/S 7 Max M,A,D -6 100 4 1,5 99,974 3 50 3 30 5HZ-1 40HZ-3 17HZ-5 10

En-Route

Terminal

5

D1-4

D2

Aiport

D1-2

D1-3

Pilot-Controller Emergency Dialog

Pilot-Controller Tactical Dialog

Pilot-Controller Strategic Dialog

D1-1

Pilot-Controller Information Dialog

15 25 nmPilot-Pilot Dialog C,M,A,D -82 Max 1000 0,1 RES.

En-Route

Terminal

Aiport

En-Route

Terminal

Aiport

En-Route

Terminal

Aiport

En-RouteTerminal

Aiport




Do

mai

n

HZ

Mea

n Du

ratio

n

CoS

Serv

ice

Type

95%

Tim

e De

lay

(s)

99,9

96%

Tim

e De

lay

(s)

Cove

rage

Prio

rity

Data

Inte

grity

Acce

ss C

ontro

l

RER

(10^

)

Sing

le M

TBF

(day

s)

Tota

l MTB

F (d

ays)

MTT

R (m

inut

e)

Tota

l Sys

tem

Av

ail.

(%)

ULFr

eque

ncy

per

fligh

t

UL (b

ytes

)

UL F

reuq

ency

per

M

inut

e

DL F

reuq

ency

per

Fl

ight

DL (b

ytes

)

DL F

reuq

ency

per

M

inut

e

Peak

Thr

ough

put

per A

/C (o

/s)

HZ-1 40 30 60 AFP 7 Max M,A -6 100 0,1 1,5 99,28 4 45 0,100 4 50 0,100 5HZ-2 30 60 AFP 7 Max M,A -6 100 0,2 1,5 99,549 3 45 3 50 5HZ-3 17 30 60 AFP 7 Max M,A -6 100 1 1,5 99,893 3 50 0,176 3 50 0,176 5HZ-4 30 60 AFP 7 Max M,A -6 100 5 1,5 99,9792 2 50 2 45 5HZ-5 10 30 60 AFP+AP/S 7 Max M,A -6 100 4 1,5 99,974 1 50 0,100 1 40 0,100 5HZ-6 30 60 AFP+AP/S 7 Max M,A -6 100 4 1,5 99,974 1 50 1 40 5HZ-1 40 30 60 AFP 7 Max M,A -6 100 0,1 1,5 99,28 2 175 0,050 2 45 0,050 10HZ-2 30 60 AFP 7 Max M,A -6 100 0,2 1,5 99,549 2 175 2 45 10HZ-3 17 30 60 AFP 7 Max M,A -6 100 1 1,5 99,893 2 175 0,118 2 45 0,118 10HZ-4 30 60 AFP 7 Max M,A -6 100 5 1,5 99,9792 2 175 2 45 10HZ-5 10 30 60 AFP+AP/S 7 Max M,A -6 100 4 1,5 99,974 2 175 0,200 2 45 0,200 10HZ-6 30 60 AFP+AP/S 7 Max M,A -6 100 4 1,5 99,974 2 175 2 45 10HZ-1 40 30 60 AFP 4 Max M,A,D -7 1000 1,4 0,5 99,976 1 500 0,025 1 15 0,025 15HZ-2 30 60 AFP 4 Max M,A,D -7 1000 2,3 0,5 99,985 0 500 0 15 15HZ-3 17 30 60 N/A 4 Max M,A,D -7 1000 0,5 500 0,000 15 0,000 15HZ-4 30 60 AFP 4 Max M,A,D -7 1000 50 0,5 99,9993 1 500 1 15 15HZ-5 10 N/A 0,000 0,000HZ-6 N/AHZ-1 40 30 60 AFP 4 Max M,A,D -7 1000 1,4 0,5 99,976 15 500 0,375 15 35 0,375 20HZ-2 30 60 AFP 4 Max M,A,D -7 1000 2,3 0,5 99,985 15 500 15 35 20HZ-3 17 N/A 0,000 0,000HZ-4 N/AHZ-5 10 30 60 AFP+AP/S 4 Max M,A,D -7 1000 40 0,5 99,9991 1 530 0,100 1 50 0,100 20HZ-6 30 60 AFP+AP/S 4 Max M,A,D -7 1000 40 0,5 99,999 1 530 1 50 20

En-RouteD3-1 Medium Flight

Information Exchanges

Terminal

Aiport

En-RouteD3-2 Large Flight

Information Exchanges

Terminal

Aiport

En-RouteD4-1 ATM Tactical

Exchanges

Terminal

Aiport

En-RouteD4-2 ATM Strategic

Exchanges

Terminal

Aiport




Do

mai

n

HZ

Mea

n Du

ratio

n (m

inut

es)

CoS

Serv

ice

Type

95%

Tim

e De

lay

(s)

99,9

96%

Tim

e De

lay

(s)

Cove

rage

Prio

rity

Data

Inte

grity

Acce

ss C

ontro

l

RER

(10^

)

Sing

le M

TBF

(day

s)

Tota

l MTB

F (d

ays)

MTT

R (m

inut

e)

Tota

l Sys

tem

Av

ail.

(%)

UL F

requ

ency

per

fli

ght

UL (b

ytes

)

Freq

uenc

y pe

r M

inut

e

DL F

requ

ency

per

Fl

ight

DL (b

ytes

)

Freq

uenc

y pe

r M

inut

e

Peak

Thr

ough

put

per A

/C (o

/s)

HZ-1 40 2 5 AFP(range?) 2 Max M,A -8 1000 1,4 0,1 99,995 615 0 615 30 15,38 20HZ-2 2 5 AFP(range?) 2 Max M,A -8 1000 2,3 0,1 99,997 615 0 615 30 20HZ-3 17 2 5 AFP(range?) 2 Max M,A -8 1000 9,7 0,1 99,999 665 0 665 30 20HZ-4 2 5 AFP(range?) 2 Max M,A -8 1000 50 0,1 99,9999 470 0 470 30 20HZ-5 10 N/A 0HZ-6 N/AHZ-1 40 30 60 AFP+AP/S 4 Max C,M,A -7 100 0,1 1 99,519 47 0 47 35 1,175 2HZ-2 30 60 AFP+AP/S 4 Max C,M,A -7 100 0,2 1 99,699 47 0 47 35 2HZ-3 17 30 60 AFP+AP/S 4 Max C,M,A -7 100 1 1 99,929 23 0 23 35 1,353 2HZ-4 30 60 AFP+AP/S 4 Max C,M,A -7 100 5 1 99,9861 15 0 15 35 2HZ-5 10 30 60 AFP+AP/S 4 Max C,M,A -7 100 4 1 99,9826 13 0 13 35 1,3 2HZ-6 30 60 AFP+AP/S 4 Max C,M,A -7 100 4 1 99,982 13 0 13 35 2HZ-1 40 5 15 AFP 4 Max M,A,D -7 100 0,1 1 99,519 240 22272 6 240 0 4460HZ-2 10 20 AFP+AP/S 4 Max M,A,D -7 100 0,2 1 99,699 240 13920 240 0 1400HZ-3 17 3 5 AFP+AP/S 4 Max M,A,D -7 1000 9,7 0,5 99,996 340 3296 20 340 0 1100HZ-4 3 5 AFP+AP/S 4 Max M,A,D -7 1000 50 0,5 99,9993 240 640 240 0 220HZ-5 10 1 3 AFP+AP/S 4 Max M,A,D -7 1000 40 0,5 99,9991 400 800 40 400 0 800HZ-6 1 3 AFP+AP/S? 4 Max M,A,D -7 1000 0,5 25*Nr. A/C 0 25*Nr. A/CHZ-1 40 5 15 AFP+AP/S? 4 Max M,A,D -7 100 0,1 1 99,519 240 0 6 240 20 20HZ-2 10 20 AFP+AP/S 4 Max M,A,D -7 100 0,2 0,5 99,849 240 0 240 20 20HZ-3 17 2 5 AFP+AP/S 4 Max M,A,D -7 1000 9,7 0,5 99,996 340 0 20 340 20 20HZ-4 2 5 AFP+AP/S 4 Max M,A,D -7 1000 50 0,5 99,9993 240 0 240 20 20HZ-5 10 1 3 AFP+AP/S 4 Max M,A,D -7 1000 40 0,5 99,9991 400 0 40 400 20 20HZ-6 1 3 AFP+AP/S? 4 Max M,A,D -7 1000 0,5 0 32 30

En-RouteD5-1 Dow nlink of

Tactical Aircraft Data

Terminal

Aiport

En-RouteD5-2 Dow nlink of

Strategic Aircraft Data

Terminal

Aiport

En-RouteD6-1 Ground to Air

Surveillance Broadcast

Terminal

Aiport

En-RouteD6-2 Air Surveillance

Broadcast

Terminal

Aiport

Table 11-1: Data Link Scenarios (2015) from [B-VHF D5]




11.2.2. USA Scenario for 2015 [AATT_2015]

11.2.2.1. Aircraft Classes and Domains

In order to compare scenarios for the data link capacity/performance simulations defined in [B-VHF D5] with USA-specific scenarios, an additional reference [AATT_2015] has been used.

Following aircraft classes (Table 11-2) have been defined in [AATT_2015]:

Class of Aircraft Definition and Comment

Class 1 Operators who are required to conform to FAR Part 91 only, such as low-end General Aviation (GA) operating normally up to 10,000 ft. This class includes operators of Rotorcraft, gliders, and experimental craft and other user desiring to operate in controlled airspace below 10,000 ft. The primary distinguishing factor of this class is that the aircraft are smaller and that the operators tend to make minimal avionics investments.

Class 2 Operators who are required to conform to FAR Parts 91 and 135, such as air taxis and commuter aircraft. It is likely that high-end GA and business jets and any other users desiring to operate in controlled airspace will invest in the necessary avionics to be able to achieve the additional benefits.

Class 3 Operators who are required to conform to FAR Parts 91 and 121, such as Commercial Transports. This class includes passenger and cargo aircraft and any other user desiring to operate in controlled airspace. These users will invest in the avionics necessary to achieve the additional benefits.

Table 11-2: Aircraft Classes [AATT_2015, Table 4.1-3]

Three [AATT_2015] domains (Airport, Terminal, En-Route) have been mapped (Table 11-3) to the Homogenous Zones (HZs) defined in [ATM_Context] and [B-VHF D5].

NOTE: Only the most challenging European zones, HZ1, HZ3 and HZ5 have been considered when producing scenarios for B-VHF simulations within this section.

[AATT_2015] Domain [B-VHF D5] HZ Radius Flight Level Range

Airport HZ 5 0 – 12 nm GND_Parked

GND_Moving

FL 0 – FL 30

Terminal HZ 3 0 – 50 nm FL 0 – FL 30

FL 30 – FL 100

FL 100 – FL 250

En Route HZ 1 0 – 200 nm FL 0 – FL 30

FL 30 – FL 100

FL 100 – FL 250

Table 11-3: Mapping of [AATT_2015] Domains to [B-VHF D5] HZs




11.2.2.2. Mapping of [AATT_2015] Messages onto CoS Classes

[AATT_2015] assumes that any A/G data link message may be associated with one of 9 so called “technical concepts”, each having its specific requirements upon functional capabilities and architecture of the underlying communication system.

Table 11-4 addresses percentage of aircraft equipped for each such technical concept by 2015 [AATT_2015, Table 4.1-4]. The original table has been supplemented by the column “B-VHF CoS” with the proposed mapping of [AATT_2015] technical concepts onto classes of service (CoS) defined in [B-VHF D5].

Technical Concept Class 1 Class 2 Class 3 B-VHF CoS

FIS (Flight Information Service) 52% 74% 79% CoS D 3

TIS (Traffic Information Service) 53% 65% 90% CoS D 6-1

CPDLC (Controller Pilot Data Link Communication)

48% 76% 98% CoS D 1

CPC (voice) (Controller Pilot Communication) 100% 100% 100% N/A7

DSSDL (Decision Support System Data Link) 10% 34% 70% CoS D 4

AOCDL (Airline Operational Control Data Link) N/A 5% 51% CoS D-AOC8

ADS Reporting (Automated Dependent Surveillance Reporting)

53% 65% 90% CoS D 6-2

AUTOMET (Automated Meteorological Transmission)

52% 74% 79% CoS D 59

APAXS (Aeronautical Passenger Service) 2% 3% 46% N/A10

Table 11-4: Aircraft Equipage Levels [AATT_2015, Table 4.1-4]

Table 11-5 shows the proposed detailed mapping of AATT message types onto [B-VHF D5] Classes of Services (CoS) where table 3.1-5 from [AATT_2015] is used as baseline.

Message Category

Msg. ID

Message Type CoS Class

FIS M13 Arrival ATIS

M15 Convection

M17 Departure ATIS

M18 Destination Field Condition

M20 En Route Backup Strategic General Imagery

D 3

7 CPC does not deal with data link, but has been retained here for the purpose of completeness. 8 CoS D-AOC has not been specified in MACONDO, but has been added within the B-VHF project to include AOC data link. 9 In Europe, there may be more services of that type (e.g. Downlink of Aircraft Parameters), as required by the European concept of enhanced surveillance. 10 APAXS - which is APC (Aeronautical Passengers Communications) - is currently not allowed in VHF-COM band and is not required in [B-VHF D5].




