TanDEM-X: A Challenging Radar Mission for Generating a Next-Generation Earth’s Topography

TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurements) is a German Earth observation radar mission that consists of a synthetic aperture radar interferometer with two almost identical satellites flying in a closely controlled formation. With a typical separation between the satellites of 120 to 500 m interferometric data sets are acquired and processed to a global Digital Elevation Model (DEM) with 2 m relative height accuracy at 12 m posting. While the main mission phase for DEM data acquisition has been finished by mid-2014, the processing of the global (100% global land surface coverage including the poles) TanDEM-X DEM will be concluded in 2016. Final DEMs for more than 60% of all land masses are already available for scientific and commercial applications. The results achieved so far are well within the expected performance for the global DEM. A 15-month science phase of the TanDEM-X mission started in October 2014 which offers the opportunity to generate DEMs with even higher accuracy for selected areas, and to explore and demonstrate the new scientific applications of this unique mission. This paper provides an overview of the TanDEM-X and summarizes the current status and the quality of the available DEMs