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ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 1
ALTIKA / OCEANSAT3 ALTIKA / OCEANSAT3 ISRO / CNES missionISRO / CNES mission
Prepared by E. Thouvenot (CNES)
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 2
International context for altimetry missionsInternational context for altimetry missions
• Need expressed by IGOS (Integrated Global Observing Strategy) &GODAE (Global Ocean Data Assimilation Experiment) since 2000:
« Continuity of high accuracy, high resolution near-real time observations of the ocean surface topography is required. At least, 2 simultaneous altimetry missions are required (including one of the Jason reference class) »
• Consequence : need to prepare a post-ENVISAT mission that would fly at the same time as JASON2
• Additional requirements to take into account : - post-GODAE & IGOS needs about performance improvement (high resolution altimetry & coastal altimetry)- GMES needs
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 3
Altimetry missions : from research to operationalAltimetry missions : from research to operational
In orbit Approved Planned/pending approval
97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12
03/2001
Proposed Scenario
66 deg inclinat ion
EUR-US M2
High inclination
ALTIMETRIC MEASUREMENTS: SSH, SWH, WIND SPEED AT NADIRPOSSIBLE SCENARIO FOR OPERATIONAL CONVERGENCE BETWEEN THE USA & EUROPE
G F O
GODAE
TOP EX-POS EIDON
ERS-2
ENVISAT
* An oc ea n circula tio n o bserv ing s ys te m requires tw o altim eter miss io ns s imultane ous ly in orbit fo r pro pe r s ampling/cove rag e .* US co ntribution to jo int o peratio nal sy stem part o f NPOESS (a ltimetry is part o f NPOES S base line)
JASON-1
JASON-2
US-Europe a nConverge nc e
on jointope ra tional sys te m
(2 orbits)
Po s t-Envis at (Alt iKa ?)
EUR-US M1
AltiKa Oceansat3
NPOESS,GMES (S3)
Possible gapin 2007
To-day : very good situation ! (5 satellites)
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 4
CNES involvement in altimetryCNES involvement in altimetry
TOPEX/POSEIDON (CNES/NASA)
LauncherDORIS & POSEIDON
Mission Center
Reference missionOcean Large scale
Complementing missionmesoscale, ice
Earth reference system
SPOT2 (CNES)DORIS
SPOT3 (CNES)DORIS
SPOT4 (CNES)DORIS
SPOT5 (CNES)DORIS
1990
2000Jason-1 (CNES/NASA)
Satellite busDORIS & POSEIDON
Control & Mission Center
ERS-1 (ESA) Altimeter algorithm
ENVISAT (ESA)DORIS
Altimeter ProcessingArchive & distrib.
ERS-2 (ESA)
experiment
operational
CRYOSAT (ESA)DORIS
Jason-2 / OSTM (CNES/NASA/EUMETSAT/NOAA)
Satellite busDORIS & POSEIDON
Control & Mission Center
ALTIKA/OCEANSAT(CNES/ISRO)
Altimeter, radiometer, DORIS, Lra
Process, archive & distrib.
SALP : Altimetry and precise positioning service
MERCATOR : assimilation, forecastCNES / SHOM / METEOFRANCE / IFREMER / CNRS / IRD
PLEIADES (CNES)DORIS
2005
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 5
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 6
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 7
ALTIKA System RequirementsALTIKA System Requirements
Orbit selection : Sun synchronous orbit Altitude range : 700 – 900 km Ground track repetitivity : <35 days, >15 days
Ground system : Altika payload near real time monitoring and commands : ISRO OCEANSAT control
center Altika Payload expertise and long term monitoring : CNES SALP Science and auxiliary telemetry recovery and distribution : ISRO OCEANSAT control
Center Sizing parameter : data latency
– Three hours max required between data measurements on-board and near real time distribution to operational users (for > 75% data)
– Implies science data dump once per orbit– One hour for data exchange and processing
Science Data Processing, Archive and distribution ISRO Mission Center CNES SALP (+ EUMETSAT TBC)
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 8
Ka-band altimeter with enhanced bandwidth ionospheric effects are negligible better vertical resolution error budget improvement Ka-band (35 GHz) authorizes a compact, lightweight instrument easier to accommodate on a wide range of satellite buses
Dual-frequency radiometer (24/37 GHz) required for tropospheric correction derived from Madras (Megha-Tropiques) developments
Laser Retro-reflector Array useful for orbitography and system calibration
DORIS required for achieving adequate orbitography performances in low earth orbit (oceanography need) enable to have similar performance than reference missions like T/P, JASON, ENVISAT required for mean sea level analysis and coastal/inland applications (real-time coupling with altimeter)
AltiKa payloadAltiKa payload
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 9
OrbitOrbitOrbitOrbit
Sea levelSea level
Doris BeaconDoris BeaconEarth ReferenceEarth ReferenceDoris BeaconDoris BeaconEarth ReferenceEarth Reference
Altimeter beam
EllipsoidEllipsoid
GeoidGeoid
Ionosphere
Troposphere