M21 FIS Planning – ATIS

M22 FIS Planning Service

M26 General Hazard

M27 Icing

M28 Icing/ Flight Conditions

M29 Low Level Wind Shear

M35 Radar Mosaic

M37 Surface Conditions

M38 TFM Information

M39 Turbulence

M40 Winds/ Temperature

TIS M3 Air Traffic Information D 6-1

CPDLC M24 Flight Plans

M29 Low Level Wind Shear

M32 Pilot/Controller Communications

M33 Position Reports

M34 Pre-Departure Clearance

M41 System Management Control

D 1

DSSDL M2 Advanced ATM

M16 Delivery of Route Deviation Warnings

M24 Flight Plans

D 4

AOCDL M9 Airline Maintenance Support: In-Flight Emergency Support

M10 Airline Maintenance Support: Non-Routine Maintenance/ Information

M11 Airline Maintenance Support: On-Board Trouble Shooting

M12 Airline Maintenance Support: Routing Maintenance/ Information Reporting

M19 Diagnostic Data

M23 Flight Data Recorder Downlinks

M25 Gate Assignment

M30 Out/ Off/ On/ In

M8 Airline Maintenance Support: Electronic Database Updating

D-AOC

ADS-B M1 ADS D 6-2

AUTOMET M43 Aircraft Originated Ascent Series Meteorological Observations

M44 Aircraft Originated Descent Series Meteorological Observations

D 5

Table 11-5: [AATT_2015] Message Mapping onto [B-VHF D5] CoS Classes




11.2.2.3. ATS Data Link Scenario [AATT_2015]

Table 11-6: Class 3 Data Link Profile - [AATT_2015] Table 4.3-5




The data link scenario described in this section is established by using statistical parameters from [AATT_2015] Table 4.3-5 (re-printed here as Table 11-6), and the mapping from Table 11-5. This scenario deals with data link profile for Class 3 aircraft in the USA airspace.

NOTE: Class 3 – commercial transport aircraft - is of prime interest for the B-VHF project, as it would generate the most demanding data link profile.

The original [AATT_2015] data have been further adjusted to become comparable to the European ones [B-VHF D5].

Airport/Terminal/En-route domains from [AATT_2015] have been mapped onto [MACONDO] “homogenous zones” (HZs), according to Table 11-5.

[AATT_2015] Message Types have been associated with generalized [B-VHF D5] CoS (all CoS sub-classes are now seen as one class).

D1: D1-1, D1-2, D1-3, D1-4.

D2: not applicable to [AATT_2015].

D3: D3-1 and D3-2.

D4: D4-1 and D4-2.

D5: D5-1 and D5-2.

D6: D6-1 and D6-2.

In Table 11-7 the statistical parameters are presented, including the message types derived from [AATT_2015] that have been mapped onto general [B-VHF D5] CoS classes. Additional columns that do not appear in [B-VHF D5] have the following meaning:

Message Type: Message ID, according to [AATT_2015] Table 3.1-5.

Priority: Service priority, as stated for a given technical concept in [AATT_2015] Table 4.2-1. The NAS System Requirements Specification defines priority levels as follows:

Critical services are those which, if lost, would prevent the NAS from exercising safe separation and control aircraft. For critical services the availability goal is 0.99999 and the goal service restoration time is 6 seconds.

Essential services are those which, if lost, would reduce the capability of the NAS to exercise safe separation and control of aircraft. For essential services the availability of the goal is 0.999 and the goal for service restoration time is 10 minutes.

Routine services are those which, if lost, would not significantly degrade the capability of the NAS to exercise safe separation and control of aircraft. For routine services the availability goal is 0.99 and the goal for service restoration time is 1.68 hours.

Availability: values as stated in [AATT_2015] Table 4.2-1.

Restoration time: values as stated in [AATT_2015] Table 4.2-1.

Call Setup time: values as stated in [AATT_2015] Table 4.2-1.

End-to-end Latency: values as stated in [AATT_2015] Table 4.2-1.

UL (bytes): message size in bytes for each UL message type.

DL (bytes): message size in bytes for each DL message type.




UL Total Data Volume per Flight (bytes): Total number of UL bytes within a given domain/HZ, calculated for each message type across entire flight duration within a given HZ by multiplying UL Frequency per Flight and UL (bytes) message size.

DL Total Data Volume per Flight (bytes): Total number of DL bytes within a given domain/HZ, calculated for each message type across entire flight duration within a given HZ by multiplying DL Frequency per Flight and DL (bytes) message size.

UL Frequency per Minute: Calculated for each CoS and each domain/HZ by dividing the number of UL messages (UL Frequency per Flight) by the [B-VHF D5] Mean Duration parameter ([AATT_2015] A/C dwell time within a given domain, en-route: 25 min, terminal: 10 min and airport: 10 min)11.

DL Frequency per Minute: Calculated for each CoS and each domain/HZ by dividing the number of DL messages (DL Frequency per Flight) by the [B-VHF D5] Mean Duration parameter ([AATT_2015] A/C dwell time within a given domain, en-route: 25 min, terminal: 10 min and airport: 10 min).

The rows of Table 11-7 labelled with “TOTAL” present the following values:

TOTAL UL/DL Frequency per Flight for all messages of the same CoS class within a given domain (HZ) has been calculated by summing up the UL/DL Frequency per Flight contributions (number of invocations) of each message type.

TOTAL value for UL/DL Total Data Volume per Flight for entire CoS has been calculated within a given domain by summing up per-message contributions (“UL/DL Frequency per Flight” * “UL/DL (bytes)”)

TOTAL value for UL/DL Data Volume has been divided by the TOTAL UL/DL Frequency per Flight applicable to this CoS (as calculated above) in a given HZ/domain to obtain the “TOTAL” UL/DL (bytes) for a representative message for each class that would with TOTAL UL/DL Frequency per Flight invocations produce the same data volume within a given HZ as the “real” messages.

TOTAL UL/DL Messages per Minute has been derived by dividing TOTAL UL/DL Frequency per Flight by the [B-VHF D5] Mean Duration parameter.

11.2.3. Comparison of ATS Scenarios

Finally, previous two [B-VHF D5], [AATT_2015] scenarios for the year 2015 have been summarized in Table 11-8 that allows for the comparison of statistical parameters (UL/DL Frequency per Flight, UL/DL bytes, UL/DL Data Volume, UL/DL Frequency per Minute) from [B-VHF D5] and [AATT_2015], respectively. In order to make such a comparison possible, all sub-classes of Table 11-1 have been re-combined into single data class (CoS D1 … CoS D6). The “aggregate” parameters for each [B-VHF D5] CoS have been calculated from the CoS sub-classes in the same way as the corresponding [AATT_2015] parameters were obtained, based on particular [AATT_2015] messages.

11 In [AATT_2015] the mean flight duration in each domain (HZ) is different to [B-VHF D5].




Dom

ain

HZ Mea

n D

urat

ion

CoS

Serv

ice

Type

Mes

sage

Ty

pe

Prio

rity

Avai

labi

lity

Rest

orat

ion

Tim

e

Call S

etup

tim

e

Late

ncy

End

to E

nd

UL F

requ

ency

pe

r flig

ht

UL

(bits

)

UL (b

ytes

)

UL T

otal

Dat

a Vo

lum

e (b

ytes

)

UL F

requ

ency

pe

r min

ute

DL F

reqe

ncy

per f

light

DL

(bits

)

DL (b

ytes

)

DL T

otal

Dat

a Vo

lum

e (b

ytes

)

DL F

requ

ency

pe

r min

ute

M 32 10,2 118 14,75 150,45 17,4 34 4,25M 41 6 720 90,00 540,00 4 720 90,00

Total 16,2 42,62 690,45 0,65 21,4 20,28 433,95 0,86M 32 9,6 123 15,38 13,1 32 52,40M 41 2 720 90,00 1 720 90,00

Total 11,6 28,24 327,60 1,16 14,1 10,10 142,4 1,41M 32 10 123 15,38 10 123 15,38M 34 1,25 1800 225,00 2,25 304 38,00M 41 5 720 90,00 4 720 90,00

Total 16,25 54,46 885,00 1,63 16,25 36,88 599,25 1,63M 17 1 3200 400,00 1 64 8,00M 22 240 2000 250,00 4 64 8,00M 28 1 45000 5625,00 0 0 0,00

Total 242 272,83 66025,00 9,68 5 8,00 40 0,20M 21 1 400 50,00 1 56 7,00M 22 90 2000 250,00 6 64 8,00

Total 91 247,80 22550,00 9,10 7 7,86 55 0,70Airport HZ 5 10 M 22 60 2100 262,50 1 64 8,00Total 60 262,50 15750,00 6,00 1 8,00 8 0,10

M 16 0,20 800,00 100,00 0,20 800,00 100,00M 38 1,00 800,00 100,00 1,00 100,00 12,50M 2 1,00 40,00 5,00 1,00 960,00 120,00

Total 2,20 56,82 125,00 0,09 2,20 69,32 152,50 0,09M 16 0,20 800,00 100,00 0,20 800,00 100,00M 2 1,00 40,00 5,00 1,00 960,00 120,00

M 38 0,50 800,00 100,00 0,50 800,00 100,00Total 1,70 44,12 75,00 0,17 1,70 111,76 190,00 0,17

M 16 0,20 800,00 100,00 0,20 800,00 100,00M 2 1,00 40,00 5,00 1,00 960,00 120,00

M 38 2,00 800,00 100,00 2,00 800,00 100,00Total 3,20 70,31 225,00 0,32 3,20 106,25 340,00 0,32

M 43 1 56 7,00 6,67 2152 269,00M 44 1 56 7,00 20 3544 443,00

Total 2 7,00 14,00 0,08 26,67 399,48 10654,23 1,07Terminal HZ 3 10 M 43 1 56 7,00 45 512 64,00

1 7,00 7,00 0,10 45 64,00 2880 4,50Airport HZ 5 10 N/A N/A 0 0,00 0 0 0,00Total

En-Route HZ 1 25 M 1 1 128 16,00 198 144 18,00Total 1 16,00 16,00 198 18,00 3564 7,92

Terminal HZ 3 10 M 1 1 128 16,00 168,9 144 18,001 16,00 16,00 168,9 18,00 3040,2 16,89

Airport HZ 5 10 M 1 1 128 16,00 545,5 144 18,00Total 1 16,00 16,00 545,5 18,00 9819 54,55

≤ 30sec

~ 10sec

Critical 0.99999 ≤ 5 sec ~ 1 sec

10

Routine 0.99

0.999

0.99 ≤ 10sec

~ 10sec

10

25

D3 Flight Information Exchanges Routine 1.7 hour

HZ 3 10

Airport HZ 5 10

Critical 0.99999 ≤ 5 sec ~ 10sec

6 secondsPilor ControllerTerminal

Terminal HZ 3

En-Route HZ 1

En-Route HZ 1 25

D1

HZ 1

Terminal HZ 3

25

10 ~ 1 sec

En-Route HZ 1

D5 Aircraft Data

25

Airport HZ 5

≤ 5 sec

En-Route

10 minutes

1.7 hour

6 secondsD6 Surveillance Broadcast

D4 ATM Exchanges Essential

Table 11-7: Data Link Profiles and Requirements from [AATT_2015]




Dom

ain

HZ CoS

Serv

ice

Type

Mea

n Du

ratio

n (m

in)

UL

Freq

uenc

y pe

r fli

ght

UL (b

ytes

)

UL

Dat

a Vo

lum

e (b

ytes

)

UL

Freq

uenc

y pe

r m

inut

e

DL F

reqe

ncy

per

fligh

t

DL (b

ytes

)

DL

Dat

a Vo

lum

e (b

ytes

)

DL

Freq

uenc

y pe

r m

inut

e

Mea

n Du

ratio

n (m

in)

UL

Freq

uenc

y pe

r fli

ght

UL (b

ytes

)

UL

Dat

a Vo

lum

e pe

r Flig

ht (b

yte)

UL

Freq

uenc

y pe

r M

inut

e

DL

Freq

uenc

y pe

r fli

ght

DL (b

ytes

)

DL

Dat

a Vo

lum

e pe

r Flig

ht (b

yte)

