Analysis on TerraSAR-X Spotlight Scene Size and Sliding Spotlight Azimuth Ambiguity Ratio

Abstract

The Technical Note presents an investigation about the scene size of TerraSAR-X Spotlight mode. The TSX spotlight mode was designed in order to ensure a fixed scene size for all incidence angles, i.e. 10kmx10km for Spotlight and 10kmx5km (range x azimuth) for High-Resolution Spotlight. Additionally a maximum steering range from -0.75° to +0.75° was defined in order to ensure the best performance w.r.t. azimuth ambiguities. But depending on the incidence angle also a larger scene size is possible in far range. If the maximum nominal azimuth steering angle of 0.75° would be increased, even a larger scene size would be possible also in near range; but at the cost of azimuth ambiguity performance. Here the azimuth resolution is assumed to be constant. Vice versa it would be also possible to improve the resolution while keeping the scene size constant. In the report the possible improvement w.r.t. the scene size is presented. Therefore an analysis concerning the scene size of Sliding Spotlight is shown as well as the impact of the extended steering angle on the azimuth ambiguity ratio.