TanDEM-X Bistatic SAR Processing

Abstract

In June, 2010 the German SAR satellite TanDEM-X (TerraSAR-X-Add-on for Digital Elevation Measurements) will be launched. Together with TerraSAR-X, launched June 15, 2007, it will form the first spaceborne bistatic SAR platform. Usually one of the satellite is transmitting (active satellite), while both are receiving. As both satellites fly in a helix orbit constellation, during a recording a satellite has to be passive, if the other one is close to the line of sight to the observation target at the moment of observation in order not to destroy the instruments of the other satellite, in other words they change their roles along the orbit. Even tiny differences in the instruments of both satellites can yield huge effects on final products. Within this paper we present the approaches of correcting thus differences. In the first part we explain, what variances in the satellite hardware are expected and how they are determined. In the second part we show, how the SAR processing copes with those differences.