Using a Large Space-Variant Beamformer for Multistatic SAR Imaging

Abstract

Multistatic synthetic aperture radar (SAR) imaging is a promising candidate for future Earth observation missions. On the one hand, the multichannel concept enables high azimuth resolution while acquiring wide swathes. On the other hand, the use of many small satellites provides the benefits of cost efficient mass manufacturing and graceful degradation which reduces the effort for redundancy on the single platforms. One of the key challenges is the processing of the SAR data of many distributed channels to a single high-resolution image. Compared to single platform multichannel systems, the phase centers are no longer aligned in azimuth direction, but baselines in cross-track and line-of-sight direction are inevitable. Additionally, the sampling in along-track is also a function of the formation and the used pulse repetition frequency (PRF). Several approaches for the processing have been investigated in literature. The paper in hand investigates a beamforming approach and discusses its benefits and limitations.