Results from the SRTM Calibration Phase

Abstract

In February 2000 the Shuttle Radar Topography Mission mapped 80% of the earth surface using the first space borne single pass SAR interferometer. On board were two radar systems, a US system operating in C-band and a German/Italian system operating in X-band. At the German Aerospace Center (DLR) the global X-band data set is processed to a global digital elevation model (DEM). Even if the single pass mode provides better coherence than previous dual pass missions, the high complexity of the system poses a challenge on calibration. All electric and geometric subsystems must be calibrated precisely to ensure global homogeneity. The paper deals with clock synchronization, phase dependence on temperature and with motion errors caused by the space shuttle platform. The paper further describes the major error sources and the methods applied for compensation. First results will be shown that predict the global quality of the DEM. The results are illustrated with sample products.