TanDEM-X DSM uncertainty measures and demonstrations

Abstract

SAR interferometry is a well-known technique to produce digital surface models (DSM). In the global scale, the qual-ity of these models significantly increased with the use of bistatic systems as for the TanDEM-X mission. DSM uncer-tainty can be measured in two scales: a global and a local one. A global scale analysis involves measures for the com-plete take, characterizing the whole correctness with a single parameter. A local scale analysis enters instead in the single elevation model cell, evaluating the quality obtained by dif-ferent terrains and media present in the take. A coherence analysis is a typical measure for InSAR models. Globally, a simple average gives an overall quality measure hint. Locally, it provides a measure of the DSM pixel height error. Unfor-tunately, this measure lacks in several aspects as not consid-ering unwrapping errors and not being valid for certain types of scattering. In this paper, various strategies for assessing elevation accuracy methods and demonstrate the different ca-pabilities of the bistatic TanDEM-X system are proposed for variegated terrain types.