Accurate Relative Motion Compensation for Digital Beamforming in Airborne SAR

Abstract

High-resolution wide swath (HRWS) operational modes for spaceborne synthetic aperture radar (SAR) missions are supported by airborne SAR experiments to demonstrate the performance of digital beamforming (DBF) techniques. In practice, the inter-channel motion inconsistencies in airborne DBFSAR must be corrected before azimuth reconstruction occurs. Current motion compensation (MoCo) algorithms can compensate for these inconsistencies but are limited when the dataset is undersampled, as in the case of SAR systems with multiple azimuth phase centers. The innovative solution presented in this paper exploits the fundamentals of multi-channel azimuth reconstruction to relax this limitation and applies channel corrections to account for the differences between the transmitter path and the trajectories of the receivers.