Local DEM Compensation for Along-Track SAR Formations

Along-track formations of small satellites are of great interest for future Synthetic Aperture Radar (SAR) systems since they can image at high resolution over wide swaths. Each sensor operates with reduced pulse-repetition-frequency (PRF), which causes significant azimuth ambiguities. However, these ambiguities can be removed by a well-known multichannel recombination that is effective only if the cross-track (XT) baseline between sensors is kept negligible. This work proposes a post-processing approach to mitigate the residual ambiguities caused by small XT baselines based on the knowledge of the scene's Digital Elevation Model (DEM). The method has been validated with simulated data, considering a realistic distributed scene.