DL

Freq

uenc

y pe

r M

inut

e

En-Route HZ 1 25 16,2 42,62 690,45 0,65 21,4 20,28 433,95 0,86 40 46 48,80 2245,00 1,15 46 36,52 1680,00 1,15Terminal HZ 3 10 11,6 28,24 327,60 1,16 14,1 10,10 142,4 1,41 17 24 45,42 1090,00 1,41 24 37,08 890,00 1,41Airport HZ 5 10 16,25 54,46 885,00 1,63 16,25 36,88 599,25 1,63 10 11 53,64 590,00 1,10 11 33,64 370,00 1,10Sum 44,05 51,75 81 81En-Route HZ 1 25 242 272,83 66025,00 9,68 5 8,00 40 0,20 40 6 88,33 530,00 0,15 6 48,33 290,00 0,15Terminal HZ 3 10 91 247,80 22550,00 9,10 7 7,86 55 0,70 17 5 100,00 500,00 0,29 5 48,00 240,00 0,29Airport HZ 5 10 60 262,50 15750,00 6,00 1 8,00 8 0,10 10 3 133,33 400,00 0,30 3 43,33 130,00 0,30Sum 393 13 14 14En-Route HZ 1 25 2,20 56,82 125,00 0,09 2,20 69,32 152,50 0,09 40 16 500 8000,00 0,40 16 33,75 540,00 0,40Terminal HZ 3 10 1,70 44,12 75,00 0,17 1,70 111,76 190,00 0,17 17 0 0 0,00 0,00 0 0 0,00 0,00Airport HZ 5 10 3,20 70,31 225,00 0,32 3,20 106,25 340,00 0,32 10 1 530 530,00 0,10 1 50 50,00 0,10Sum 7,10 7,10 17 17En-Route HZ 1 25 2 7,00 14,00 0,08 26,67 399,48 10654,23 1,07 40 662 0,00 0,00 16,55 662 30,35 20095,00 16,55Terminal HZ 3 10 1 7,00 7,00 0,10 45 64,00 2880 4,50 17 688 0,00 0,00 40,47 688 30,17 20755,00 40,47Airport HZ 5 10 0,00 0,00 10 13 0,00 0,00 1,30 13 35,00 455,00 1,30Sum 3 71,67 1363 1363En-Route HZ 1 25 1 16,00 16,00 0,04 198 18,00 3564 7,92 40 240 22272 5345280,00 6,00 240 20 4800,00 6,00Terminal HZ 3 10 1 16,00 16,00 0,10 168,9 18,00 3040,2 16,89 17 340 3296 1120640,00 20,00 340 20 6800,00 20,00Airport HZ 5 10 1 16,00 16,00 0,10 545,5 18,00 9819 54,55 10 400 800 320000,00 40,00 400 20 8000,00 40,00Sum 3 912,4 980 980

D3Flight Information Exchanges

D6Surveillance Broadcast

D4ATM Exchanges

D5 Aircraft Data

Calculated Values derived from [B-VHF D5]Calculated Values derived from [AATT_2015]General Information

D1Pilot Controller

Table 11-8: Summary of [B-VHF D5] and [AATT_2015] Data Link Requirements




11.2.4. ATS Data Link Scenarios for 2020+

As no exact data could be found dealing with the future development of ATS data link services beyond 2015, 3% annual traffic growth figure is proposed in this document as a working hypothesis for all ATS CoS classes (TB verified). This value has been obtained as follows:

Total UL/DL ATS data traffic volume for a typical flight in the 2005 was calculated as a baseline, by using all non-periodic 2005 messages and UL/DL data volumes (“Size” columns) from Table 9-1 (chapter 9). The sum of all UL and DL volumes by 2005 - except for the periodic CAP (P) service - is 13756 octets.

Similarly, total UL/DL ATS data traffic volume for the year 2015 from Table 11-8 derived for the [B-VHF D5] scenario was separately calculated by summing up contributions of all “generalized” CoS. The sum of all UL and DL volumes by 2015 – excluding “periodic” classes CoS D5, CoS D6 – is 18075 bytes.

From these two values the rounded annual data traffic growth of 3% was derived and applied to all service classes when developing scenarios for the year 2020 and 2025, respectively.

NOTE: Assuming 8% annual traffic growth rate (as used for CoS D-AOC class) to be also applicable to other CoS data classes would produce more than doubled per-flight data volume by 2025 when compared with the 2015 “baseline”. Even if it is not realistic that ATS data link services would evolve at such a speed, it could be used as an alternative working hypothesis for testing the B-VHF system under “worst-case” heavy load conditions.

In each class the total number of service invocations (frequencies) per flight is calculated based on the year 2015 and then corrected to the years 2020 and 2025 by using above traffic growth hypothesis (3% annual traffic growth). The message sizes for 2015 have not been changed, only the number of service invocations per flight was corrected.

The resulting Table 11-9 shows the traffic growth independently for both studies (MACONDO and AATT) and lists “UL/DL Frequency per flight” and “UL/DL Frequency per minute” for each domain and each class.

NOTE: The values for D5 and D6 are calculated in the same way as all other classes (3% annual growth).




Dom

ain

HZ

CoS

Serv

ice

Type

Mea

n D

urat

ion

(min

)

UL F

requ

ency

per

fli

ght

UL F

requ

ency

per

M

inut

e

DL F

requ

ency

per

fli

ght

DL F

requ

ency

per

M

inut

e

UL F

requ

ency

per

fli

ght

UL F

requ

ency

per

M

inut

e

DL F

requ

ency

per

fli

ght

DL F

requ

ency

per

M

inut

e

Mea

n D

urat

ion

(min

)

UL F

requ

ency

per

fli

ght

UL F

requ

ency

per

M

inut

e

DL F

requ

ency

per

fli

ght

DL F

requ

ency

per

M

inut

e

UL F

requ

ency

per

fli

ght

UL F

requ

ency

per

M

inut

e

DL F

requ

ency

per

fli

ght

DL F

requ

ency

per

M

inut

e

En-Route HZ 1 25 18,78 0,75 24,81 0,99 21,77 0,87 28,76 1,15 40 53,33 1,33 53,33 1,33 61,82 1,55 61,82 1,55Terminal HZ 3 10 13,45 1,34 16,35 1,63 15,59 1,56 18,95 1,89 17 27,82 1,64 27,82 1,64 32,25 1,90 32,25 1,90Airport HZ 5 10 18,84 1,88 18,84 1,88 21,84 2,18 21,84 2,18 10 12,75 1,28 12,75 1,28 14,78 1,48 14,78 1,48





D1 Pilot Controller

D3Flight Information Exchanges

D6 Surveillance Broadcast

D4 ATM Exchanges

D5 Aircraft Data

[AATT_2015] --> 2025 [B-VHF D5] --> 2020 [B-VHF D5] --> 2025General Information [AATT_2015] --> 2020

Table 11-9: 2020/2025 ATS Scenarios Based on [AATT_2015] and [B-VHF D5]




11.3. AOC Data Link Services by 2015, 2020 and 2025

This section discusses two generic AOC DL profiles for the years 2015, 2020 and 2025.

One baseline profile (2005) is established by using the generic AOC DL profile of Table 2 from [DL_RDMP_NA] and Table 4-4 from [B-VHF D5]. These tables show current, near future and future AOC data link applications. Table 11-10 shows the parameters for AOC DL message sizes, as well as frequency per hour/per flight, respectively, and proposes values to be used for the definition of future AOC data link scenarios. Table 11-11 presents the mapping of AOC services into the specific domains (en-route, terminal, airport).

Another baseline profile (2015) is established by using AOCDL (D-AOC) message types from [AATT_2015]. Table 11-12 presents statistical parameters (number of message invocations in different domains and message size for the year 2015) which are taken from [AATT_2015]. Different AOC message types have already been explained in Table 11-5.

In order to make assumptions for the year 2015 and further for 2020 and 2025, the total number of message exchanges per flight for the baseline years 2005/2015, respectively, has been corrected, taking the assumed 8% annual data traffic growth rate into account.

NOTE: Lufthansa has informed the B-VHF consortium [LH_Traffic] that they internally use 8% annual growth figure when forecasting future per aircraft AOC data link traffic. This figure has been used in the following work as representative for the future development of the CoS D-AOC data link class.

Table 11-13 shows the growth of message exchanges for the years 2015, 2020 and 2025 by assuming an increased number of message invocations across the flight (according to the growth hypothesis), but keeping the same AOC message size as for 2005.

The proposed 8% annual traffic growth is also used for D-AOC values of [AATT_2015].




Application [DL_RDMP_NA] AOC Data Link Service [NEW_SAT], [ATNI-TF]

Flig

ht P

hase

[ATN

I-TF]

Ref.

Mes

sage

Size

(Byt

es)

[NEW

_SAT

]

Mes

sage

Siz

e (o

ctet

s)

[DL_

RDM

P_NA

]

Mes

sage

Size

(Byt

es)

[ATN

I-TF]

Prop

osed

Mes

sage

Siz

e (o

ctet

s)

Freq

uenc

y pe

r Hou

r [N

EW_S

AT]

Freq

uenc

y pe

r flig

ht

[DL_

RDM

P_NA

]

Tran

sact

ions

/Flig

ht [A

TNI-

TF]

Mes

sage

s/Tr

ansa

ctio

n [A

TNI-T

F]

Prop

osed

Num

ber o

f M

essa

ges

per F

light

Current Applications Current ApplicationsOut Off On In (OOOI) Movement Messages (OOOI) AP, TMA [NEW_SAT] 40 40 40 40 4 4 4 1NOTAM Request/NOTAMS NOTAM request - En-route [NEW_SAT] 260 102 / 276 276 2 2

NOTAM request - Ground [NEW_SAT] 110 110 2Free Text Free text [NEW_SAT] 300 296 300 4 1Weather Request/Weather Weather Request [NEW_SAT] 80 80 80 4 2Position Weather Report Position Weather Report ENR [NEW_SAT] 260 261 80 261 2 1 2 1Loadsheet Request/LoadSheet Loadsheet Request [NEW_SAT] 80 80 80 1 1Flight Status Flight Status ENR,TMA [NEW_SAT] 80 80 80 80 12 1/15 min 5 1Fuel Status Fuel Status ENR [NEW_SAT] 50 40 40 50 4 2 2 1Engine Performance Reports Engine Performance reports ENR [NEW_SAT] 100 100 100 100 4 3 3 1Maintenance Items Maintenance Report [NEW_SAT] 100 100 100 2 1Flight Plan Transfer Fligth Plan Transfer AP [NEW_SAT] 200 200 200 200 3 2 1 2Load Sheet transfer (gate) Load Sheet Transfer AP [NEW_SAT] 80 80 80 80 1 1 1 1Flight Log Transfer (gate) Fligth Log Transfer AP [NEW_SAT] 100 100 100 100 2 2 1 2Near Future Applications New ApplicationsReal Time Maintenance Information Real Time Maintenance Information ENR,TMA [NEW_SAT] 50 50 50 50 6 5 1 5Graphical Weather Information Graphical Weather Information ENR [NEW_SAT] 2000 2000 2000 2000 4 4 2 2Online Technical Trouble Shooting Online Trouble Shooting ENR,TMA [NEW_SAT] 500 500 500 500 5 5 0 - 1 5Real Time Weather Reports for Met OfficReal Time Weather Reports ENR [NEW_SAT] 80 26 26 80 12 180 1/3 min 1Telemedicine Telemedicine ENR [NEW_SAT] 4000 4000 4000 4000 1 8 0 - 1 8Technical Log Book Update (gate) Technical Log Book Update AP [NEW_SAT] 400 400 400 400 1 1 0 - 1 1Cabin Log Book Transfer (gate) Cabin Log book Update AP [NEW_SAT] 400 400 400 400 1 1 1 1Onboard Documentation Transfer (gate Update electronic Library AP [NEW_SAT] 4000 1000 1000 4000 1 1 0 - 1Software Loading (gate) Software Loading AP [NEW_SAT] 4000 4000 4000 4000 1 2 0 - 1 2Future Applications (2005+)Collaborative Decision Making [DL_RDMP_NA] 5000 5000 1Gatelink Applications (gate) [DL_RDMP_NA] 50000 50000 1Security Monitoring [DL_RDMP_NA] 128 128 1/sec

Table 11-10: [B-VHF D5] AOC DL Scenario




DomainMean

Duration (minutes)

AOC Service Message Size

Frequnecy per Flight

NOTAM request en-route 276 2Weather Request 80 4Position Weather Request 261 2Flight Status 80 9Fuel Status 50 4Real Time Maintenance Information 50 4Graphical Weather Information 2000 4Online Trouble Shooting 500 4Real Time Weather Report 80 12Telemedicine 4000 1Total 380 46Movement Messages (OOOI) 40 2Flight Status 80 3Real Time Maintenance Information 50 2Online Trouble Shooting 500 1Total 115 8

10 Movement Messages (OOOI) 40 2NOTAM request ground 110 2Flight Plan Transfer 200 3Load Sheet Transfer 80 1Flight Log Transfer 100 2Technical Log Book Update 400 1Cabin Log Book Update 400 1Update Electronic Library 4000 1Software Loading 4000 1Total 713 14

En-Route 40

Terminal 15

Airport

Table 11-11: [B-VHF D5] AOC Data Volumes for the Year 2005




Dom

ain

HZ

Mes

sge

Type UL

Fr

eque

ncy

per f

light

UL

(bits

)

UL (b

ytes

)

DL

Freq

ency

pe

r flig

ht

DL

(bits

)

DL (b

ytes

)

HZ 5 M11 6 480 60 6 10080 1260M12 3 480 60 3 10400 1255M25 1 10 1 1 10 1M30 1 10 1 1 10 1M8 3 480 60 3 10400 1300

HZ 3.1a Total 14 413 52 14 8779 1097HZ 3.1b M10 3 480 60 3 10400 1300HZ 3.2 M11 6 480 60 6 10080 1260

M12 3 480 60 3 5200 650M19 0 15 50 6M30 1 10 1 1 10 1M8 3 480 60 3 10400 1300M9 1 2600 325 4 240 30

HZ 3 Total 17 577 72 35 4006 501HZ 1 M11 6 480 60 6 10080 1260HZ 2 M12 3 480 60 3 10400 1300

