SAR Signal Reconstruction from Non-Uniform Displaced Phase Centre Sampling in the Presence of Perturbations

Abstract

The displaced phase centre (DPC) technique enables a wide swath SAR with high azimuth resolution. In classic DPC systems, the pulse repetition frequency (PRF), sensor velocity and antenna length underlie a stringent timing requirement and any deviation will result in a non-uniform sampling of the syn­thetic aperture. This restriction can be overcome by the use of a recon­struction algorithm, which enables a recovery of the unambiguous Doppler spectrum also in case of a non-uniform sampling. This paper ex­plains limitations of the reconstruction imposed by the processing and the impacts on the ambiguity suppression. The potential of the algorithm when applied to DPC systems like TerraSAR-X with its split receive antenna is demon­strated and the benefits re­sulting from the additional receive ap­ertur e regarding swath width and resolution are pointed out. Further on, the impact of ad­ditive and phase noise on the recon­struction and its sensitivity against these perturbations are shown.