Serving the TerraSAR-X Mission For Over Eight Years: Current Status and Recent Extensions of the TerraSAR-X Ground Segment

Kurzfassung

Since 2007, the TerraSAR-X mission provides high-resolution SAR data with high quality and an unprecedented geometric accuracy to both commercial and science users. The first satellite TSX was supplemented by a second, mostly identical, satellite TDX in 2010 for the generation of a global Digital Elevation Model (DEM) in the frame of the TanDEM-X (TerraSAR-X Add-On For Digital Elevation Measurements) mission. Since then the two missions share a joint space segment consisting of both TSX and TDX and a common ground segment which was first developed for TerraSAR-X and had been later extended for TanDEM-X. While TanDEM-X uses both satellites (nominally one in receive-only mode) for an acquisition, TerraSAR-X data are acquired by either one of the two satellites. It is this sharing of one ground segment which necessitated on-going updates of the TerraSAR-X ground segment in accordance with the TanDEM-X mission constraints. Furthermore, both satellites show a good health and resources, specifically the TSX which has considerably exceeded its nominal life time of 5.5 years by now, and thus justify on-going improvements to even better support user needs. This presentation summarizes the current SAR imaging modes and product portfolio and describes the recent ground segment system updates. Among these are the following: After having completed the global DEM data acquisition, the TanDEM-X mission currently focuses on the provision of radar data products for a number of new science technology related applications based not only on a bistatic, but also on a pursuit mono-static flight configuration. This pursuit mono-static flight configuration with its time lag of about 10 seconds between the two satellites allowed the processing of TanDEM-X acquisitions into TerraSAR-X product pairs which are offered to both the TerraSAR-X and the TanDEM-X science community. This includes fully polarimetric and along-track interferometry data acquired in the dual-receive antenna configuration. Receiving stations may be combined in a so-called TerraSAR-X ground station pool. Data takes ordered for such a station pool (instead of a single receiving station) are then planned for downlink to one or even several stations (in case of a partial downlink) by the mission planning leading to a much better exploitation of the limited downlink resources. Originally, the TerraSAR-X mission was not designed for near-real time (NRT) applications. Thus, the NRT functionality had to be included “as best as possible” within given constraints. Due to a growing demand for TerraSAR-X NRT products, the NRT capability was extended considerably over the last years. The TerraSAR-X product portfolio now supports maritime applications like ship and oil detection, wind and wave products are currently under integration. An improved mission planning and the downlink station pool concept leads to reduced product latencies.