M19 0 40 50 6M23 0 0 0 1 3000 375M8 3 480 60 3 10400 1300M9 1 2600 325 4 240 30

Total 13 643 80 57 2260 283

En-Route

Airport

Terminal

Table 11-12: AOC Data Volumes for the years 2015 [AATT_2015]

Year

/Tot

als

Dom

ain

Mea

n Du

ratio

n [B

-VHF

D5] (

min

) UL

Ave

rage

Mes

sage

Size

(byt

es)

ULFr

eque

ncy

per F

light

UL F

requ

ency

per

min

ute

DL A

vera

ge M

essa

ge

Size

(byt

es)

UL F

requ

ency

per

Flig

ht

DL F

requ

ency

per

min

ute

Mea

n Du

ratio

n

Tota

l UL

Aver

age

Mes

sage

Siz

e (b

ytes

)UL

Fre

quen

cy p

er F

light

UL F

requ

ency

per

min

ute

Tota

l DL

Aver

age

Mes

sage

Siz

e (b

ytes

)DL

Fre

quen

cy p

er F

light

DL F

requ

ency

per

min

ute

En-Route 40 380 46,0 1,2 380 46,0 1,2 25Terminal 17 115 8,0 0,5 115 8,0 0,5 10Aiport 10 713 14,0 1,4 713 14,0 1,4 10

Total 68,0 68,0En-Route 40 380 99,3 2,5 380 99,3 2,5 25 80 13 0,52 283 57 2,3Terminal 17 115 17,3 1,0 115 17,3 1,0 10 72 17 1,70 531 35 3,5Aiport 10 713 30,2 3,0 713 30,2 3,0 10 52 14 1,40 1097 14 1,4

Total 146,8 146,8 44,0 106,0En-Route 40 380 145,9 3,6 380 145,9 3,6 25 80 19,1 0,76 283 83,8 3,4Terminal 17 115 25,4 1,5 115 25,4 1,5 10 72 25,0 2,50 501 51,4 5,1Aiport 10 713 44,4 4,4 713 44,4 4,4 10 52 20,6 2,06 1097 20,6 2,1

Total 215,7 215,7 64,7 155,7En-Route 40 380 214,4 5,4 380 214,4 5,4 25 80 28,1 1,12 283 123,1 4,9Terminal 17 115 37,3 2,2 115 37,3 2,2 10 72 36,7 3,67 531 75,6 7,6Aiport 10 713 65,3 6,5 713 65,3 6,5 10 52 30,2 3,02 1097 30,2 3,0

Total 316,9 316,9 95,0 228,8

Calculated Values from [DL_RDMP_NA] Calculated Values from [AATT_2015]

Year 2005

Year 2015

Year 2020

Year 2025

General

Table 11-13: AOC forecasts for the years 2015, 2020 and 2025

----------- END OF SECTION -----------




12. Scenarios of Future Voice Service Development

The capacity/performance simulation of the B-VHF voice sub-system requires adequate voice traffic loading. The simulation will be performed for the years 2015 and 2020/2025 (TBC), respectively. This section proposes a method how to compose adequate voice profiles for different voice service classes expected by 2015 and beyond. The scenarios for the voice performance simulation will be further refined within the WP 3.

12.1. Required Cell Voice Capacity

The specific demands of different CoS classes are shown in Table 12-1. It can be seen that different service classes have different users, e.g. some services (e.g. CoS v2, CoS v5, CoS v-AOC) are selectively provided to selected A/C, while other service classes (e.g. CoS v1, CoS v2 in a multicast mode, CoS v3) are provided to the groups of aircraft (User Groups) or (CoS v4) even full A/C population found within a cell.

Service Users Nr. of Users Required Cell Capacity

CoS v1 Controller/ A/C from a User Group

n_UG Defined by the number of permanent User Groups per cell (n_UG).

CoS v2 Controller/ A/C from a User Group

n_AC Defined by the number of CoS v2 service invocations per A/C per hour (indirectly on the instantaneous number of A/C (n_AC) within a cell).

CoS v3 A/C from a User Group

n_PP Fixed - one dedicated permanent channel per cell (n_PP = 1).

CoS v4 All A/C within a cell

n_BR Defined by the number of permanent current voice broadcast services per cell (n_BR).

CoS v5 Any A/C within a cell

n_AC Defined by the number of CoS v5 service invocations per A/C per hour (indirectly on the instantaneous number of A/C (n_AC) within a cell).

CoS v-AOC Any A/C within a cell

n_AC Defined by the number of CoS v-AOC service invocations per A/C per hour (indirectly on the instantaneous number of A/C (n_AC) within a cell).

Table 12-1: Voice Service Users within the B-VHF Cell

12.1.1. CoS v1

CoS v1 class provision requires one permanently allocated voice channel per User Group, so the required cell capacity depends on the number of User Groups that should be supported per cell (n_UG). This parameter comprises the number of currently used party line channels and the future increase due to the increased number of sectors in response to the air traffic growth.

The performance simulation should indicate the required number of dedicated channels to provide guaranteed performance (voice delay, efficiency of anti-blocking mechanisms …) under a given realistic air traffic increase.

NOTE: The simulation shall start with the current number of User Groups. During the simulation, the duty-cycle within each User Group should be monitored (should




remain below 60%), eventually a creation of the new User Group should be considered!

NOTE: It is proposed to assume that the demand rate for new ATC sectors will follow the assumed rate of annual air traffic growth (3,7% per year). This will have to be balanced-out by the increased availability of B-VHF system voice channels.

12.1.2. CoS v2

Voice class CoS v2 will use on-demand voice channel that may co-exist with the channel used for CoS v1. In this case, the cell shall provide sufficient capacity for the maximum number of CoS v2 voice channels that may be simultaneously open within a cell. This figure in turn depends on the number of CoS v2 service invocations per A/C (indirectly on the maximum instantaneous number of A/C (n_AC) within the cell).

12.1.3. CoS v3

Voice class CoS v3 relates to a specific User Group (pilots) that is different than the User Groups associated with CoS v1. As it was assumed that this service should be available in any airspace type, one dedicated permanent channel shall be allocated per cell (n_PP=1).

NOTE: [MACONDO] limits the operational usage of CoS v3 to En-route and unmanaged airspace only. Above assumption about global availability of this service was agreed during the B-VHF high-level system design as it may increase the system flexibility.

12.1.4. CoS v4

Voice class CoS v4 uses permanent voice channels and is non-saturable. Required cell capacity does not depend on the number of A/C within the cell, but only on the number of permanent voice broadcast services per cell (n_BR). This number in turn corresponds to the number of existing broadcast channels (according to [MACONDO], the number of broadcast channels will not increase in the future due to the migration of broadcast voice services to data link).

12.1.5. CoS v5

Voice class CoS v5 will use on-demand voice channels. The required cell capacity depends on the maximum number of simultaneously open CoS v5 voice channels per cell that in turn depends on the number of CoS v5 service invocations per A/C (indirectly on the maximum instantaneous number of A/C (n_AC) within the cell.

12.1.6. CoS v-AOC

CoS v-AOC voice class will also use on-demand voice channel. This channel must be strictly separated from the voice channels used for other ATS voice service classes (CoS v1 … CoS v5), as, according to [B-VHF D5] there shall be no shared ATS and AOC voice traffic on the same functional voice channel. For this service, the cell capacity depends on the maximum number of simultaneously open CoS v-AOC voice channels per cell, that in turn depends on the number of CoS v-AOC service invocations per A/C (indirectly on the maximum instantaneous number of A/C (n_AC) within the cell).




NOTE: [MACONDO] does not address the operational usage of CoS v-AOC. During the B-VHF high-level system design it was agreed to consider this service as available in all airspace types, as this may increase the B-VHF system flexibility.

12.2. Demand for Permanent Voice Circuits

The B-VHF voice system capacity per cell will depend on the selected cell size and the scope of voice services provided by this cell, taking the required service performance into account. The cell capacity depends on parameters separately defined for different airspaces.

Airports of different size have different demands for permanent voice services. It is necessary to classify Airports and estimate specific demands of each category.

Table 12-2 gives an overview of permanent voice circuits currently used for ATC and broadcast services at representative Very Large Airport, Large Airport, small Airport and Airfield in UK. The data are based on [UK_AIP], [EUROC_VHF] and information provided by NERL in the section 4 (Reference Airspace) of this document. VHF allocations for the OPC data link (ACARS + VDL2), non-ATM channels (FIRE) and emergency voice channel have been excluded from further consideration in this section.

NOTE: Currently, 6 ATC frequencies (TWR, delivery and ground control) are in use at London Heathrow, but 7 have been assumed in Table 12-2 due to the third Heathrow runway (planned for 2015-2020).

APP channels are shown in Table 12-2, but as they are associated with TMA operations, these channels are not included into Airport permanent circuits.

It is proposed to use n_P_x parameter values from Table 12-2 as representative for any airport of a given type within the B-VHF reference area.

Service APP ATC ATIS Param. Value

Airfield – Scatsta Ness EGPM [UK_AIP], [EUROC_VHF]

1 1 n_P_AF 1

Airport (1 RWY) – Teesside EGNV [UK_AIP], [EUROC_VHF]

2 2 n_P_AT 2

Large Airport (≥2 RWY) – Manchester EGCC [UK_AIP], [EUROC_VHF]

3 5 2 n_P_LA 7

Very Large Airport – London Heathrow EGLL [UK_AIP], [EUROC_VHF], [NERL]

6 7 4 n_P_VL 11

Table 12-2: Currently Allocated Voice Circuits for Different Airport Types

In order to calculate the total number of required Airport permanent voice circuits within a range “d”, it is necessary to determine the total number of airports of each type (n_AF, n_AT, n_LA, n_VL, corresponding to Airfield, Airport, Large Airport, Very Large Airport) contained within a hypothetical B-VHF cell with a radius “d” and to apply the n_P_x values to each category.

The figures for n_AF, n_AT, n_LA, n_VL obtained from NAVSIM tool (section 5 of this document – Airborne Users’ Topology) and the total demand for voice circuits for each category – SUM (n_P_x) - are represented in Table 12-3.

Numbers for Large Airports obtained from NAVSIM have initially also contained five „Very Large Airports“. The numbers have been correspondingly reduced after „Very Large




Airports" have been introduced as a separate category. Airport communications demands for CTR zones have already been included (as TWR channels) in Table 12-3.

NOTE: It is important to consider that all ATC sectors have been taken into account, which at least partly lie within the circle with radius „d“.

Table 12-3 also indicates voice party-line demands of ATC sectors (separately for ACC/High, ACC/Low and TMA sectors). The figures have been produced for the year 2000 (data from NAVSIM), as well as for the years 2015, 2020 and 2025.

It was assumed that each ATC sector requires one dedicated permanent voice channel. It was assumed (TBC) that the number of ATC sectors will follow the same annual growth rate as foreseen for the evolution of the air traffic (3,7% per year).

The total number of required permanent voice circuits within a B-VHF cell with a radius “d” for Airports, TMA and En-route sectors can be roughly estimated by summing the contributions of different airspace types (n_P_x, n_TM, n_CT, n_AL, n_AH).

The sum represents the number of supported User Groups (n_UG) and broadcast channels (n_BR) within a cell (Table 12-1). It will depend on the decision about the cell usage (e.g. dedicated cells for En-route service, or combined cells for En-route and TMA services). One dedicated permanent channel per cell must be added to the above sum for the CoS v3 service (n_PP = 1).

It is proposed to add additional two permanent voice channels for the TMA and En-route broadcast services (VOLMET) for the cells with radius of 50 nm and above.

12.3. Demand for Temporary Voice Circuits

Temporary voice channels for CoS v1, CoS v3 and CoS v4 are allocated on-demand. It is expected that the birth- and die rates of these channels will depend on the air traffic statistics, more precisely on the number of simultaneous service users (aircraft) within a given airspace.

In order to estimate the total required number of temporary voice channels within radius “d” around the centre of the B-VHF cell, it is necessary to determine the number of aircraft within than range.

Total number of aircraft within a cell n_AC can be derived by summing up appropriate contributions according to Table 12-4 that is based on [EUROC_ADS] data for the year 2015 and has been further expanded to years 2020 and 2025 by assuming average annual air traffic growth of 3,7%.

As [EUROC_ADS] comprises neither the data about parked aircraft (that however may be active on the VHF channel), nor the detailed data for smaller Airports (except London, Brussels, Amsterdam, Paris and Frankfurt), corresponding estimated values (TBC) have been assumed in Table 12-4.

The additional number of temporary voice channels the cell must provide above permanent channel allocations will also depend on the detailed CoS v1, CoS v3 and CoS v4 service statistics within a cell.




