Topographic mapping using radar interferometry: processing techniques

A new processing algorithm for the NASA JPL TOPSAR topographic radar mapper is described. It incorporates extensive motion compensation features as well as accurate three-dimensional target location algorithm. The processor applies an algorithm to resolving the absolute phase ambiguity. This allows rectified height maps to be generated without any use of ground reference points. The processor was tested using data acquired with extreme aircraft motion so that performance could be evaluated under adverse conditions. The topographic maps generated by the radar were compared to digital elevation models (DEMs) derived using conventional optical stereo techniques. In one region, the RMS elevation deviations measured were less than the specified DEM accuracy, and, in the region covered by the more accurate DEM, errors varied from 2.2 m RMS in relatively flat terrain up to 5.0 m in mountainous area. The RMS difference between radar and DEM elevation over the 6.5-km by 22-km area covered by the more accurate DEM was 3.6 m