3-D Differential SAR Interferometry for Spaceborne SAR Systems with Azimuth Digital Beamforming

Differential shift estimation is an important task for many applications of synthetic aperture radar (SAR). A new generation of spaceborne SAR systems is being designed to use multiple channels in azimuth, which leads to a large available azimuth bandwidth for processing, allowing for an extension of the nominal interferometric SAR processing to retrieve the differential shift between two acquisitions. This contribution estimates the accuracy of the differential shift retrieval in the along-track direction using a 2-look ScanSAR processing for the particular case of the upcoming ROSE-L mission. The derived performance is then validated with a simulation using extended targets, which shows that the azimuth displacement can be retrieved with sufficient accuracy in order to successfully remove the azimuth phase jumps between bursts occurring in the differential interferogram.