TanDEM-X: Science Exploration during the Phase C/D

Abstract

Topographic data building the base for information extraction which are of fundamental importance for the envi-ronment, economics, human security and to support decision makers. In order to provide reliable information’s of the Earth’s surface the DEM need to be up to date, consistent, accurate, high resolution and unrestricted available (GEOSS, IGOS, Earth Observation Summit, GMES). To fulfil these demands and requirements only a high per-formance Satellite concept will be capable to take the various attributes into account. At present the global coverage of topographic data at sufficiently high spatial resolution is currently inadequate or simply not available for scientific and governmental use. SRTM was the first step to meet the requirements of the scientific community for a homogenous, highly reliable DEM fulfilling the DTED-2 specifications. However, the acquired and processed high resolution DEM’s are not globally available (SRTM has mapped the earth be-tween 60 N and 56 S) and have wide gaps at lower latitudes. The concept of TanDEM-X has the potential to close the gaps, to fulfill the requirements and to provide the vital information’s for the variety of stakeholders. TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) has the goal of generating a global Digital Elevation Model (DEM) with an unprecedented accuracy corresponding to the DTED 3 specifications. This goal will be achieved by means of a second SAR satellite (TanDEM-X) flying in a tandem orbit configuration with TerraSAR-X (TSX-1). In this paper the focus is given to the scientific activities of the main objectives and the secondary objectives of the TanDEM-X satellite mission. The performance of X-band SAR interferometry for the derivation of a DEM over critical areas (e.g. dense vegetation cover and snow/ice) are evaluated. In particular the polarimetric capa-bilities are explored for the DEM generation. In addition the performance of Pol-InSAR at X-band is explored, as it is an important asset for a DEM correction over volume areas. This topic is a part of the science activities for the secondary objectives of the TanDEM-X mission.