Updating GeoSAR for full-pol interferometric capability

GeoSAR is a single pass, dual frequency (X-band and P-band) interferometric mapping radar designed to map both top vegetation canopies and the terrain beneath the canopy. This system was developed from 1998–2003 as a joint effort of NASA JPL and EarthData under sponsorship of DARPA and NGA. The system is flown on a G-II aircraft and maps 10–12 km swaths simultaneously on both sides of the aircraft to generate high quality DEMs and imagery at both X-band and P-band. The system was later augmented with a nadir-pointing lidar profiler system to generate highly accurate control points that can be used in generating large area mosaics. Over the last 5 years the field of polarimetric interferometry has shown great utility in mapping the top of canopies and the underlying terrain with a great deal of accuracy at both L-band and P-band. This paper discusses an upgrade of the GeoSAR dual-pol (HH, HV) P-band interferometer to a fully polarimetric interferometer (HH, HV, VH, VV). We present both hardware and processor changes to the GeoSAR system needed for fully polarimetric interferometric operation.