Unambiguous signal reconstruction for GEO-LEO bistatic SAR with azimuth multichannel

摘要

Spaceborne bistatic multichannel synthetic aperture radar (MC-SAR) system employed inclined geosynchronous Earth orbit (GEO) transmitter and low-Earth-orbit (LEO) receiver can provide fine spatial resolution and a vast area of surveillance, which presents great potentials for future Earth observation. Nevertheless, owing to special geometry and big differences of orbital characteristics, the conventional effective phase centre (EPC) operation for unambiguous SAR signal reconstruction cannot be directly used. To address the issue, starting from geometry model of GEO-LEO bistatic MC-SAR, the new effective positions of the receiving channels are obtained. Then, the time-variant characteristics of residual phase error after the presented EPC processing is analysed. Finally, the method of reconstructing unambiguous SAR signal is presented. Simulation results show the validity of the proposed method, which can efficiently reconstruct the unambiguous signal for GEO-LEO bistatic SAR.