Towards the Retrieval of 2-D Vessel Velocities with Single-Platform Spaceborne SAR: Experimental results with the TerraSAR-X 2-looks TOPS Mode

In this contribution, we propose the use of two-looks Synthetic Aperture Radar data to retrieve azimuth velocities of moving targets with a single platform. The established technique to retrieve velocities of moving targets is Along-track Interferometry (ATI), which provides a measurement of the velocity in the radar line of sight direction by employing two or more phase centers separated in the along-track direction. The use of two-looks data allows to observe targets at two different instants of time, enabling the retrieval of the target velocity in the azimuth direction. We introduce the experimental two-looks Terrain Observation by Progressive Scans (TOPS) mode, presenting the performance that can be achieved with the TerraSAR-X system. Moreover, we present results with real data acquired with TerraSAR-X over coastal areas to retrieve velocities of vessels. It is foreseen to include in the final version of the paper a validation of the results with Automatic Identification System (AIS) data (ground truth)