Assumed annual traffic growth rate of active ACC sectors (2015 - 2025) ---> 3,7 %Year Description Distance „d“ (nM) from Brussels 5 12 25 50 75 100 150 200 Comment2000 [NAVSIM] Number of Airports within "d"

Very Large Airports (EHAM, LFPG, EDDF, EGLL, EBBR) [NAVSIM] n_VL 1 1 1 1 1 2 4 5Large Airports (> 1 RWY, other than very large airports) [NAVSIM] n_LA 0 0 0 1 3 6 9 17Airports (1 RWY) [NAVSIM] n_AP 0 0 0 6 12 15 30 51Airfields (no asphalt RWY) [NAVSIM] n_AF 0 0 3 11 18 24 46 70

2000 [NAVSIM] Number of full ATC sectors contained within a range "d" Permanent circuits per ACC high sector Baseline 1 n_AH 0 1 1 6 9 16 33 55Permanent circuits per ACC low sector Baseline 1 n_AL 0 3 6 20 32 53 97 160Permanent circuits per TMA zone Baseline 1 n_TM 0 4 11 32 50 67 108 135Permanent circuits per CTR zone (included at Airports) Baseline 0 N/A 0 2 5 15 27 35 56 81

2000 [NAVSIM] TOTAL Nr. of permanent Airport voice circuits within "d" Permanent circuits per Very large Airport (n_P_VL) Assumed CoS v1 11 SUM (n_P_VL) 11 11 11 11 11 22 44 55Permanent circuits per Large Airport (n_P_LA) Assumed CoS v1 7 SUM (n_P_LA) 0 0 0 7 21 42 63 119Permanent circuits per Airport (n_P_AT) Assumed CoS v1 2 SUM (n_P_AT) 0 0 0 12 24 30 60 102Permanent circuits per Airfield (n_P_AF) Assumed CoS v1 1 SUM (n_P_AF) 0 0 3 11 18 24 46 70

2000 [NAVSIM] TOTAL Nr. of permanent broadcast/air-air circuits within "d" Permanent broadcast circuits per GS Assumed CoS v4 2 n_BR 0 0 0 2 2 2 2 2Permanent air-air communications circuits per GS Assumed CoS v3 1 n_PP 1 1 1 1 1 1 1 1

2000 [NAVSIM] Number of permanent TMA/ACC voice circuits within "d" (1)Permanent circuits per ACC high sector Baseline CoS v1 1 n_AH 0 1 1 6 9 16 33 55Permanent circuits per ACC low sector Baseline CoS v1 1 n_AL 0 3 6 20 32 53 97 160Permanent circuits per TMA zone Baseline CoS v1 1 n_TM 0 4 11 32 50 67 108 135Permanent circuits per CTR zone (included at Airports) Baseline CoS v1 0 N/A 0 2 5 15 27 35 56 81

2015 [calculated] Number of permanent TMA/ACC voice circuits within "d" (1)Permanent circuits per ACC high sector Increase CoS v1 1,72 n_AH 0 2 2 10 15 28 57 95 3,7 % annual growthPermanent circuits per ACC low sector Increase CoS v1 1,72 n_AL 0 5 10 34 55 91 167 275 3,7 % annual growthPermanent circuits per TMA zone Increase CoS v1 1,72 n_TM 0 7 19 55 86 115 186 232 3,7 % annual growthPermanent circuits per CTR zone (included at Airports) Increase CoS v1 0 N/A 0 0 0 0 0 0 0 0 3,7 % annual growth



1) One permanent voice circuit has been assumed for each TMA/ACC sector contained within "d"

No significant change of permanent airport voice circuits assumed beyond 2000!

No further change in number of airports assumed beyond 2000!

Baseline figures for ACC sectors and TMA sectors!

No significant change assumed beyond 2000!

Demand for voice circuits within range "d"

Baseline figures for ACC sectors and TMA sectors!

Table 12-3: Aerodromes and CTR Statistics for Core Area




Assumed annual traffic growth rate of active ACC sectors (2015 - 2025) ---> 3,7 %

Year Description Distance „d“ (nM) from Brussels 5 12 25 50 75 100 150 2002015 [EUROC_ADS] Number of GND A/C within "d"

Nr. of moving A/C per very large airport (VL) [EUROC_ADS] 25 n_AC_VL_M 25 25 25 25 25 50 100 125Nr. of moving A/C per large airport (LA) Assumed 3 n_AC_LA_M 0 0 0 3 9 18 27 51Nr.of moving A/C per airport (AT) Assumed 0,5 n_AC_AT_M 0 0 0 3 6 7,5 15 25,5Nr. of moving A/C per airfield (AF) Assumed 0,05 n_AC_AF_M 0 0 0,15 0,55 0,9 1,2 2,3 3,5Nr. of parked active A/C per very large airport (VL) [LH] 175 n_AC_VL_P 175 175 175 175 175 350 700 875Nr. of parked active A/C per large airport (LA) Assumed 21 n_AC_LA_P 0 0 0 21 63 126 189 357Nr. of parked active A/C per airport (AT) Assumed 3,5 n_AC_AT_P 0 0 0 21 42 52,5 105 179Nr. of parked active A/C per airfield (AF) Assumed 0,35 n_AC_AF_P 0 0 1,05 3,85 6,3 8,4 16,1 24,5

2015 [EUROC_ADS] Number of flying A/C within "d" [EUROC_ADS]ACC high sectors (FL 245+) [EUROC_ADS] n_AC_AH 0 1 4 17 38 68 153 272 3,7 % annual growthACC low sectors (< FL 245) [EUROC_ADS] n_AC_AL 0 1 7 27 60 106 239 425 3,7 % annual growthTMA zones [EUROC_ADS] n_AC_TM 6 35 55 132 132 264 528 660 3,7 % annual growthTotal flying A/C [EUROC_ADS] n_AC 6 37 66 176 230 438 920 1357 3,7 % annual growth

2020 [calculated] Number of flying A/C within "d" [EUROC_ADS]ACC high sectors (FL 245+) Increase n_AC_AH 0 1 5 20 46 81 183 326 3,7 % annual growthACC low sectors (< FL 245) Increase n_AC_AL 0 1 8 31 72 127 286 510 3,7 % annual growthTMA zones Increase n_AC_TM 7 42 66 158 158 316 632 790 3,7 % annual growthTotal flying A/C Increase n_AC 7 44 79 209 276 524 1101 1626 3,7 % annual growth

2025 [calculated] Number of flying A/C within "d" [EUROC_ADS]ACC high sectors (FL 245+) Increase n_AC_AH 0 1 6 24 55 98 220 391 3,7 % annual growthACC low sectors (< FL 245) Increase n_AC_AL 0 2 10 38 86 153 344 611 3,7 % annual growthTMA zones Increase n_AC_TM 10 51 79 190 190 380 760 950 3,7 % annual growthTotal flying A/C Increase n_AC 10 54 95 252 331 631 1324 1952 3,7 % annual growth

No further significant increase of airport capacity (number of A/C) assumed beyond 2015!

Table 12-4: Aircraft Statistics for Core Area




12.4. Estimation of Voice Protocol Overhead

The protocol overhead above (vocoder-) voice payload will be estimated within the B-VHF WP3, including signalling, support for automated functions e.t.a.).

12.5. Representative Voice Exchanges

For the purpose of B-VHF system capacity simulation it is necessary to define a “per-flight” voice profile that is representative for a given airspace type. This voice pattern will typically comprise multiple voice services and will be triggered during the B-VHF performance simulation exercises at the moment of aircraft entry into simulated airspace. Once triggered, the pattern will be executed for the duration of the flight in a given airspace.

The construction of voice patterns for all voice service classes is described in the section 11 (Scenarios of Future Voice Service Development) of this document. In this chapter the “standard building blocks” of voice patterns – called representative voice exchanges - are proposed.

[MACONDO] and [B-VHF D5] have used voice statistics for a single ATC voice exchange (= voice contact in [MACONDO] terminology) as shown in Table 12-5. This statistics has been derived from the En-route voice statistics [VOCALISE_1], [VOCALISE_2], but has been used for scenarios of voice usage in all airspace types (En-route, TMA and Airport). In order to be able to validate the results of B-VHF performance and capacity simulation against [B-VHF D5] requirements, the same statistics should be used when preparing detailed simulation scenarios (WP 3 of the B-VHF project).

Nr. of A/C per sector (assumed) 20

Mean channel loading (%) 30

Estimated 95% bound (%) for mean channel loading (used for voice capacity calculations) 60

Average number of verbal acts (VA) per exchange 2,8

Average duration of single verbal act (VA) (s) 3,3

Average duration of a pause (P) after a verbal act (s) 1,2

Calculated average duration of voice exchange (VE) (s) 11,4

Controller’s percentage of all verbal acts (%)12 45

All pilots’ percentage of all verbal acts (%) 55

Table 12-5: ATC Voice Statistic Parameters

The above statistics allows for the creation of a "Standard Voice Exchange" (SVE), "Standard Voice Profile" (SVP) and “Standard Broadcast Profile” (SBP) to be used in B-VHF scenarios. In all cases average VA values and pause values are used, resulting in average voice exchange duration.

12 This statistics should be used when deciding whether the first verbal act of a "standard exchange" was on UL or DL.




12.5.1. Standard Voice Exchange

"Standard Voice Exchange" (SVE) shown in Figure 12-1 comprises one VA-P-VA block (average duration of entire block, including two pauses: 7,8 s), in 80% of all cases immediately followed by an additional P-VA block (average duration of additional block, including one VA and a pause: 4,5 s).

Each VA is defined with the corresponding PTT event. The direction of the first VA block also determines the direction of the (optional-) VA block (the VAs are alternating). It should be selected in such a way that the total number of forward/reverse link VA blocks over the entire profile satisfies the global distribution between controller and the pilots (45%/55%).

Figure 12-1: Standard Voice Exchange

12.5.2. Standard On-demand Exchange

"Standard On-demand Exchange" (SOE) shown in Figure 12-2 comprises one VA-P-VA block (average duration of entire block, including two pauses: 7,8 s), in 80% of all cases immediately followed by an additional P-VA block (average duration of additional block, including one VA and a pause: 4,5 s).

Opposite to SVE, there are additional signalling transactions at the beginning/end of each block in order to establish/release on-demand voice circuits. Between such signalling transactions, each VA within a block is associated with one PTT event.

The direction of the first VA block also determines the direction of the (optional-) VA block (the VAs are alternating). It should be selected in such a way that the total number of forward/reverse link VA blocks over the entire profile satisfies the global distribution between controller and the pilots (45%/55%).

Figure 12-2: Standard On-demand Exchange

VA VA P P

VA

VA VA P P

VA

SIG

SIG

SIG

SIG

SIG

SIG

SIG

SIG

VA VA P P

VA

VA VA P P

VA




The total allowed duration of a signalling transaction (including one forward and one reverse link exchange) is defined by the value of the [B-VHF D5] Table 4-5/ “Max. Connection Establishment Time” parameter. This value should be monitored during the B-VHF performance simulation.

12.5.3. Standard Broadcast Transmission

"Standard Broadcast Transmission" (SBT) applies only to the Ground Station (GS). It is characterized by a continuous broadcast forward link transmissions (GS is the sole user of a dedicated communication channel, the GS transmitter is keyed all the time, the channel duty-cycle is 100%).

12.6. Voice Service Evolution

[MACONDO] provides estimates about time evolution of per-aircraft voice traffic separately for each service class up to the year 2015. The total voice traffic will be generated by merging per-aircraft voice profiles across the whole aircraft population applicable to a given airspace. Sub-set of these data (for 2015) was captured in [B-VHF D5] (Table 4-5).

Table 12-7 shows these data supplemented by the CoS v4 (broadcast service) that was originally not included in [MACONDO], data. This service requires one full dedicated channel and an aircraft is not actively involved with broadcast communications. Also, estimates have been added about CoS v-AOC service that was outside scope of [MACONDO].

Table 12-7 comprises selected parameters from [B-VHF D5] (shaded area relates to original [MACONDO] data up to the year 2015):

Service Identifier (CoS)

Applicability area (Airport - AP, TMA, En-route -ENR)

Maximum connection establishment time in seconds (T_e)

Reduction factor (R) with respect to the Reference value (2000)

Number of voice contacts per A/C per hour (N_c)

Average cumulative contact duration per hour in seconds (T_c)

95% capacity per aircraft in mE (C_v)

Additionally, the type of voice transaction (SVE, SOE, SBT) has been indicated.

T_c was calculated by using fixed average duration of a single contact (11s).

The figures provided in Table 12-7 already include impact of data link onto voice services. Similarly, the reduction factor “R” already includes distribution of service classes onto different airspace types (applicability area).

The value of R = 0,9 for the CoS v1-1 service (in TMA) by 2010 means that party-line service will be used for 90% of TMA tactical voice exchanges by that time. [MACONDO] assumed further 10% CoS v1-1 reduction by 2015, due to the completed porting of inter-sector communications handoff (non-critical routine task) to the data link.

The value of R = 0,55 for the CoS v1-2 service by 2010 means that at that time 50% of initial airport (AP) and en-route (ENR) voice party-line traffic has been ported to data link (only 50% of initial reference voice traffic remains provided as a party-line service), but




the backup of data link requires additional 5% capacity (50% + 5% = 55%). By 2015, almost all AP and ENR voice traffic is expected to be ported to data link, so the CoS v1-2 service will be used in only 6% of all cases (R = 0,06), mainly as a backup for data link.

NOTE: In spite of the overall reduction of voice traffic due to the migration towards data link, the voice circuits for “permanent” voice services (CoS v1, CoS v3, CoS v4) will have to remain permanently allocated (available) by 2015 and beyond, even if these services may be only occasionally used.

