TanDEM-X Mission: SAR Image Coregistration Aspects

Abstract

SAR image coregistration is of fundamental importance for accurate Digital Elevation Model (DEM) generation. In this paper the coregistration algorithm for the TanDEM-X Mission is presented. Because of the parallax, a range shift variation of several samples over range appears. The use of coregistration polynomials is not a suitable solution due to the high resolution of the system, therefore a new two-step algorithm is proposed: a geometrical a-priori shift estimation followed by an optimized signal-based method. Moreover, an outliers elimination module is described. Results with TerraSAR-X repeat-pass data are shown.