The TerraSAR-X Staring Spotlight Mode Concept

The paper investigates the possibility to enhance the TerraSAR-X (TSX) azimuth resolution by means of staring spotlight imaging in combination with an extended azimuth pattern steering. The current TSX spotlight modes are briefly reviewed, and the azimuth steering limitations are discussed. Based on a realistic TSX azimuth pattern simulation and performance estimation using a Kepler orbit and the WGS84 reference ellipsoid, the key performance parameters are estimated for an increasing azimuth pattern steering angle span. The azimuth ambiguity performance is identified to be the driving performance parameter. Experimental TSX staring spotlight high-resolution images are presented. They demonstrate and verify the envisaged performance estimation. The paper concludes with a concept for a high-resolution TSX staring spotlight mode that serves as baseline for the upcoming operational implementation.