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