Assumed 5% (R = 0,05) for CoS v2 means that by 2010 selective voice service will be used in 5% cases as a backup for data link.

The rest of Table 12-7 (years 2020 and 2025, respectively) has been constructed based on assumed further reduction of the volume of ATS voice service beyond the year 2015. As no reliable data are available for that time frame, some assumptions had to be made (TBC):

a) By 2020 in-flight ATM data link services (CoS D-4) will become available on a broad basis, reducing the need for tactical voice exchanges and leading to the further reduction (20%, ref. to 2015) of usage of CoS v1-1 service (within TMAs)

b) After 2020, there will be no further reduction of CoS v1-1 usage (as the relieving potential of the CoS D-4 class was exhausted)

c) After 2015 there will be no significant change with respect to the CoS v1-2 and CoS v3 usage, respectively

d) By 2020, there will be slight increase (R = 0,15) of CoS v2 service usage when compared with 2015 (due to the possible further reduction of usage of the party-line service in En-route airspace after 2015).

e) After 2020, the CoS v2 service will not significantly change anymore.

f) By 2020, there will be slight increase (R = 0,1) of CoS v5 service usage when compared with 2015 (due to the introduction of new operational concepts involving other-than-controller ground operational staff that may require this service type).

g) Further increase (R = 0,15) of CoS v5 service usage may be expected by 2025.

Table 12-6 shows the number of OPC voice circuits currently used at representative airports in UK. It is based on [EUROC_VHF] and NERL data provided in the section 4 (Reference Airspace) of this document and does not cover AOC data link channels. The parameter n_OP_A from Table 12-6 may be used as an estimate for the peak demand for on- demand AOC voice channels (to be provided in the future as CoS v-AOC service).

Service OPC n_OP_A

Very Large Airport – London Heathrow - EGLL - [NERL] Voice 25

Large Airport (≥2 RWY) – Manchester - EGGC – [EUROC_VHF] Voice 11

Airport (1 RWY) – Teesside EGNV - [EUROC_VHF] Voice 1

Airfield – Scatsta Ness EGPM - [EUROC_VHF] Voice 0

Table 12-6: Currently Allocated Voice Circuits for Different Airport Types

It can be seen that in London Heathrow 25 OPC channels and 6 ATC channels are currently in use. This means that OPC voice communications at large airports today require a relatively large capacity (large number of allocated VHF channels).




For the purposes of the B-VHF project, some baseline OPC voice profile parameters (as applicable to the year 2000) have been proposed by a large European airline:

a) Number of OPC voice contacts per aircraft per hour N_c = 0,5

b) Maximum duty-cycle on an OPC voice channel D_c = 60%

c) Maximum range of OPC voice communications d_OPC = 350 nm

d) Average duration of an OPC voice contact t_OPC = 20 s

NOTE: VHF OPC communications are typically concentrated on first and last hour of flight at departure and destination airports. For short range flights with an average flight time of 1 hour, there are about 0,5 OPC voice contacts per A/C per hour, with average contact duration of 20 s. Clearly, these values may vary, dependent on the airline, flight duration and other parameters. The loading of OPC voice channels that may be allocated to the particular airline may be very different, but the maximum duty-cycle of any channel does not exceed 60%.

Decrease rate of OPC voice service usage

It was assumed that the demand for CoS v-AOC service will remain unchanged (100% of 2000 baseline) until 2010. From 2010 on, the demand will decrease with a rate of 30% per 5 years. By 2025 there would still be demand for CoS v-AOC service (about 10% of the 2000 baseline), as not all AOC voice communications can be replaced by the AOC data link.

Table 12-4 parameters shall be used when developing detailed scenarios for the B-VHF voice capacity and performance simulation for the year 2015, 2020 and 2025, respectively.

12.7. Scenarios for the Year 2015, 2020 and 2025

The scenarios for the simulation of B-VHF voice services by 2015, 2020 and 2025, respectively, shall be based on the data provided in Table 12-7. Representative voice applications and detailed scenarios of their usage are yet TBD within the WP 3 of the B-VHF project.

It shall be possible to activate - independently for each aircraft - one or several (all-) voice service classes (CoS v1 … CoS v-AOC) during simulation. The decision about which services apply to which A/C depends on the level of B-VHF equipage and the B-VHF system deployment scenario (voluntary- vs. mandated carriage of B-VHF equipment). Moreover, the service applicability may vary between different airspace types.

Different service classes will have different specific profiles, as shown in Figure 12-3. For the CoS v3 service, both options (party-line and PP on-demand provision) have been shown.




Average duration of single ATC voice contact [MACONDO] (s): 11Average duration of single OPC voice contact [LH] (s): 20Average number of OPC voice contacts per flight per hour [LH]: 0,5Year Service Reduction Coefficient (% of

Reference)Nr. of contacts per

A/C per hrContact duration per A/C per hr (s)

Capacity per A/C (95%) (mE)

Type of voice transaction

R N_c T_c C_vAP TMA ENR AP TMA ENR

Reference =1 9,8 108 30 SVEReference =1 0,5 10 2,78 SOEReference =1 N/A 3600 1000 SBT

CoS v1-1 X 1 0,9 8,82 97,02 26,95 SVECoS v1-2 X X 10 10 0,55 5,39 59,29 16,47 SVECoS v2 ? X 20 20 0,05 0,49 5,39 1,5 SOECoS v3 ? ? X 1 1 1 0,02 0,2 2,2 0,61 SVECoS v4 X X X N/A N/A N/A 1 N/A 3600 1000 SBTCoS v5 X X 20 20 0,02 0,2 2,2 0,61 SOECoS v-AOC X X X 20 20 20 1 0,5 10 2,78 SOECoS v1-1 X 1 0,8 7,84 86,24 23,96 SVECoS v1-2 X X 10 10 0,06 0,59 6,49 1,8 SVECoS v2 ? X 20 20 0,05 0,49 5,39 1,5 SOECoS v3 ? ? X 1 1 1 0,02 0,2 2,2 0,61 SVECoS v4 X X X N/A N/A N/A 1 N/A 3600 1000 SBTCoS v5 X X 20 20 0,02 0,2 2,2 0,61 SOECoS v-AOC X X X 20 20 20 0,7 0,35 7 1,94 SOECoS v1-1 X 1 0,6 5,88 64,68 17,97 SVECoS v1-2 X X 10 10 0,06 0,59 6,49 1,8 SVECoS v2 ? X 20 20 0,15 1,47 16,17 4,49 SOECoS v3 ? ? X 1 1 1 0,02 0,2 2,2 0,61 SVECoS v4 X X X N/A N/A N/A 1 N/A 3600 1000 SBTCoS v5 X X 20 20 0,1 0,98 10,78 2,99 SOECoS v-AOC X X X 20 20 20 0,4 0,2 4 1,11 SOECoS v1-1 X 1 0,6 5,88 64,68 17,97 SVECoS v1-2 X X 10 10 0,06 0,59 6,49 1,8 SVECoS v2 ? X 20 20 0,15 1,47 16,17 4,49 SOECoS v3 ? ? X 1 1 1 0,02 0,2 2,2 0,61 SVECoS v4 X X X N/A N/A N/A 1 N/A 3600 1000 SBTCoS v5 X X 20 20 0,15 1,47 16,17 4,49 SOECoS v-AOC X X X 20 20 20 0,1 0,05 1 0,28 SOE

Shaded areas refer to data obtained from [MACONDO]

Service Application Area Maximum Connection Establishment Time (s)

T_e

2000 All ATM functionsOPC voiceBroadcast

2010

2015

2020

2025

Table 12-7: Voice Service Evolution




The CoS v1 service will by 2015 (Figure 12-3) require two mandatory transactions related to the handoff between sectors. One "Standard Voice Exchange" (SVE) should be triggered at the beginning of the contact on the channel associated with the given User Group (for ATC sectors: triggered immediately over the sector boundary), another SVE should be executed prior to leaving the User Group’s party-line channel. Between these transactions, an appropriate number of “intermediate” SVEs should be executed, according to the parameter N_c of Table 12-7.

It should be checked separately for each party-line service, whether the sum of all per-aircraft CoS v1 voice profiles from Table 12-7 for the total applicable aircraft population produces still acceptable voice channel duty-cycle (below 60%).

Later on, the leading/closing transactions may be omitted (as the information about the next sector frequency/channel will be provided via data link). Resulting pattern within a sector would start with a variable pause and end with another pause. The impact of performing sector handoff via data link (reduced number of CoS v1 voice transactions) has already been included in Table 12-7.

The dwell time of an A/C within an ATC sector shall be derived from the dwell time statistics obtained from the NAVSIM tool as specified in the section 5 of this document (Airborne Users’ Topology).

Figure 12-3 shows time gaps required for the handoff between ATC sectors (“H”), as well as between B-VHF cells (“C”). Times required for the setup (“S”) and release (“R”) of on-demand voice services (CoS v2, CoS v3 provided in the PP mode, CoS v5, CoS v-AOC) are indicated as well. These times should be checked against required maximum allowed connection establishment time (T_e) as specified in Table 12-7. It should be possible to select a new CoS v1 service channel within 1 second. The parameter T_e for on-demand services CoS v2, CoS v5 and CoS v-AOC is less demanding (20 s).

When the pilot selects the CoS v3 service in the party-line mode, the service should be available – similar to the selection of a new sector’s channel – within the service establishment time T_e for the CoS v3 service (1 s).

It should be decided in the WP 3 prior to the simulation, whether an A/C may simultaneously participate in more than one voice session (use more than one voice service at any time).




Figure 12-3: Sample Voice Scenario (AP, TMA, ENR)

----------- END OF SECTION -----------

Pause Pause Pause

CoS v-AOC

Pause Pause Pause CoS v-1

CoS v-2

CoS v-4

CoS v-5

Pause Pause

SBT

Pause

Pause

H H H Pause C Pause

H

SVE SVE SVE SVE SVE SVE

SVE S R

SOE

SVE S R

C

C

C

SBT

C

H Pause

SOE

SVE S R

SOE

SVE S R Pause

SOE

SVE S R

SOE

SVE S R

Pause

Pause Pause

Sector Sector Sector

B-VHF Cell B-VHF Cell

Cell Handoff Sector Sector

SVE

Pause HCoS v-3




13. Non-technical Aspects Affecting the B-VHF System

This chapter describes some non-technical aspects related to existing VHF voice and data communications systems that may be relevant to the deployment of new terrestrial mobile systems like B-VHF.

As these aspects are not related to the functionality or performance of the future communications system, no specific requirements have been captured in [B-VHF D5]. Still they may have relevance for the overall system acceptance, therefore they should be taken into account during the B-VHF system.

13.1. Single European Sky

Achieving a Single European Sky is a clear objective of the European Commission. A key enabler for a seamless European ATM network is the provision of cross-border air navigation services.

At present 26 FIRs and 19 UIRs (Upper Flight Information Regions) exist in the airspace under the responsibility of the Member States of the European Community. One of future tasks [EATMP_COM_S] is to restructure European airspace as a function of air traffic flow, rather than – as today - according to national borders.

The Single European Sky programme aims to establish a single "European Upper Flight Information Region" (EUIR). The EUIR [ICAO_ANC11_1] will encompass the upper airspace falling under the responsibility of the Member States and as appropriate may also include adjacent airspace of countries that are non-members of the European Community. Upper airspace shall be reconfigured into functional airspace blocks that are optimised to reflect operational requirements regardless of national boundaries.

The supplementary concept of Flexible Use of Airspace (FUA) will allow the efficient allocation and use of military airspace and the timely opening of such airspace to civil flights. The integrity of military operations will be safeguarded by protection mechanisms - member States will have the possibility of temporarily suspending the application of the FUA concept in case of significant operational difficulties.

States will retain their power to designate providers of air traffic services and meteorological services operating under monopoly conditions within a specific airspace. However, service providers and airspace users will have a choice of aeronautical services and CNS services.

B-VHF system will have to support these trends (e.g. dynamic re-sectorisation) under both national- and cross-border scenarios by providing flexible physical coverage (cellular concept) accompanied by the easy system re-configuration and management.

13.2. Institutional Issues

In the context of aeronautical communications, institutional issues (related to ownership, control and responsibility for correct implementation and operation of systems which involve more than one state or organisation, ICAO definition) present a potential risk to the realisation of those communication projects involving a number of states.

New trends [EATMP_COM_S] in the business environment in which the communications services are provided include delegation of some national ATS responsibilities on a co-operative basis to neighbouring states or regional ATS providers, as well as increasing




general acceptance of telecommunications service providers for both administrative and ATS-related traffic. Outsourcing of services is already prevalent in some States. SITA and ARINC are well-established global service providers specialising in providing mobile communications services to the aeronautical community. Other market entrants may also appear in the future.

Future European aeronautical communications services will become a “federated responsibility”. Separation between regulatory and operational functions shall be ensured at the European level. Service level requirements will be set through international initiatives, service provision itself will be addressed nationally and regionally, based on economic and political factors.

Future ATM system may be constructed from autonomous components that are independently developed, owned and maintained. Global implementation of a seamless ATM system through the provision of CNS/ATM facilities and seamless services shall neither infringe nor impose restrictions upon States’ sovereignty, authority, or responsibility in the control of air navigation and the promulgation and enforcement of safety regulations [ICAO ATM OC].

