11

Malaysia Real Time Kinematic GPS Network System

Malaysia Real Time Kinematic GPS Malaysia Real Time Kinematic GPS

Network SystemNetwork System

Geodesy Section, Mapping Division

Department of Survey and Mapping Malaysia

Contents

Historical Geodetic Infrastructure of Malaysia

The Move to Real-time Application using RTK GPS

Limitations of Classical RTK

MyRTKnet Concept

MyRTKnet Configuration

22

Historical Geodetic Infrastructure of Malaysia

MRT

BT68

Peninsular Malaysia Primary GPS Network

33

East Malaysia Primary GPS Network

Malaysia Active GPS System (MASS Network)

44

IGS Connection

GUAM

SHAO

WUHNKUNM

PIMO

BAKO

LHAS

IISC

COCO

KARR

NTUS

BAKO – Bakosurtonal, IndonesiaCOCO – Cocos Island, Australia

GUAM – Guam Island, USAIISC – Indian Institute of ScienceKARR – Karratha, AustraliaKUNM – Kunming, ChinaLHAS – Lhasa, Tibet

NTUS – NTU, SingaporePIMO – Mine and Geoscience

Bureau, PhilippineSHAO – Shanghai Observatory,

ChinaWUHN – Wuhan, China

KARR – Karratha

MASS DATA ON THE WEB

�GPS Data available after 24 hours

�Post-processing application

55

The Move to Real-time Application using RTK-GPS

Classical GPS and kinematic survey ( post-processed) can determine the precise position of a roving receiver relative to

a stationary station.

Classical GPS and kinematic technique requires office procedure/work before coordinate of a station can be derived

– time consuming

Real time kinematic (RTK) surveying is the latest dynamic GPS survey technique.

RTK-GPS utilize short observation times and enable you to move between station.

RTK-GPS can instantly determine the position of a roving unit

to centimeter-level accuracy using carrier phase positioning.

This technique is ideal for various application such as engineering, cadastral, topographic and detail surveys.

Limitations of Classical RTK

Limited range from single reference station

Errors grow with baseline length (ppm)

Reliability and performance decrease with distance to the next reference station

Dependency on single reference station

No integrity monitoring

No alarming

66

Single Base Station Surveying

Two receivers

Productivity loss

Potential gross error in establishing RS

Power supply

Communications/radio

Dial-in systems: Each reference station uses different number to call

MyRTKnet - RTK VRS Networking

77

Objectives of MyRTKnet

Geodetic Infrastructure for GNSS Real-time Positioning

Reference Frame and Coordinates System – GDM2000

Monitoring of Tectonic Movement

Geodynamic Studies

�The use of a network of reference stations instead of a single reference station allows to model the systematic errors in the region and thus provides the possibility of an error reduction.

�This allows a user not only to increase the distance at which the rover receiver is located from the reference, it also increases the reliability of the system and reduces the RTK initialization time.

MyRTKnet Concept

88

The network error correction terms can be transmitted to the rover in the following mode:

A Virtual Reference station mode as described below. This mode requires bi-directional communication. The basic advantage of this mode is that it makes use of existing RTCM and CMR standards implemented in all major geodetic rover receivers and thus is compatible with existing hardware.

The “Virtual Reference Station” concept is based on having a network of GPS reference stations continuously connected via data links to a control center. A computer at the control center continuously gathers the information from all receivers, and creates a living database of Regional Area Corrections.

These are used to create a Virtual Reference Station, situated only a few meters from where any rover is situated, together with the raw data, which would havecome from it. The rover interprets and uses the data just as if it has come from real reference station.

99

Implementation Principles of the VRS functional system solution

1. We need a number of reference stations (at least three), which are connected to the network server via some communication links.

2. The GPS rover sends its approximate position to the control center that is running GPSNet. It does this by using a mobile phone data link, such as GSM, to send a standard NMEA position string called GGA.

3. The control center will accept the position, and responds by sending RTCM correction data to the rover. As soon as it is received, the rover will compute a high quality DGPS solution, and update its position. The rover then sends its new position to the control center.

The network server will now calculate new RTCM corrections so that they appear to be coming from a station right beside the rover. It sends them back out on the mobile phone data link (e.g.GSM). The DGPS solution is accurate to +/-1 meter, which is good enough to ensure that the atmospheric and ephemeris distortions, modeled for the entire reference station network, areapplied correctly.

