KaSPAR: Ka-band SWOT Phenomenology AirborneRadar
Delwyn Moller
NASA SWOT SWG Meeting 3/2/2010
5.5 km
15 k
m
Heritage: GLISTIN Ka-band Airborne Interferometer
Correlation Height Accuracy Map (m)
7.5km
First demonstration of millimeter-wavesingle-pass interferometry
• Successfully deployed to Greenland May ‘09.• Major step forward in technology development and
technique demonstration• Processing refinement and development at JPL will
be direct heritage for KaSPAR• Data collected en-route for SWOT for hydrology and
sea-ice.- Fringes observed and good off-nadir coherence- 31o boresite so aircraft rolled toward nadir and
“crabbed”
NASA SWOT SWG Meeting 3/2/2010
A Ka-band SWOT Phenomenology Airborne Radar (KaSPAR)
Calibration/Validation Sensor• The high-precision swath elevation
mapping capability will enable calibrationand validation of SWOT with 3Dmeasurements not currently achievable
Primary measurement product:• High accuracy elevation maps with ~5km
swath (at 35kft) over ocean- Traditional altimeter height retrieval to
provide tie points for swath edges
Dedicated Science Campaigns?- To be discussed by the SWG today
Phenomenology• Multiple (elevation & temporal) baselines replicate and
fully characterize SWOT sampling and geometry
• Gather pre-mission data for SWOT over specific andvaried science targets for:
- Classification (land/water and further)- Predicting performance and interpretability to
extend the science impact beyond the missionrequirements
- Penetration into snow for cryospheric applications
• Provide high resolution spatial measurements of:- Water temporal correlation- Elevation (both land and water)- Surface backscatter- Vegetation attenuation
NASA SWOT SWG Meeting 3/2/2010
NRCS assumes ocean 6m/s winds => azimuth resolution~80m
* No calibration other than aircraft roll-knowledge used.Range resolution 20m
** calibrated for systematic errors using altimeter. Rangeresolution 50m
Description and Performance
Parameter Value Unit
Center Frequency 35.75 GHz
Peak Transmit Power 40 W
Platform Height 35 kft
Swath Coverage “inner” “outer”
1.45.0 km
Bandwidth “inner” “outer”
200 (min)80 (min) MHz
Mean height error “inner” “outer”
1.2*
2.3**cm
Incidence angles “inner” “outer”
1-54-27 deg
• Two sets of transmit antennas:1. Illuminate inner (SWOT geometry) & outer
swath to provide wide-swath coverage2. Overlapping beams for inter-calibration
• Multiple elevation and temporal baselines “near-nadir”
• Initial candidate aircraft NASA King Air butdesign aircraft independent- Swath performance generally better as
altitude increases
NASA SWOT SWG Meeting 3/2/2010
Random error across swath
Schedule and Programmatics…
• Currently funded under a Phase II NASA SBIR• Working closely with JPL/ SWOT project to maximize relevance• Aiming for system delivery end of Summer 2011 • First flights Fall 2011
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