Geocoding of fast-delivery ERS-l SAR image mode product using DEM data

Abstract

An algorithm for geocoding and radiometric correction of ERS–1 Synthetic Aperture Radar images by using Digital Elevation Model data is described a.nd applied to images over a mountainous area in Norway. Several images covering the same area are calibrated and geocoded into a UTM map projection and the results are evaluated against map and i/1 situ measurements. The map to SAR geometric precision is given by a rms value of 54m in the casting direction and 45m in the northing direction. The SAR to SAR geometric precision is given by a rms value of 43m in the casting direction and 44m in the northing direction. Estimates of the radar backscatter coefficient are extracted from the geocoded SAR backscatter images. Obtained values for wet snow–13dB and for dry snow–7dB which agrees favourably with earlier radar measurements and theory.