TopographyTopography
Altimetric measurement Altimetric measurement systemsystem
Altimeter measurementAltimeter measurementAltimeter measurementAltimeter measurementsatellitesatellite AltitudeAltitudesatellitesatellite AltitudeAltitude
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 10
0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.5
3
3.5
4
4.5
H1/3 (m)
Ran
ge n
oise
1 s
econ
d (
cm)
Ku/C320
Ku
Ka
AltiKa performanceAltiKa performance
Large improvement wrt current altimetry missions :- altimetrer noise 3 times better on ocean- very good coastal and inland (rivers, lakes) performance
Comparison of tracking performance on western Corsica coastline:-AltiKa alone (at left)-AltiKa + DIODE/DORIs (at right)
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 11
Meso-ScaleMeso-ScaleVariabilityVariability
(Central Objective)(Central Objective)
Light rainfallLight rainfallclimatologyclimatology
MeanMeanSea LevelSea Level
InlandInlandIceIce
SeaSeaStateState
OperationalOperationalOceanographyOceanography
CoastalCoastalAltimetryAltimetry
GeodesyGeodesy
InlandInlandwaterswaters
AltiKa applicationsAltiKa applications
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 12
Ocean heat influence on HurricanesOcean heat influence on Hurricanes
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 13
Dec. 2004 Tsunami as seen by Jason 1Dec. 2004 Tsunami as seen by Jason 1
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 14
Proposed OCEANSAT / ALTIKA Proposed OCEANSAT / ALTIKA Responsibility SharingResponsibility Sharing
ISRO responsibilities: Project Management Launch vehicle Satellite development, IRS bus Payload :
TBD Satellite integration and test Ground System & Operations
Satellite Operations Control Center Command & Data Acquisition Stations
(TBD) Near Real Time product processing Product distribution Archiving Ground network for housekeeping
data, science data and products exchange
User interface
ISRO responsibilities: Project Management Launch vehicle Satellite development, IRS bus Payload :
TBD Satellite integration and test Ground System & Operations
Satellite Operations Control Center Command & Data Acquisition Stations
(TBD) Near Real Time product processing Product distribution Archiving Ground network for housekeeping
data, science data and products exchange
User interface
CNES responsibilities: Project Management Payload
Nadir Ka band Altimeter Nadir microwave radiometer DORIS tracking receiver Laser retro reflector array
CNES support for Payload integration and test
Ground System & Operations Product processing tool development Off line global product processing and
distribution Archiving Ground network for housekeeping data,
science data and products exchange EUMETSAT responsibilities (TBC) :
– Near Real Time global product processing, archiving, distribution and user interface
User interface ALTIKA System Coordination with other
altimetry missions
CNES responsibilities: Project Management Payload
Nadir Ka band Altimeter Nadir microwave radiometer DORIS tracking receiver Laser retro reflector array
CNES support for Payload integration and test
Ground System & Operations Product processing tool development Off line global product processing and
distribution Archiving Ground network for housekeeping data,
science data and products exchange EUMETSAT responsibilities (TBC) :
– Near Real Time global product processing, archiving, distribution and user interface
User interface ALTIKA System Coordination with other
altimetry missions
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 15
AltiKa development planAltiKa development plan AltiKa instruments are based on proven concepts and already developed
sub-systems: innovative & mature solutions
AltiKa payload development plan discussed with ISRO in the frame of OCEANSAT-3 mission
Launch planned on 1st semester 2009 Nominal lifetime : 3 years OCEANSAT3 payload not yet decided : candidates are OCM sensor (probably), TIR
sensor (possibly), Wind scatterometer (may be difficult to combine with AltiKa), ... AltiKa payload current status
Delta phase B : January 2005 to October 2005(Very fruitful technical meetings with ISRO on May 16-17)
Phase C/D : October 2005 to June 2008 DORIS Phase C/D started since January 2005
ET-3rd Indo-French Workshop on Megha-Tropiques, October 2005 16
CONCLUSION: The AltiKa Payload as CONCLUSION: The AltiKa Payload as a precursor to future altimetry systemsa precursor to future altimetry systems
• AltiKa has been designed to solve the « post-ENVISAT altimetry gap » issue and reach the mission objectives derived from post-GODAE/IGOS requirements, in complement to the operational Jason-2 mission
• At a longer time scale, AltiKa payload could be the core of a permanent, operational, high-resolution altimetry system, flying as a multi-microsatellite system embarking the same payload, or as a combination of microsatellites and minisatellites.