First Results of Ground Moving Target Analysis in TerraSAR-X Data

Kurzfassung

The advanced high-resolution German SAR satellite TerraSAR-X is scheduled to be launched at the end of May 2007. Due to its daylight and weather independent applicability in combination with a large spatial coverage and a short acquisition time, SAR has become a promising tool for traffic monitoring in recent years. Ground Moving Target Indication (GMTI) techniques shall be applied to TerraSAR-X data in order to demonstrate the capability of a space borne SAR sensor to monitor traffic flows on highways. A series of GMTI experiments will be carried out during the commissioning phase of the TerraSAR-X satellite. In first trials, cars, which are equipped with special radar reflectors and GPS receivers, will be used as moving target references that are imaged in TerraSAR-X data takes. In a follow on experiment, arbitrary cars on motorways will be imaged simultaneously by TerraSAR-X and by an airborne high-resolution camera. Car tracks extracted from the series of the optical images shall serve as a reference for the evaluation of the TerraSAR-X moving target data in this case. The paper presents first results of the data evaluation. An experimental GMTI processing system is used to detect and measure moving targets in both single-channel and dual-channel data. The dual-channel data, which enable the application of well established GMTI methods like the Along-Track Interferometry (ATI) or Displaced Phase Centre Array (DPCA) techniques, are acquired either in the so-called “aperture switching” mode with virtual multiple receiving channels or in the Dual-Receive Antenna (DRA) mode with physically separated receiving channels. The paper reports on the analysis of the first experimental GMTI data by using different detection and measurement strategies. This includes the adapted processing of the SAR raw data with respect to the moving target signals, the incorporation of GIS data in the detection and measurement process and the application of different detectors for across- and along-track velocity components of the moving cars. The quality of the data is thoroughly analyzed and conclusions are drawn for the development and the performance of a fully automatic GMTI processing system for TerraSAR-X. Furthermore, an outlook on the planned experiments is given.