TerraSAR-X SAR System Verification

Kurzfassung

In 2007 TerraSAR-X, the first German Radar satellite for scientific and commercial applications, will be launched. The project is a public-private partnership between DLR and EADS Astrium GmbH. TerraSAR-X consists of a high resolution Synthetic Aperture Radar (SAR) at X-Band. The radar antenna is based on active phased array technology operating in multiple SAR modes (Stripmap, ScanSAR and Spotlight) with various polarizations. The highly advanced instrument allows the active configuration of many different instrument parameters and settings. The pre-launch activities for the TerraSAR-X system include the preparation of a verification plan to be accomplished during the commissioning phase. The aim of this plan is to define a procedure including all sub-systems to ensure optimum end-products (SAR images). The procedure involves tasks such as calibration, characterization/verification of 1) SAR-instrument, 2) SAR system performance, and 3) orbit and attitude determination, as well as 4) product verification. Due to the complexity and re-configurability of the system it is not possible to verify all possible combinations and settings. This makes the verification plan construction and the scheduling of the individual activities a non-trivial task requiring expertise for both the complete system and detailed sub-system level. The paper starts by introducing the areas covered by the system verification plan. These are combined in a block diagram for the basic SAR product verification flow. A detailed description of the philosophy behind the system verification plan is given. This is crucial to ensure proper interaction and to avoid conflicts during the detailed planning. The overall system verification plan is used to derive the verification matrix which identifies the tasks required for SAR System and Product release during the commissioning phase. Specifically, the bottom level outcome of this matrix are the commissioning phase data take and their sequence of acquisition. However, the matrix is also a driver for the development of the tools required for the evaluation/analysis of the data take measurements. The paper will present both the verification matrix as well as the overall commissioning phase schedule. First results and trends of the TerraSAR-X commissioning phase with respect to SAR system and SAR products verification will be presented. The paper gives an insight and is intended to be a valuable reference for the development of system verification strategies of state-of-the-art and future SAR systems.