AltiKa/SARAL project status

AltiKa/SARAL project status – OSTST - Hobart March 12-15, 2007

AltiKa/SARAL project statusAltiKa/SARAL project status

Jocelyne NOUBEL, CNES

Pierre SENGENES, CNES

AltiKa/SARAL project status – OSTST - Hobart March 12-15, 2007 2

SummarySummary

1. AltiKa/SARAL Mission features

2. SARAL Responsibility sharing

3. SARAL System overview

4. AltiKa/SARAL Mission requirements

Data products requirements Products definition

5. SARAL Project summary





4. AltiKa/SARAL Mission requirements Data products requirements Products definition



AltiKa/SARAL mission contextAltiKa/SARAL mission context

■AltiKa/SARAL program is an answer to the need expressed by IGOS and GODAE since 2000

« Continuity of high accuracy, high resolution near-real time observations of the ocean surface topography is required. At least, 2 simultaneous altimetric missions are required (including one of the Jason reference class) »

■Program approved on December, 2005 Altimetric Gap filler between ENVISAT & SENTINEL3 Research oriented mission :

- new, higher frequency, greater performance- potential new applications on ice, land, coast

areas …but with a consolidated architecture : conventional altimeter


AltiKa/SARAL mission scientific objectivesAltiKa/SARAL mission scientific objectives

■AltiKa/SARAL central objective Ocean meso-scale variability studies with an improvement of

vertical and spatial resolution Data assimilation in a global ocean model

■Contribution to : Operational oceanography Coastal altimetry Continental waters Inland ice sheet monitoring Light rainfall and clouds climatology Mean sea level Sea state observation and forecasting Geodesic reference system determination


AltiKa/SARAL mission and system highlights – AltiKa/SARAL mission and system highlights – OrbitOrbit

■AltiKa/SARAL mission orbit : same as ERS and Envisat orbits Polar (incl. = 98.55°) Sun-Synchronous orbit (6:00/18:00), 800 km

altitude, low eccentricity Ground track

repetitivity period : 35 days ground-track stability : +/- 1 km

Complementary to Jason2 ground-track in terms of spatial & temporal sampling


AltiKa/SARAL mission and system highlights – AltiKa/SARAL mission and system highlights – PayloadPayload

■ A single frequency Ka-band altimeter (35.75 GHz +/- 250 MHz) Improved vertical and spatial resolution

enhanced bandwidth (500 MHz) and increased PRF (~ 4kHz) antenna footprint : 8.5 km in Ka-band, 12 km in K-band

reduced ionosphere effect in Ka-band authorizes mono-frequency altimeter Ka-band limitations

no altimeter measurement for rain rate > 1.5 mm/h (data loss ~ 5% according to geographic areas) Specific measurement processing required in case of clouds or low rain rate situations (~ 10%)

■ A dual-frequency radiometer ( 23.8 GHz +/- 200 MHz & 37 GHz +/- 500 MHz ) required for wet troposphere correction on altimeter measurements embedded in the altimeter instrument : share the same antenna

■ POD system to achieve high accuracy orbitography performances DORIS

required for achieving high accuracy orbitography performances on low earth orbit in a precisely monitored reference frame (mean sea level analysis)

contribution to DORIS system performance and monitoring ( for the benefit of all altimetry missions using DORIS)

Laser Retro-reflector Array POD system calibration and guarantees minimum orbitography

■ for coastal/inland applications, real-time coupling of the altimeter with DORIS


AltiKa/SARAL mission and system highlights – AltiKa/SARAL mission and system highlights – Mission Ground SystemMission Ground System

■AltiKa Mission Ground System same definition of ocean products between JASON2 and AltiKa

products Same constraints for near real-time products processing and distribution

important synergy with JASON2 SALP/SSALTO developments Processing algorithms (retracking, radiometer troposphere correction,…) has to be

defined by the end of 2007 for ocean products, and at the beginning of 2008 for non-ocean products


