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  • ----- Meeting Notes (2011/02/24 12:51) -----Sci Req is 3 yr in final orbit.
  • igarss11swot-vadon-callahan-psc-s3.110725.pptx

    1. 1. http://swot.jpl.nasa.gov<br />SWOT Ground SystemIGARSS – August 2011 <br />Helene Vadon (CNES, Toulouse) <br />Phil Callahan (Jet Propulsion Lab, California Institute of Technology) <br />
    2. 2. SWOT Ground System Outline <br />Introduction<br />SWOT mission<br />Mission phases <br />Ground segment overview<br />KaRIN Data Acquisition and Products<br />Acquisition characteristics<br />KaRIN processing <br />Data Products<br />Sizing estimates<br />Joint Ground System Development – Commonality levels and approach for the processing development<br />2<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />
    3. 3. SWOT Mission <br />Mission <br />Extraction of water surface heights over ocean and continental water bodies<br />The principal instrument isKaRIN, a Ka-band interferometric SAR system <br />Other instruments are a nadir altimeter, radiometer, and precision tracking systems (classical Jason Altimeter suite) <br />Main scientific requirements<br />Oceanography: Global coverage (< 78°) of oceans, sea surface height precision < 2 cm at approximately 1 km resolution  LR mode<br />Hydrology: Global inventory of rivers > 100 m (50 m) and lakes > (250 m)2, water surface height precision of the order of 10 cm (averaged over 1 km2), slope precision 1 cm/km (averaged over 10 km); average posting 50 m HR mode<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />3<br />
    4. 4. Mission Phases <br />Launch and Early Orbit Operations (~ 3 days) <br />Launch planned for late 2019 <br />Checkout / Commissioning (~ 30 - 45 days) <br />Fast repeat orbit at 3 (or 1) days for ~90 (or 30) days <br />For ocean sub-mesoscale <br />Calibration / Validation (Cal/Val) (3 – 6 months, covering Fast Repeat and Science Operations) <br />Transition to Science Orbit, Operations (~ 15 days) <br />Non-sun-synchronous, 22 day exact repeat, 970 km altitude, 78 deg inclination <br />Science Observations (Requirement = 3 years; starts ~4.5 months after launch) <br />Disposal and Ground System Closeout (= 3 months) <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />4<br />
    5. 5. SWOT Ground System Challenges <br />High precision for both ocean (1-2 cm) and hydrology (~10 cm) <br />Complete, accurate algorithms <br />Use of instrument and spacecraft calibration data <br />External corrections; Ancillary information <br />Large Data Volume – both telemetry and data products <br />Raw data downlink for land data. Requires >~ 600 Mbps X-band downlink <br />Data products posted at fine resolution: LR = 500 m, HR = 50 m (~100 giga-samples per cycle for LR+HR) <br />Likely Near Real Time requirements <br />Ocean from Jason suite similar to Jason series <br />Hydrology (floods, reservoirs) from KaRIN <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />5<br />
    6. 6. Architecture Diagram <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />6<br />S/C Bus<br />CNES Elements<br />NASA Elements<br />Joint Elements<br />Karin<br />Nadir Altimeter<br />Payload module<br />Radiometer<br />UPLINK: S/C & P/L Cmd. <br />DOWNLINK: Jason Suite Sci Data (Nadir Alt, Rad, GPS) and All Eng Telem <br />X band<br />TM<br />TBD Additional X-band Sta<br />KaRIN <br />Science Data <br />CNES S-band Network<br />CNES X-band Network<br />(also has S-band Uplink) <br />Science Data Center<br />To JPL: X-band data, TBD[KaRIN Eng] <br /> X-band Network <br />Center <br />JPL <br />Payload Operations Center <br />CNES<br />To CNES: <br />Ack. successful downlink <br />Payload commands <br />S/C Control Center (SCC) <br /> (Contractor)<br />To JPL: X-band data, S-band Sci, <br />s/c Telemetry, TBD[KaRIN Eng] <br />Payload Operations Center <br />JPL <br />Science Data Processing <br />Data exchange<br />Science Processing <br />Archive & Distribution<br />To JPL: Jason Suite L2. Cal/val. <br />To CNES: KaRIN TBD[L1b]. POD. Cal/val. <br />JPL <br />Science Data Archiving & Distribution <br />Ancillary Data: <br />Tropo model(s), Iono info, Tide model(s), DEM, SSH <br />
