Unambiguous SAR Signal Reconstruction From Nonuniform Displaced Phase Center Sampling

TLDR

The displaced phase center (DPC) technique allows wide‑swath SAR with high azimuth resolution, but requires a precise PRF so that the carrier moves half an antenna length between pulses; otherwise the synthetic aperture is sampled nonuniformly. This letter derives an innovative reconstruction algorithm that enables unambiguous SAR signal reconstruction from nonuniform synthetic‑aperture sampling. The algorithm compensates for the nonuniform sampling induced by PRF deviations through a novel reconstruction method. The method shows promise for multistatic satellite constellations and dual‑receive‑antenna modes in Radarsat‑2 and TerraSAR‑X.

Abstract

The displaced phase center (DPC) technique will enable a wide-swath synthetic aperture radar (SAR) with high azimuth resolution. In a classic DPC system, the pulse repetition frequency (PRF) has to be chosen such that the SAR carrier moves just one half of its antenna length between subsequent radar pulses. Any deviation from this PRF will result in a nonuniform sampling of the synthetic aperture. This letter derives an innovative reconstruction algorithm and shows that an unambiguous reconstruction of a SAR signal is possible for nonuniform sampling of the synthetic aperture. This algorithm will also have great potential for multistatic satellite constellations as well as the dual receive antenna mode in Radarsat 2 and TerraSAR-X.