AltiKa/SARAL program statusAltiKa/SARAL program status

■ AltiKa program has been approved by CNES Governing Board in December 2005

Authorization for Altimeter & Radiometer phase C/D commitment Funding for AltiKa development (AltiKa mission payload, CNES Mission Center upgrades,

system and science support studies) and for a 3-year exploitation (phase C/D/E) AltiKa payload was planned to be embarked on Oceansat3 ISRO satellite, for a launch foreseen

in mid-2009. But Oceansat3 launch is now postponed to 2011/12 …

■ May/June 2006 : CNES&ISRO proposition to embark AltiKa payload with Argos3 equipments, on a new platform, named SSB (Small Satellite Bus), which is being developed by ISRO

■ July/November 2006 : CNES&ISRO technical studies to assess the feasibility of this new satellite configuration SARAL satellite

■ December 2006 : CNES commitment to develop the Integrated Payload Module accommodating AltiKa and ARGOS-3 payloads

■ SARAL and ARGOS-3/SARAL MoUs signature by CNES and ISRO on February 23rd, 2007








SARAL sat. characteristics

# Mass : 350/400 kg

- SSB platform : ~200kg

- Payload Module : ~150 kg

# Power : 570 W (end of life)

- SSB platform : ~ 205 W

- Payload Module: ~ 195 w

# Size

- 0.98m x 0.98m X 2.6 m

-Solar panels : 1.2m x 1.4m (x2)

Present AltiKa & Argos-3 payloads accommodation Present AltiKa & Argos-3 payloads accommodation baseline on SSB platform : baseline on SSB platform :

SARAL (SAtellite with ARgos and ALtika)SARAL (SAtellite with ARgos and ALtika)

ARGOS UHF ANTENNA

MAGNETOMETER

X-BAND ANTENNA

TTC ANTENNA

DORIS ANTENNA

LRA

ARGOS L-BAND ANTENNA

ALTIKA ALTIMETER & RADIOMETER ANTENNA

SSB PLATFORM

INTEGRATED PAYLOAD MODULE

STAR SENSORS


CNES/ISRO SARAL Responsibility SharingCNES/ISRO SARAL Responsibility Sharing■ ISRO responsibilities

Project Management, shared with CNES

Overall SARAL system engineering PSLV Launch vehicle and services SSB Platform

SARAL Satellite integration and test

Ground System & Operations Satellite Operations Control Center S-band network stations X-band Hyderabad station Data communication network NRT and OFL products processing and distribution

to users within India Archiving

User interface

■ CNES responsibilities Project Management, shared with

ISRO Overall SARAL system engineering Payload

AltiKa payload ARGOS-3 payload

Integrated Payload Module Support for SARAL Payload Module

integration and test

Ground System & Operations X-band stations Data communication network AltiKa Mission Center NRT and OFL product processing software

development NRT product processing, archiving, distribution to

users outside India with the support of EUMETSAT OFL product processing and distribution to users

outside India DORIS product processing and distribution Archiving of all telemetry and products

ARGOS3 Data Processing and Distribution System User interface

ALTIKA System Coordination with other altimetry missions








SARAL system overviewSARAL system overview

SARAL Payload Data SegmentSARAL Space SegmentSARAL Satellite

AltiKa & ARGOS3 Missions Centers

Laser Community

Outside INDIA AltiKa

Users

Within INDIA AltiKa UsersSSB

Integrated Payload Module

Payload Interface Module

CNES Payload

ICU

Flight Operation

Control Center

ARGOS L-Band Ground Stations

Network

DORIS Beacons Network

EUMETSAT Center

Auxiliary data providers

ISRO Center

CNES Mission Center

IDSAltiKa NRT

AltiKa OFL

AltiKa NRT

SARAL X-Band Ground Stations

Network

SARALS-Band Ground Stations Network

ARGOS Processing

Center

ARGOS Processing

Center

ARGOS User

ARGOS User

ARGOS User

PSLV Launch vehicle

AltiKa NRT








AltiKa Data Products requirementsAltiKa Data Products requirements

■Data products Operational Service Specification (OSS) products (ocean type products)