This technique of creating raw reference station data for a new, invisible, unoccupied station is what gives the concept its name, “The Virtual Reference Station Concept”

1010

VRS Data Flow

Reference station dataReference station data

streams back to thestreams back to the

server via leased linesserver via leased lines

or LAN/WANor LAN/WAN

VRS Data Flow

Roving receiver sends its Roving receiver sends its

position back to the serverposition back to the server

NMEANMEA

VRS position is VRS position is

establishedestablished VRSVRS

1111

VRS Data Flow

VRSVRS

NMEANMEA

Server uses VRS positionServer uses VRS position

to create to create „„correctedcorrected““

RTCM realRTCM real--time datatime data

RTCMRTCM

Rover surveys as inRover surveys as in

„„normalnormal““ RTK RTK –– but but

getting VRS data as if getting VRS data as if

from a nearby from a nearby

reference reference

stationstation

MyRTKnet Configuration

Network of 50 dual frequency GNSS referense stations in Peninsular Malaysia

Network of 28 dual frequency GNSS reference stations in East Malaysia

Control Centre at JUPEM Headquarter

1212

Peninsular Malaysia MyRTKnet

99.00 99.50 100.00 100.50 101.00 101.50 102.00 102.50 103.00 103.50 104.00 104.50 105.00

Longitude

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

5.50

6.00

6.50

7.00

La

titu

de

ARAU

BABH

BANT

BEHR

GETI

GMUS

GRIK

JHJY

JUML

KLAW

KUAL

KUKP

LGKW

MERS

MERU

PEKN

PUPK

SGPT

TGPG

TLOH

UPMS

USMP

UUMK

AYER

BAHA

BENT

CAME

CENE

GAJA

JRNT

KRAI

KROM

LASA

LIPI

MUAD

MUKH

PASP

PDIC

PRTS

PUSI

SBKB

SEG1

SETI

SIK1

SPGR

SRIJ

TERI

TGRH

TLKI

TOKA

East Malaysia MyRTKnet

110 111 112 113 114 115 116 117 118 119

Longitude (E)

1

2

3

4

5

6

7

Latitu

de

(N

)

UMAS

AMAN

SIBU

BINT

MIRI

LAB1

UMSS

SAND

TAWA

SEMA

KAPI

BEAUKENI

KUDA

TENO

JAMB

TUNKLAHA

SEMP

RANA

KBEL

TEBE

MUKA BELA

MARU

LIMBLAWA

LSEM

1313

MyRTKnet System Setup Reference Station Setup

²

²

²

²

²

²

1414

Reference Stations Components

Cisco 1721 router

Dlink 5port Switch 10/100Mbps

Trimble 5700 with Zephyr antenna (27 stations)

Trimble NetR5 with Zephyr antenna (51 stations)

Advantech Adam 6017 A/D module

Micromate Hybrid UPS System for 48 hours back up power

Micromate RS2888 Auto Restart System

Lightning protection

Moxa 5410 terminal server (27 stations)

Reference Stations Set-up

1515

Types of Monument Reference Station (Jerantut)

1616

Reference Station(Bukit Pak Apil)

Reference Station(Port Dickson)

1717

Reference Station (Tokai) Reference Station (Arau)

1818

Reference Station (Behrang) Control Centre Set-up

1919

Control Centre Configuration

Six GPSNet server with hot swap redundancyTwo Maintenance servers for system monitoring and data archivingTwo WEBROUTER servers for web server and data distribution.3745 router for access to the Internet and GITN cloud10/100/1000 switch to interconnect all componentsUPS to hold the system for power backup

Control Centre Components

2020

RTK Control Central Network

VRS Secondary

Server

VRS Primary

Server

Maintenance &

Archiving Server

GPStream

Server

Servers are installed on 19" System Rack

Functions:

- Win 2003 Srv OS- Splitter and Line

Relay

Functions:- Win 2003 Srv OS

- Base Station physical status monitor

- connectivity check to all base stations

- RINEX f ile recovery in event of communications

failure- Running UPS Service

- Internal HP DLT Tape Backup

- Access server accouning

3Com 24 port Gigabit Switch

Cisco 3745 Router

RTK*NET (IP VPN)

RTK BaseStation

Distributed to both VRS Servers

Functions:

- Win 2003 Srv OS- VRS application &

VRS Registry Mirror

- UPS Service

Ethernet Link``

19" SystemRack

1Mbpslease line

with ISDNbackup

64Kleased line

with ISDNbackup

Functions:- Win 2003 Srv OS

- VRS application- UPS Service

Ethernet Link`` Ethernet Link``

Communication Protocol

2121

Basic Requirement for Rover

GPS Receiver with FW and controller supporting VRS RTK corrections

Data Logger which run WindowsCE and supports PPP connections to ISPs or to GPRS – Trimble TSCe / ACU

However; if using older Trimble controllers or other third party equipment that do not have NTRIP Support built into the controller, an external PDA or computer is required

Mobile Phone with GSM Data / GPRS services

External PDA Connection

z

F 1 F 2 F3 F 4 F 5

Ne xt

M e n u En t er

Es c

8

5

2

9

6

3

7

4

1

0+ /- .

