Definition of ICESat Selection Criteria for their Use as Height References for TanDEM-X

Abstract

The TanDEM X satellite synthetic aperture radar (SAR) mission has the goal to deliver a high-precision global digital elevation model (DEM). The X band SAR interferometry (InSAR)-derived DEMs contain absolute and relative height errors that have to be minimized with the help of height references in order to achieve the specified accuracies. ICESat laser altimetry data are suited for this task, due to their accuracy and global distribution. In order to gain experience in the comparison between a radar-derived DEM and ICESat GLA14 elevation data, an X band DEM was acquired over a test region with the experimental airborne radar system (E SAR) of the German Aerospace Center (DLR) in Oberpfaffenhofen. Additionally a laser DEM of the area was used to verify the height accuracy claimed by previously published ICESat studies. The experiments described in this paper include the derivation of global ICESat quality selection criteria and the resulting density of selected ICESat samples over the Earth. These aspects are crucial for a successful TanDEM X DEM generation.