Addressing the Terrain Topography in Distributed SAR Imaging

Distributed multichannel synthetic aperture radar (SAR) imaging is a promising concept for future Earth observation missions. The multichannel concept can mitigate the pulse repetition frequency (PRF) or minimum SAR antenna area constraints inherent to single-channel SAR systems. Thus high azimuth resolution can be maintained, while acquiring wide swathes. This enables global coverage Earth observation with high spatial and temporal resolution. An important step during the multichannel processing for distributed SAR systems is the compensation of the topographic phase. This phase is the result of non-zero cross-track baselines between the antenna phase centers in a constellation or swarm of satellites. The paper in hand investigates different approaches to consider the topography during SAR processing.