ANALYSIS AND EVALUATION OF THE NASA/JPL TOPSAR ACROSS-TRACK INTERFEROMETRIC SAR SYSTEM

We have evaluated the accuracy of digital elevation models (DEM's) generated by the JPL/NASA TOPSAR synthetic aperture radar interferometer instrument by acquiring topographic radar data in the summer of 1992 over the National Training Center, near Ft. Irwin, California, and comparing the measurements to a very accurate digital elevation model derived for this area by the U.S. Army Topographic Engineering Center (TEC). Fiducial corner reflectors were deployed in the area, and their locations were determined to cm accuracy by the Defense Mapping Agency (DMA). DEM's generated from the acquired radar data were rotated and translated to precisely overlay the reference DEM, allowing an analysis of the achieved height accuracy. We present here a detailed description of horizontal and vertical errors and their characteristics. The standard deviation measured over a 5.6 x 7 km area was approximately 2 m, the corresponding figures for relatively hat areas were in the 1-2 meter range and for mountainous areas in the 2-3 meter range, consistent with theoretical expectations. We also discuss key factors that presently limit the system performance.