Ø

Here we have a TSC1 Here we have a TSC1

connected to serial port connected to serial port

1 of the 5700, a PDA 1 of the 5700, a PDA

connected to serial 3 of connected to serial 3 of

the 5700 and the cell the 5700 and the cell

phone connected to the phone connected to the

second serial port of second serial port of

the PDA.the PDA.

But how does this work?

The TSC1 instructs the 5700 that it is going to use a The TSC1 instructs the 5700 that it is going to use a

RTK VRS type of solution with the radio/corrections RTK VRS type of solution with the radio/corrections

source connected to serial port 3. We dial the cell source connected to serial port 3. We dial the cell

phone to connect to GPRS from the PDA and the phone to connect to GPRS from the PDA and the

PDA runs an application to select the NTRIP source PDA runs an application to select the NTRIP source

and then to decode the NTRIP formated corrections and then to decode the NTRIP formated corrections

and output the pure RTCM or CMR to the 5700.and output the pure RTCM or CMR to the 5700.

2222

VRS Data FlowT

T

T

T

T

T

Reference station data streams into the GITN Reference station data streams into the GITN

IP cloud via 64K leased lines.IP cloud via 64K leased lines.

From the GITN cloud, all From the GITN cloud, all

reference station data is reference station data is

immediately sent to immediately sent to

Seksyen Geodesi KL over Seksyen Geodesi KL over

a 1M leased line.a 1M leased line.

Remote users connect by Remote users connect by

getting onto the internet using getting onto the internet using

GPRS or GSM to ISP and GPRS or GSM to ISP and

selecting the IP address of the selecting the IP address of the

GITN Internet Gateway GITN Internet Gateway

202.75.44.154202.75.44.154 port 8080.

The GITN Internet Gatway The GITN Internet Gatway

forwards requests on port forwards requests on port

8080 to the GPStream 8080 to the GPStream

computer on which the computer on which the

NTRIP server is running.NTRIP server is running.

Upon receipt of the NMEA Upon receipt of the NMEA

GGA string from the GGA string from the

particular user, the system particular user, the system

will begin to stream network will begin to stream network

RTK corrections to the user.RTK corrections to the user.

Other users can also Other users can also

access the wenserver at access the wenserver at

202.75.44.154 for access to 202.75.44.154 for access to

customizable Rinex files for customizable Rinex files for

post processing and other post processing and other

services.services.

Courtesy of John Serink of Trimble

Coverage in Peninsular Malaysia

2323

Marudi

Kota Kinabalu

Kudat

Sandakan

Tawau

Kuching

Sibu

Bintulu

Sri Aman

Semantan

Belaga

Long Semado

Tungku

Ranau

Kota Belud

Malaysia RTK GPS Network System (MyRTKnet)

Keningau

TenomLawas

LimbangMiri

Labuan

Mukah

Long Seridan

Long Pa Sia

Semporna

Jambongan

Lahat Datu

Beaufort

30 km Radius Existing MyRTKnet Station

30 km Radius MASS Upgrade (2006)

30 km Radius New MyRTKnet Station (2006)

30 km Radius New MyRTKnet Station (2007)

Tebedu

Kapit

Coverage in Sabah & Sarawak

Within the Peninsular Malaysia RTK Net and Densed Network in Sabah and Sarawak and <30 km beyond, Network RTK will be functional

Where a reference station exists, within a 30Km range Single Base RTK will be available

Throughout the Peninsular Malaysia and parts of Sabah and Sarawak, DGPS Net will be operational

MyRTKnet Area Coverage

2424

Services Provide 5 difference services for users in Peninsular Malaysia

95% Network RTK coverage - VRS

95% Single Base RTK coverage

95% Post-process Virtual Rinex Data coverage

Provide Single Base RTK service for all reference stations in Sabah and Sarawak

Provide Rinex Data for all reference stations

100% DGPS coverage

Accuracy

VRS and Single Base RTK± 3 cm

DGPS coverage± 20 - 50 cm

Post-process Virtual Rinex Data< ± 3 cm

2525

Application

Engineering SurveyTopographic SurveyBoundary SurveyConstruction StakingUtility Extension SurveyFlood Survey Study and AnalysisPhotogrammetric Control Surveys

Application

GIS Applications

Control surveys for monumentation

Wetland Location Surveys

Soil Location Survey

Flagging Clearing Limits

Tree Surveys

Mapping and Navigation