Near-Real Time (NRT) products : OGDR Off-Line products (OFL) : IGDR, GDR

Non-OSS products 1 product for coastal zone & inland waters (studies in progress to define specific ground

retracking, content and format) 1 product for inland ice

■Data collection The system shall be design to assure for each day that 80% of data

collected on the satellite within 3 hours, and up to 100% of the data within 5 hours, can be made available to the users

Impact on on-board mass memory storage design, on ground station network design, set-up and operations, on communication network design, on ground processing performances

■Data latency Near-Real Time product (OGDR)

75% of the data taken shall be made available to the users within 3 hours from acquisition 95% of the data within 5 hours


AltiKa Data Products requirements - continuedAltiKa Data Products requirements - continued

■Data availability GDR shall contain 95% of all possible over-ocean data during the

mission life time, without any systematic gaps, taking into account the Ka-band constraints

5% of data loss due to rain rate > 1.5 mm/h according to geographic areas

10% of data to be processed with a specific retracking algorithm


AltiKa/SARAL Products definitionAltiKa/SARAL Products definition

■Products definition closed to the Jason-2 one ■All O/I/GDR products will have the same format and very close scientific

content IGDR vs. OGDR :

Orbit quality, improved pole location data, restituted DORIS USO frequency, improved altimeter/radiometer calibrations, analyzed meteorological fields, GIM ionospheric and dynamic atmospheric corrections applied

OGDR product not generated in case of altitude or time-tagging information from DORIS/DIODE not available

Fast Quality Control & Check for OGDR : elementary and automatic controls only, product delivered in any case

Quality Control & Check for IGDR : product not delivered in case of pbs detected; fully validated by DUACS processing; possible reprocessing

GDR vs. IGDR : Orbit quality, more accurate pole location data, more accurate dynamic atmospheric corrections GDR is fully validated by experts; dissemination to users only once validated

■Taken into account Jason-1 heritage, products will be split into several files :

One file close to current Jason-1 NRT-SSHA, limited to 1Hz sampling One file close to current Jason-1 I/GDR, containing 1Hz and 40Hz values One file close to current Jason-1 SGDR, containing 1Hz, 40Hz and waveforms

values. This file will not be generated in NRT


AltiKa/SARAL Product filesAltiKa/SARAL Product files

Product OGDR IGDR GDR Non-ocean surface DR

Content

geophysical level 2 productFast QC&C

geophysical level 2 productQC&C

fully validated geophysical level 2 product

geophysical level 2 products for non-ocean surface

Latency 3-5 hours < 3 days ~ 40 days 3 working days

1-Hz OGDR-SSHA IGDR-SSHA GDR-SSHA

1-Hz40-Hz

OGDR IGDR GDR

Waveforms S-IGDR S-GDR

Structure acquisition segment pass pass

Packaging segment day 7-day arc








SARAL Project summarySARAL Project summary

■ AltiKa/SARAL system PDR : end of 2007

■ Payload instruments delivery Altimeter&Radiometer instrument (antenna, electronic boxes) Flight Model: August 2008 DORIS receiver (BDR) Flight Model : April 2008

DORIS/AltiKa antenna flight model available since October 2006 LRA design and development phase : June 2007 to December 2008 ARGOS-3 equipments flight models delivery : July 2008 to December 2008 SARAL ICU and Payload Module design & development phase : July 07 to December 08

SSB spacecraft simulator delivery by ISRO to CNES : March 2008 CNES delivery of PIM electrical simulator to ISRO : July 2008

■ CNES Payload Module AIT : January 2009 – June 2009 ■ CNES Payload Module delivery to ISRO : July 2009

■ Development of AltiKa mission specific upgrades on the CNES altimetry multi-missions Center

Specification phase : until mid-2007 Development phase : from mid-2007 until end of 2008 Validation, Technical & Operational Qualification: until end of 2009

■ Satellite AIT and launch campaign : July 2009 – December 2009

Documents

AltiKa/SARAL project status