    7. 7. Ground System Elements (1 of 2) <br />Tracking Stations <br />CNES S-band stations: Downlink for Nadir Alt, Radiometer, DORIS, GPS (“Jason Altimeter Suite”, JAS); Engineering. Uplink commanding <br />X-band network (620 Mbps (nominal, min)): Downlink for high rate science (KaRIN), and associated Engineering data <br />Front End Networks <br />Network from X-band Data Center(s) to JPL and CNES operation centers. Minimum data rate to return all downlink within approximately 20 mins is >~ 300 Mbps (similar to downlink) <br />Network from CNES to JPL for S-band science and engineering data <br />Spacecraft Control Center (SCC, CNES/Contractor) <br />Real time monitoring of s/c and p/l via S-band housekeeping telemetry <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />7<br />
    8. 8. Ground System Elements (2 of 2) <br />Payload Operations Centers (POC) <br />JPL: Near Real Time health monitoring of KaRIN, GPS, Radiometer. Determine X-band data quality, need for replay.<br />CNES: Near Real Time health monitoring of Jason Altimeter Suite <br />Science Processing Centers <br />JPL: Processing of KaRIN, POD <br />CNES: Jason Suite, POD <br />Data Archiving and Distribution Centers <br />JPL: PODAAC <br />CNES: AVISO <br />Project Data Distribution Networks <br />JPL-CNES link <br />Science Processing Centers to Archiving/Distribution Centers <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />8<br />
    9. 9. SWOT Ground System Outline <br />Introduction<br />SWOT mission<br />Mission phases <br />Ground segment overview<br />KaRIN Data Acquisition and Products<br />Acquisition characteristics<br />KaRIN processing <br />Data Products<br />Sizing estimates<br />Joint Ground System Development – Commonality levels and approach for the processing development<br />9<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />
    10. 10. KaRIN Data Acquisition <br />IGARSS11 - SWOT Ground System<br />10<br />Vsat<br />A few km<br />Vsat<br />Classical Nadir Altimetry<br /><ul><li>Resolution = Swath(~ 10km)
    11. 11. Inter-track at equator ~ 100km</li></ul>6 -10 km<br />50km<br />2.5 m<br />70m max<br />50km<br />KaRIN altimetry<br /><ul><li>Resolution << Swath :</li></ul>(2.5m x 10m to 70m) << ~100km <br /><ul><li>Almost full coverage</li></ul>20 km<br />120 km<br />2011/07/25 s3 psc<br />
    12. 12. KaRIN Processing Steps <br />SAR processing (range and azimuth compression)<br />Interferometric processing (co-registration, computation of interferometric phase and coherence)<br />Application of acquisition geometry: geolocation, precise orbit determination, correction of roll, baseline variations<br />Propagation corrections: tropospheric, ionospheric delay <br />Interferogram flattening/correction, land phase unwrapping <br />Estimation of geophysical parameters: water surface detection (HR only), computation of water surface heights, slopes etc. <br />Establish/refine floodplain DEM (annually (goal) or mission) <br />High-level and multi-temporal processing is a Science Team activity <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />11<br />
    13. 13. Data Products (1 of 4) <br />Level 0 ( ~ 1 TB/day) <br />Ocean KaRIN: partial interferograms (Raw to partial interferograms processing onboard)<br /> Hydro KaRIN: raw data<br /> Nadir altimeter and Radiometer data: instrument raw data<br /> GPSP and DORIS data: POD raw data <br />Level 1: Nadir Alt, Radiometer, KaRIN ( ~ 10-12 TB/day) <br />L1a: Engineering unit conversion, calibration data separated for additional processing <br />L1b: Final instrument level data with calibrations appended <br />Ocean: 9-11 onboard interferograms (1km x 1 km), correlations, amplitudes with instrument calibrations and phase variations corrected combined <br />Hydro (HR): KaRIN phase flattened Interferograms<br />Altimeter, radiometer compliant with Jason-2 Science Data record processing (SGDR)<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />12<br />