New communications technologies like B-VHF should be built in such a way to allow for distributed management of the communication network – including span of control, ownership and costs – in order to meet the institutional requirements of national autonomy. Dependent on the particular situation, a trade-off may be required between non-technical institutional aspects and the achievable technical system efficiency (e.g. system capacity may have to remain below the theoretically achievable level due to the specific ownership constraints).

13.3. Shared Broadband Technology

Normally, European States are responsible for organization and provision of ATC services to users within their national boundaries. There are some exceptions where service provision has been delegated to another State or regional service provider(s). The full list of potential ATM service providers comprises [ICAO ATM OC] State agencies, State-owned-, privatized and regional ATM service providers, as well as independent private sector ATM service providers of ground- and space-based CNS/ATM services.

According to today’s practices, each ATM provider may use its own A/G communications infrastructure that is deployed and managed independently of the infrastructure owned by other providers.

More specifically, each (ATS) facility within a given ATM provider domain may use its own infrastructure. In some cases facilities can be combined together (e.g. co-located En-route and Approach control), but the communication infrastructure they use when providing En-route and TMA services may still be separated from each other.

Service independency is today maintained down to the ground radio station level. Theoretically, each narrowband VHF service may deploy its own ground infrastructure (GSs). Any appropriate location may be selected for a physical GS as long as it can provide required operational coverage for a given service. For practical reasons several services may be provided from the same physical location, but the required radio infrastructure can be considered as several “independent” GSs.

B-VHF broadband communications systems is based on CDMA and can offer maximum spectral efficiency and communications capacity only if multiple services are provided from the same physical location (GS). Moreover, spectrum availability constraints




combined with efficient provision of communications services may within a broadband system like B-VHF lead to the requirement for currently independent ATC- and other facilities (ACC/UAC) to share both the broadband radio channel and underlying technical systems (Ground Stations, including broadband transmitters and receivers). Additionally, the separation of responsibilities for the provision of voice and data link services and the management of corresponding physical infrastructure (including system ownership and management issues) becomes more complicated.

An acceptable trade-off between system efficiency and user operational independency is yet TBD, but specific provisions – including transparent resource management, possibility to virtually separate communications resources used by different facilities - must be considered during a B-VHF system design.

13.4. Preserving Investments

Planning, deployment and maintenance of the ground ATM communications infrastructure is associated with many interleaved non-trivial issues. This includes-, but is not restricted to selection of site locations that can provide desired physical coverage, resolving property issues, deployment of buildings and antenna towers, installing antennas, power supplies, wired- and wireless systems interconnecting the GS with other remote ground voice/data systems. Clearly, the cost of the radio communications equipment is only a relatively small part of the total infrastructure costs.

ATSPs aim to preserve as much as possible of their past investments when replacing the radio technology. They would prefer to continue to use existing GSs with existing facilities like antennas with a new system.

The situation can be even more restrictive when looking at the infrastructure at the airborne side. New on-board technologies should be preferably deployed in a “plug-and-play” manner, by replacing or upgrading only the necessary minimum of airborne items. Alone a requirement to add additional antenna(s) or modify existing aircraft cabling may significantly reduce- or postpone the acceptance of the new communications technology.

An implicit requirement to integrate and re-use existing infrastructure and existing components wherever possible also applies to the high-level B-VHF system design.

However, it must also be recognized that new technologies like B-VHF have their specific detailed requirements that must be fulfilled if the technology is to provide maximum benefits to the users and that further technology-independent changes (e.g. new system interfaces, new HMIs) will anyway be required solely due to the evolution of the operational communications services.

The B-VHF technology has therefore to be designed in such a way that only very limited changes are required at the airborne side during initial deployment (the VDL Mode 3 introduction strategy has shown that the ground ATM system may tolerate more changes than the airborne side). At the same time, the system design should remain flexible and upgradeable, open to possible architecture changes over an extended period of time. This would allow to combine operational services and the underlying technology and release them as “service packages” with gradually increased overall performance and capabilities.




13.5. Information Management

With an overlay B-VHF deployment concept, B-VHF RF channels and detailed MC-CDMA and OFDMA resources are dynamically allocated. Different RF channels will be allocated to different B-VHF cells. The detailed constellation of available OFDM carriers will be different within each B-VHF cell (and possibly within each ATC sector). Moreover, this constellation will probably differ between the B-VHF Forward Link (FL) and Reverse Link (RL).

ATSPs wanting to deploy the B-VHF System would need to perform - as a part of the safety assessment - a detailed analysis of the VHF occupancy and interference situation within the whole airspace they are responsible for. As an outcome, detailed information required for configuring each particular B-VHF Ground Station Controller (GSC). The GSC will in turn use this information to configure B-VHF systems of entering A/C during the net entry procedure.

Such an analysis will require detailed knowledge about global current usage of VHF frequency resources over entire region. Centralized regional- or even global data base may be the best way to provide frequency usage data with integrity and consistency required for subsequent rigorous safety analysis. EUROCONTROL Communications Strategy [EATMP_COM_S] has recognized that the quality of currently available data bases with frequency information is not satisfactory and has stated, that “ICAO, EUROCONTROL and States must critically review and improve the quality-, as well as the management of a central and reliable Frequency database as a prerequisite for concrete improvements of Frequency Management”. Any further step into this direction would enforce the B-VHF overlay deployment concept.

Dependent on the adopted detailed B-VHF mechanisms, some AIP information will have to be updated to allow for the pilot’s proper selection of B-VHF services, but the intention of the B-VHF project is to keep the degree of such updates at an absolute minimum.

13.6. Security

In the broader ATM context, security [ICAO ATM OC] refers to the protection against threats which stem from intentional (e.g. terrorism) or unintentional (e.g. human error, natural disaster) acts affecting aircraft, people or installations on the ground. The ATM system itself, as well as ATM related information, should be protected against security threats.

There is an ongoing work within the aeronautical community with respect to the security aspects of voice and data aeronautical communications. ATN security provisions have already been covered by the CNS/ATM package 2.

[ICAO_ANC11_3] gives an overview of some security requirements for mobile communications:

Avoidance of unauthorized view: air-to-ground communications can be easily monitored using commercially available receivers. This issue should be dealt e.g. by means of message encryption and authentication of the information source;

Capability to operate in presence of interference (jamming): air-to-ground communications can be easily jammed using a commercial transmitter. This could be avoided e.g. by means of frequency hopping or spread spectrum transmissions;

Capability to operate in presence of masquerading (spoofing): air-to-ground communications can be easily deceived (or “spoofed”) using a commercial




transmitter. This could be avoided by message authentication; frequency hopping or usage of spread spectrum;

Data integrity: an alternative air-to-ground communication link (as example a SATCOM link) could be the means to assure the integrity level for critical and sensible information;

Physical separation: ATM air-to-ground communications should be possibly separated from other air-to-ground services.

Future B-VHF communications system must be designed according to these principles. In particular the requirements affecting the technology itself (b, e, partially c) should be adequately considered during the system design. While recognized the importance of other security requirements, it has to be pointed out that end-to-end security concepts like message- or user authentication (a, partially c) and the concept of technological diversity (d) are beyond the scope of the ongoing B-VHF project.

13.7. Safety Aspects of Integrated Voice-Data Systems

New communications services can only be introduced taking into account the appropriate safety regulatory baseline, and applying appropriate safety assessment methodologies or guidelines in order to identify and mitigate all safety risks [EATMP_COM_S].

Due to the narrowband nature of service provision, the provision of voice and data link VHF communications services – including the necessary ground infrastructure - can today be organized to be independent from each other.

In the most cases the infrastructure for provision of voice services is deployed and managed directly by the national ATSP. The infrastructure required for data link is completely separated from those required for voice services and delegated to independent communications service providers (SITA, ARINC).

NOTE: Some European ATSPs consider the option to deploy and manage their own data link infrastructure.

[EATMP_COM_S] states, that the safety cases of voice and data over the same link will require to be studied with particular reference to failure modes and consequences and that further benefits may exist in the possibility to combine new technology for communications, navigation and surveillance purposes.

New B-VHF technology is capable of providing integrated voice and data over the same communication channel. Moreover, it is capable to combine different kinds of (e.g. communications and surveillance-) data links. Safety requirements for voice and data communications services covered by the B-VHF system [B-VHF D5] have been derived - at a level of generic communications service classes - from [MACONDO]. It is expected that prior to any operational deployment the capability of the B-VHF technology to support a particular ATM service (or a mixture of services) will be subject to further careful validation.

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14. Conclusions

The B-VHF project develops and validates basic functional principles and architecture of completely new VHF communications sub network technology, capable to support both current aeronautical communications needs and estimated future demands.

The deliverable D5 of the WP 1 of the B-VHF project - Report on Applications Communications Requirements - defines high-level functional and performance requirements for the B-VHF communications technology, derived from a set of selected reference documents. Being a requirements document, D5 just specifies necessary functional and performance aspects of a new system, but does not describe in detail the operational environment in which such a system should be used.

WP 1 deliverable D8 - B-VHF Reference Environment document - supports the task of B-VHF system design. It “sets up the scene” for the B-VHF system deployment by providing supplementary information not being covered by the deliverable D5. Additionally, it provides information necessary for the tasks of B-VHF interference modelling, development of B-VHF Operational Concept and subsequent system performance evaluation within the WP 3 of the B-VHF project.

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15. References

Nr. Reference ID Reference

1 [AMCP8-WP51] AMCP eighth meeting, Montreal, 4-13 Feb. 2003/ WP/51, VDL Frequency Assignment Planning Criteria

2 [SPG/CP0108] DIS/COM/SPG/CP0108 – Radio Characteristics of Aviation Radio Systems, Step 1, Ver. 2.0, 07.08.2000

3 [AMCP8-WP44] AMCP eighth meeting, Montreal, 4-13 Feb. 2003/ WP/44, PROGRESS OF THE VDL SUB BAND IMPLEMENTATION IN EUROPE

4 [GET MET] GET MET 2004, Brochure of UK CAA Met Office, http://www.meto.gov.uk/aviation/services/getmet.pdf

5 [CEPT ARC] CEPT/ERC- THE EUROPEAN TABLE OF FREQUENCY ALLOCATIONS AND UTILISATIONS COVERING THE FREQUENCY RANGE 9 kHz TO 275 GHz, Lisboa January 2002 Revised Dublin 2003

6 [EUR_FM_man] ICAO EUROPEAN AND NORTH ATLANTIC OFFICE – EUR FREQUENCY MANAGEMENT MANUAL for Aeronautical Mobile and Aeronautical Radio Navigation Services, EUR Doc 011, Edition 2003, September 2003 (unofficial version)

7 [RTCA-DO224A] RTCA/DO224A- MASPs for Advanced VHF Digital Data Communications Including Compatibility With Digital Voice Techniques, Sept. 13, 2000.

8 [ETSI_VDL4] ETSI EN 301 842-1 V1.1.1 (2001-11), Electromagnetic compatibility and Radio spectrum Matters (ERM); VHF air-ground Data Link (VDL) Mode 4 radio equipment; Technical characteristics and methods of measurement for ground-based equipment; Part 1: General description and physical layer

9 [ARINC_618] AIR/GROUND CHARACTER-ORIENTED PROTOCOL SPECIFICATION ARINC SPECIFICATION 618-5, PUBLISHED: AUGUST 31, 2000

10 [VOCALISE_1] CENA /NT02-032/ Main lessons learnt from the VOCALISE 2000 study, VOCALISE/Phase 1, 17/04/02

11 [VOCALISE_2] Etude Vocalise : Analyse générale Trafic CRNA / France 2000, Une analyse du canal vocal pilotes contrôleurs dans la perspective d’un environnement data-link, CENA/ICS/R02-002, version 1.0, 07/03/02

12 [DO-186A] RTCA/DO-186A, Minimum Operational Performance Standards for Airborne Radio Communications Equipment Operating Within The Radio Frequency Range 117,975 – 137,000 MHz, October 20, 1995

13 [WGB16/WP19 AERONAUTICAL COMMUNICATIONS PANEL (ACP) Working Group B, Tokyo, 28th January to 6 February 2004, ACP/WG-B/WP_19, Assessment of VDL Mode-2 airborne co-site interference in Link2000+ framework

14 [DFS_VDL4] Report on test procedures and measurement results for the development of frequency planning criteria for VDL Mode 4, Author: Dr. Armin Schlereth, DFS, Date: 5th September 2001

15 [SITA AEEC] SITA AEEC DL Users Forum Presentations, San Francisco, California February 4-5, 2004

16 [ARINC AEEC] ARINC AEEC DL Users Forum Presentations, San Francisco, California February 4-5, 2004




17 [ETSI VDL2] ETSI EN 301 841-1 V1.1.1 (2002-01), European Standard (Telecommunications series) Electromagnetic compatibility and Radio spectrum Matters (ERM); VHF air-ground Digital Link (VDL) Mode 2; Technical characteristics and methods of measurement for ground-based equipment; Part 1: Physical layer

18 [ARINC EUR GLOBALINK]

http://www.arinc.com/products/voice_data_comm/air_ground_radio_svc/jeppesen_charts/ARINC-9 GLOBALink VHF Europe ACARS Coverage.pdf

