ALTIKA OCEANSAT3 ISRO CNES mission

1
ALTIKA / OCEANSAT3 ISRO / CNES mission
Prepared by E. Thouvenot (CNES)
2
International 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

3
Altimetry missions from research to operational
Possible gap in 2007
AltiKa Oceansat3
NPOESS, GMES (S3)
To-day very good situation ! (5 satellites)
4
CNES involvement in altimetry
Reference mission Ocean Large scale
Complementing mission mesoscale, ice
Earth reference system
1990
experiment
SPOT2 (CNES) DORIS
ERS-1 (ESA) Altimeter algorithm
TOPEX/POSEIDON (CNES/NASA) Launcher DORIS
POSEIDON Mission Center
SPOT3 (CNES) DORIS
ERS-2 (ESA)
SPOT4 (CNES) DORIS
2000
Jason-1 (CNES/NASA) Satellite bus DORIS
POSEIDON Control Mission Center
ENVISAT (ESA) DORIS Altimeter Processing Archive
distrib.
SPOT5 (CNES) DORIS
2005
CRYOSAT (ESA) DORIS
Jason-2 / OSTM (CNES/NASA/EUMETSAT/NOAA) Satellit
e bus DORIS POSEIDON Control Mission Center
ALTIKA/OCEANSAT (CNES/ISRO) Altimeter,
radiometer, DORIS, Lra Process, archive
distrib.
PLEIADES (CNES) DORIS
SALP Altimetry and precise positioning service
operational
MERCATOR assimilation, forecast CNES / SHOM /
METEOFRANCE / IFREMER / CNRS / IRD
5
(No Transcript)
6
(No Transcript)
7
ALTIKA System Requirements

• Orbit selection
• Sun synchronous orbit
• Altitude range 700 900 km
• Ground track repetitivity lt35 days, gt15 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 gt 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)

8
AltiKa payload

• 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)

9
Altimetric measurement system
Orbit
Ionosphere
Troposphere
Altimeter beam
satellite Altitude
Altimeter measurement
Doris Beacon Earth Reference
Sea level
Topography
Geoid
Ellipsoid
10
AltiKa 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)
11
AltiKa applications
SeaState
Geodesy
Light rainfallclimatology
InlandIce
Meso-ScaleVariability(Central Objective)
MeanSea Level
OperationalOceanography
Inlandwaters
CoastalAltimetry
12
Ocean heat influence on Hurricanes
13
Dec. 2004 Tsunami as seen by Jason 1
14
Proposed OCEANSAT / ALTIKA Responsibility 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

• 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

15
AltiKa 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

16
CONCLUSION The AltiKa Payload as a 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.