A Study on Integrated SAR Processing and Geocoding by Means of Time-Domain Backprojection

Geocoded products of synthetic aperture radar data are of great interest for many applications. The conventional processing chain, which leads to geographically referenced synthetic aperture data consists of two main steps: first, the raw data are focused and, in a second step, the resulting single look complex image is geocoded to the favoured coordinate system. We investigate a time-domain backprojection approach that replaces the two steps, focusing and geocoding, by one algorithm leading directly to terrain-geocoded images. The technique is evaluated with ENVISAT/ASAR image mode data. We assess the geolocation accuracy and the radiometric performance of dedicated point targets such as transponders and a corner reflector. In addition, we compare our findings with results from corresponding level 1 products processed at the European Space Agency (ESA), which were validated within the scope of ENVISAT/ASAR Cal/Val activities.