Analysis and Evaluation of the DEM derived from TOPSAR Airborne Interferometric SAR System

Abstract

The aim of this paper is to assess the quality of Digital Elevation Models (DEMs) derived from Airborne Synthetic Aperture Radar (SAR) interferometry. An evaluation is made of the accuracy of the DEMs generated by the JPL/NASA TOPSAR interferometric SAR system, by comparing them with an accurate reference DEM derived from the digital photogrammetric processing of 1: 25000 aerial stereo photographs. The terrain in the test site location was relatively flat, with a variation in elevation ranging from 29 m to 115 m. DEMs generated from the acquired radar data were rotated and translated to overlay the reference DEM, allowing an analysis of the achieved height accuracy. The errors measured over 4.5 km x 2.5 km were 3.9 m rms for C-band interferometry DEM and 12.9 m rms for L-band interferometry DEM. The background on radar and SAR image formation, the principles and applications of SAR interferometry as well as the key factors that presently limit this technology are also presented.