    14. 14. High Level Data Products (2 of 4) <br />L2A<br />Ocean KaRIN : As L1B + Geophysical corrections. Nadir data merged for cross calibration. <br />Ocean Crossover Attitude Correction: Estimate attitude errors from ocean crossovers for correcting both ocean and land data. <br />Intermediate Hydro: L1B + water mask detection; rain, snow, ice/frozen detections <br />L2B (standard distributed products)<br />Remark:Every field will be associated with an uncertainty estimate<br />Ocean (LR, fixed swath grid, 500 m; ~ 3 G-samples/day): <br />Sea surface (SS) heights in latitude/longitude grid<br />SS slope at each point of the grid <br />Sigma 0<br />Wind speed<br />Ocean Sea Wave Height on same grid (goal)<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />13<br />
    15. 15. High Level Data Products (3 of 4) <br />L2B (standard distributed products) (continued) <br />Hydrology (HR, regions, network, 50 m; TBD[80] GB/day): <br />Geo-localized water mask (lakes > (250 m)^2, rivers >100 (50) m)<br />Estimated water elevations (same sampling as mask) -> Triangular interpolated network (+ uncertainties)<br />Topographic map of the flood plain surrounding the water surface and channel cross sections (requirement to be produced by the end of the mission; goal - annually)<br />Ocean Nadir: Similar to current Jason-2 SGDR <br />NRT (goal)<br />Ocean: as Level 2 products but with lower accuracy (quick-look orbit and calibration using past cross-overs)<br /> Hydro: Level 1 products (SLC + interferogram), no calibration data, use of ancillary DEM for phase flattening<br /> Nadir products: OGDR/ IGDR products (see Jason-2 OSS)<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />14<br />
    16. 16. High Level Data Products (4 of 4) <br />POD – determined from GPS and DORIS <br />Ancillary Data – updated daily <br />Atmospheric models: Dry Tropo (surface pressure), Wet Tropo (water vapor) <br />Input to ionospheric model <br />Geophysical Models – updated infrequently <br />Mean Sea Surface, Geoid <br />DEM, Water mask (a priori, then self derived) <br />Elastic Ocean Tides, Earth Tides, “Pole Tide” <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />15<br />
    17. 17. Sizing Considerations <br />Global coverage, continuous acquisition<br />Acquisition hypothesis <br />Sea 70%, Land 30% => <br />In the average orbit, KaRIN will acquire 67 GB of data to be transmitted to ground=> ~1 TB /day (~ 99% HR data)<br />Archive Plan <br />Nominal mission duration: 3 years<br />Long term archive of (main contributors in terms of volume) Raw HR, SLC (L1A), Interferograms + masks (L2A), Geo-localized hydro products (L2B) => ~10 000TBytes <br />Comparison to other missions <br />CNES: more than 5 times Pleiades satellite archive (dual civilian/defense optical imagery, to be launched soon)<br />NASA: similar to proposed DESDynI (Earth deformation and sea ice from L-band Radar repeat pass interferometer) <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />16<br />
    18. 18. SWOT Ground System Outline <br />Introduction<br />SWOT mission<br />Mission phases <br />Ground segment overview<br />KaRIN Data Acquisition and Products<br />Acquisition characteristics<br />KaRIN processing <br />Data Products<br />Sizing estimates<br />Joint Ground System Development – Commonality levels and approach for the processing development<br />17<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />
    19. 19. General Levels of Commonality <br />Commonality between two processing systems may be achieved at different levels<br />Commonality of the full production system (clone, e.g. Jason)<br />Prevents existing systems reuse. Not necessary for SWOT development <br />Commonality of the algorithms, software, and products<br />Products are guaranteed 100% similar. May be the right level. <br />Commonality of specification and reference data<br /> Independent developments. Risky because reference data does not cover all cases so products will not be 100% similar.<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />18<br />
    20. 20. General Algorithm Development Approach <br />Science processing algorithms will be developed primarily by supplier of each instrument <br />Algorithm flow will be iterated within entire development team <br />Data product definitions will be iterated with Science Team <br />Algorithm testbed will be set up and prototype processing developed <br />Testbed will read and write specified products <br />Test data will be (or emulate) specified products <br />After initial development cycle, algorithm specifications will be written for review by System Engineering team and selected subset of Science Team <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />19<br />