19 [ICAO 9705] Manual of Technical Provisions for the ATN (ATN SARPS), Ed. 3

20 [ICAO 9739] Comprehensive Aeronautical Telecommunication Network (ATN) Manual, Ed. 2

21 [F-VHF] EATCHIP- Future VHF Systems –Architecture Identification, Initial Situation, WP 2210, http://www.eurocontrol.int/fvh/fDeliverables/WP2000/wp2210.zip

22 [VM4AAS-D1] VDL Mode 4 Airborne Architecture Study (VM4AAS) Deliverable D1: Definitions, Assumptions and Baselines, V1.0, 20. October 2003

23 [VM4AAS-D5] VDL Mode 4 Airborne Architecture Study (VM4AAS) Deliverable D5: Overall Study Summary and Final Report, V3.0, 10. December 2003

24 [ACP WGB16/WP12]

ACP WGB16/WP12 – Co-site radio interference between DSB-AM and VDL Mode 3, AERONAUTICAL COMMUNICATIONS PANEL (ACP) WG-B 16th MEETING, Tokyo, 28th January-6th February 2004

25 [MACONDO] EATM- Operating Concept of the Mobile Aviation Communication Infrastructure Supporting ATM beyond 2015, WP2 - OC, Ed. 1.0, July 2002

26 [NERL_GS] Data base of En-route and TMA ground stations in UK, NERL, Frequencies and Radio Stations.mdb, 20.04.2004

27 [EUROC_VHF] EUROCONTROL Data base of European VHF frequency allocations, BP17_COM2DB.mdb

28 [LH_DL] LH data link profile, presentation PROFILNEU.ppt, 12.07.2003

29 [B-VHF D5] B-VHF D-05 – Report on Applications Communications Requirements, Issue 1.0, 15.06.2004

30 [UK_AIP] http://www.ais.org.uk

31 [DL_ROADMAP] Roadmap for the implementation of data link services in European Air Traffic Management (ATM): Technology Assessment, Date: 28 February 2003

32 [ODIAC] EATMP/AGC-ORD-01/Operational Requirements for A/G Cooperative Air Traffic Services, Ed. 1.0, 2 Apr. 2001.

33 [CLIMAX_TECH] EATMP/ Feasibility and benefit analysis of CLIMAX operations on a VHF 8.33 kHz channelisation, WP 2 – Technical feasibility, Deliverables D2.a and D2.b , Ed. 1.0

34 [CLIMAX_SPECT] EATMP/ Feasibility and benefit analysis of CLIMAX operations on a VHF 8.33 kHz channelisation, WP 1 – Spectrum Benefit, Deliverable D1.a, Ed. 1.0, 14. May 2004

35 [VDL2_AIR] EUROCAE/ MINIMUM OPERATIONAL PERFORMANCE SPECIFICATION FOR AN AIRBORNE VDL MODE-2 SYSTEM OPERATING IN THE FREQUENCY RANGE 118-136.975 MHz, ED-92A, October 2002

http://www.ais.org.uk/




36 [VDL4_AIR] EUROCAE/ INTERIM MINIMUM OPERATIONAL PERFORMANCE SPECIFICATION FOR VDL MODE 4 AIRCRAFT TRANSCEIVER, PART 1: CORE REQUIREMENTS, DRAFT version GH, 23rd January 2004, ED-108A

37 [EUROCONT_1] E-mail, 28.07.2004 (Antonio Astorino), with explanation of service names used in [EUROC_VHF]

38 [EUROC_ADS] Eurocontrol ADS Programme – High-Density 2015 European Traffic Distributions for Simulation, Ed. 1.2, 24.03.2000

39 [B-VHF_IR-11] B-VHF IR-11, Internal Report on Current VHF Environment and Practices, Issue 1.0, 26.07.2004

40 [ICAO_ATM_OC] ICAO 11th Air Navigation Conference, WP/4 APPENDIX ATM OPERATIONAL CONCEPT DOCUMENT

41 [EATMP_COM_S] EATMP COMMUNICATIONS STRATEGY - VOLUME 2 – TECHNICAL DESCRIPTION, Ed. 5.0, 25 August 2003

42 [ICAO_ANC11_1] ICAO Eleventh Air Navigation Conference, Action paper: ESTABLISHMENT OF THE EUROPEAN UPPER FLIGHT INFORMATION REGION (EUIR) IN THE COURSE OF THE IMPLEMENTATION OF THE SINGLE EUROPEAN SKY

43 [ICAO_ANC11_2] ICAO Eleventh Air Navigation Conference, Information paper: A single European Sky to overcome the fragmentation of the European ATC system

44 [ICAO_ANC11_3] Eleventh Air Navigation Conference, WP/170, SECURITY IN ATM COMMUNICATIONS

45 [ATN_Project] ATN Project, ATN End Systems, “Air/Ground Data Volumes In Europe”. File Ref.: ESTEF/T06/DEL/D10V.B_DATA VOLUMES.DOC. 7 July 2000.

46 [DL_RDMP_NA] Non-ATS applications. Roadmap for the implementation of data link services in European Air Traffic Management (ATM). Author: Helios Technology, Sofreavia, IATA, Integra Consult, Airbus

47 [AATT_2015] NASA AATT project, Communications System Architecture Development For Air Traffic Management & Aviation Weather Information Dissemination”. Subtask 4.6, Develop AATT 2015 Architecture, May 2000

48 [ATM_Context] EATM- Operating Concept of the Mobile Aviation Communication Infrastructure Supporting ATM beyond 2015, ATM Context, Ed. 1.0, April 2002

49 [LH_Traffic] LH e-mail to C. Rihacek, 02.03.2005, with a LH-internal estimate of AOC data traffic evolution

50 [ATNI-TF] DED6/ATN/ATNI-TF/DOC/25, ATN IMPLEMENTATION TASK FORCE, DRAFT ATN Scenario Definition, Issue 2.1, 22 July 1998

51 [NEW_SAT] EATMP- COM-SAT-REQ, New Generation Satellite Communication System(s) - Mission Requirements, Edition 1.0, 10 December 2003

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16. Abbreviations

4DTN 4 Dimensional Trajectory Negotiation

A/C Aircraft

A/G Air-Ground

A3E Double sideband modulation

AAC Aeronautical Administrative Communications

ACARS Aircraft Communications Addressing and Reporting System

ACC Area Control Centre

ACL ATC Clearances and Information (service)

ACM Aeronautical Communications Management

ACM Aeronautical Communications Management

ADS Automatic Dependent Surveillance

AEEC Airlines Electronic Engineering Committee

AENA Aeropuertos Espanoles y Navegacion Aerea

AFAS Aircraft in the Future ATM System

AFTM Air Traffic Flow Management

AIP Aeronautical Information Publication

AIS Aircraft Information Service

AMCP Aeronautical Mobile Communications Panel

amsl Above Mean Sea Level

AMSS Aeronautical Mobile Satellite Services

ANS Air Navigation Services

AoA ACARS over AVLC

AOC Airline Operations Centre

AOC Airline Operational Communications

APC Aeronautical Passenger Communications

APP Approach

ARINC Aeronautical Radio INCorporated

ASAS Airborne Separation Assurance System

ASE Application Service Element

A-SMGCS Advanced – Surface Movement Guidance and Control System

ASTERIX All-purpose STructured EUROCONTROL Radar Information eXchange

ATC Air Traffic Control

ATCC Air Traffic Control Centre

ATIS Automatic Terminal Information Service

ATM Air Traffic Management




ATN Aeronautical Telecommunications Network

ATS Air Traffic Services

ATSAW Air Traffic Situation Awareness

ATSP Air Traffic Service Provider

ATSU Air Traffic Service Unit

AUTOPS Autonomous Flight Operations

AVLC Aviation VHF Link Control

BCST Broadcast

BIS Boundary Intermediate System

CAA Civil Aviation Authority

CAP Controller Access Parameters (service)

CDMA Code Division Multiple Access

CENA Centre d'Etudes de la Navigation Aerienne

CFMU Central Flow Management Unit

CM Context Management

CMU Communications Management Unit

CNS Communication, Navigation and Surveillance

CoS Class of Service

COTRAC Common Trajectory Coordination (service)

CPDLC Controller Pilot Data Link Communication

CSMA Carrier Sense Multiple Access

D8PSK Differentially encoded 8-Phase Shift Keying

DAP Downlink of Aircraft Parameters

dBc dB relative to carrier

dBm dB relative to milliwat

DCL Departure CLearance

DEP Departure

D-FIS Data Link Flight Information Service

DLL Data Link Logon (service)

DLP Data Link Processor

DME Distance Measuring Equipment

DOC Designated Operational Coverage

D-OTIS Data Link Operational Terminal Information Service

DQPSK Differential Quadrature Phase Shift Keying

D-RVR Data Link Runway Visual Range (service)

DSB Dual Side Band




DSB-AM Dual Side Band Amplitude Modulation

DSC Downstream Clearance (service)

D-SIGMET Data Link Significant Meteorological Information (service)

DYNAV Dynamic Route Availability (service)

EANPG European Air Navigation Planning Group

EATMS European Air Traffic Management System

ECAC European Civil Aviation Conference

EIRP Equivalent Isotropically Radiated Power

ES End System

EUROCAE EURopean Organisation for Civil Aviation Equipment

fc Carrier frequency

FEC Forward Error Coding

FIR Flight Information Region

FIS Flight Information Service

FIS-B Flight Information Service - Broadcast

FL Flight Level

FLIPCY Flight Plan Consistency 8service)

FLIPINT Extension of FLIPCY service

FMG Frequency Management Group

FMP Flight Management Position

GACS Generic ATN Communications Service

GFSK Gaussian Frequency Shift Keying

GICB Ground-Initiated Control protocol B

GMSK Gaussian Minimum Shift Keying

GND Ground

GNSS Global Navigation Satellite System

GS Ground Station

HDLC High-level Data Link Control

HF High Frequency

HFDL High Frequency Data Link

HZ Homogenous Zone

IATA International Air Transport Association

ICAO International Civil Aviation Organisation

IDRP Inter Domain Routing Protocol

IFPS Initial Flight Plan Processing System

IFR Instrument Flight Rules




ILS Instrument Landing System

ITU International Telecommunications Union

kbps Kilobit per second

LACC London Area Control Centre

LACK Logical Acknowledgement

LLC Logical Link Control

LTCC London Terminal Control Centre

LTMA London Terminal Manoeuvring Area

MACC Manchester Area Control Centre

MACONDO Nickname for the EUROCONTROL study - Operating Concept of the Mobile Aviation Communication Infrastructure Supporting ATM beyond 2015

MC Multi-Carrier

MC-CDMA Multi-Carrier Code Division Multiple Access

MCST Multicast

MSK Minimum Shift Keying

MU Management Unit

NATS National Air Traffic Services

NAV Navigation

NAVSIM ATM/ATC & CNS simulation tool

NEAN North European ADS-B Network

NexSAT EUROCONTROL’s name for new generation satellite system

nm Nautical mile

NOTAM Notice to Airmen

OC Operational Concept

ODIAC Operational Development of Initial Air / ground Data Communications

OFDM Orthogonal Frequency Division Multiplexing

OPC Operational Control Communications

OSI Open System Interconnect

P2P Point to Point

PDC Pre-Departure Clearance

PHY Physical Layer (OSI model)

PoA Plain old ACARS

PPD Pilot Preferences Downlink (service)

ppm Parts per million

QoS Quality of Service

R/T Radio Telephony

RAD Radar




RCP Required Communications Performance

RCTP Required Communications Technical Performance

RF Radio Frequency

RGS Remote Ground Station

RSS Received Signal Strength

RT Radio Telephony

RTCA Radio Technical Commission for Aeronautics

RVSM Reduced Vertical Separation Minima

RWY Runway

RX Receiver

SAP System Access Parameters (service)

SARPS Specification And Recommended Practices

SATCOM Satellite Communications

ScOACC Scottish and Oceanic Area Control Ce

SHF Super High Frequency

SID Standard Instrument Departure

SITA Societe Internationale de Telecommunications Aeronautiques

SNDCF Subnetwork Dependent Convergence Facility

SP Service Provider

SQU Squelch (signal)

STAR Standard Instrument Arrival

STDMA Self-organising Time Division Multiple Access

TBD To Be Defined

TC Terminal Control

TCAS Traffic Alert and Collision-Avoidance System

TDMA Time Division Multiple Access

TIS Traffic Information Service

TIS-B Traffic Information Service - Broadcast

TMA Terminal Manoeuvring Area

TOD Top Of Descent

TP4 Transport Protocol 4

TWR ToWeR

TX Transmitter

UAC Upper Area Control

UAR Upper Air Routes

UIR Upper Flight Information Region




ULA Upper Layer

UTC Universal Time Co-ordinated

VDL VHF Digital Link

VDL2 VHF Digital Link Mode 2



VDR VHF Data link Radio

VFR Visual Flight Rules

VHF Very High Frequency

VLF Very Low Frequency

VOR VHF Omnidirectional Range

WAN Wide Area Network

W-CDMA Wideband CDMA

WGS84 World Geodetic System 1984

WP Work Package

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Documents

B-VHF Reference Environment