    21. 21. CNES Usual Development Approach <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />20<br />GS Infrastructure development<br />Operational chain development<br />Algorithmic prototyping<br />Algorithms prototyping activities and operational chain development are relatively independent<br /><ul><li>The scope of prototype development may be larger than scope of operational system development
    22. 22. But not true the other way: prototypes are needed to build the reference data for the validation of the operational chain </li></li></ul><li>JPL Usual Development Approach <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />21<br />GS Infrastructure development<br />Processing framework from previous projects will be leveraged <br />Operational chain development<br />Algorithmic prototyping<br />Algorithm and framework developers will agree on interfaces and control mechanisms <br />Testbed prototype will incorporate as much of the processing framework as possible <br />Notes: <br />NRT processing will be based on standard algorithms but may not use the processing framework <br />Existing POD processing will be implemented in project environment <br />
    23. 23. Commonality Approach for SWOT <br />Complementary prototyping activities will be conducted by JPL and CNES<br /> The order and nature of the processing steps of the operational LR and HR processing chains will be discussed and agreed on by JPL/NASA and CNES <br /> The detailed work share is not yet defined, but the operational algorithms and related binary code will be common<br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />22<br />
    24. 24. Backup <br />IGARSS11 - SWOT Ground System<br />2011/07/25 s3 psc<br />23<br />
    25. 25. SWOT 40 month Mission Timeline <br />24<br />Backup or here ? <br />Mission Phase<br />Launch<br />(02 Dec 2019)<br />EOM <br />(Mar 2023)<br /> In-Flight Assessment Meeting<br />Initial Phase<br />LEOP ~3 days: nominal s/c state<br />4 weeks<br />Fast sampling orbit acq<br />Checkout / Commissioning (up to L + ~65 days)<br /> In-Flight Assessment Meeting<br />First Verification Workshop<br />Calibration/<br /> Validation Period<br /><ul><li>Final Verification workshop
    26. 26. (Sci Team meeting at L + 12 months </li></ul>Cal/Val<br />Science Observation (36 months)<br />Decommissioning<br />( ~ 30 days)<br />~ 2-4 weeks<br />Nominal Orbit Acquisition<br />Orbit<br />Injection<br />Science Processing Closeout<br />Fast Repeat<br />TBD[3, 1 day; near 22 day]<br />Operational Phase<br />22-day repeat, 78 deg, 970 km (non-sun-sync) <br />Science<br />Disposal<br />Eclipse Season (illustration only)<br />Calendar Years<br />2020<br />2021 <br />2022 <br />2019 <br />2023 <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />
    27. 27. Science Operations (1 of 1) <br />Science data collection phase starts ~ 4.5 months after launch. Collect data for 3 full years in observational orbit <br />Full validation period: 6 months of data in science orbit + 2 months processing, internal review <br />Science Team meeting to assess initial data products ~ 12 months after launch <br />Processing update based on Science Team assessment implemented ~ 2 months after meeting <br />Ready to reprocess all data with updated system ~ 16 months after launch. <br />Science Requirements on Reprocessing (assume “caught up” at 24 months) puts requirements on total Processing Center throughput (Suggest project aggregate > 5x). Budget/scenario: <br />Cal/val data (~3 months) – as science phase starts <br />Initial science phase data (~12 months +3 months cal/val) – within TBD [< 3] months. Result: at ~20 months after launch version 2 of all usable data available. Support Science Team meeting at ~24 months to validate data <br />End of nominal mission: Reprocess all data a second time with SDS update done from ~ 30 – 36 months after launch; takes 6 – 8 months (runs until 3 months after end of mission [assumes no extended mission]) <br />2011/07/25 s3 psc<br />IGARSS11 - SWOT Ground System<br />25<br />