Resolution analysis of GEO spaceborne-airborne bistatic SAR based on sliding spotlight mode

For a synthetic aperture radar (SAR) system mounted on a geostationary Earth orbit (GEO) satellite, the track can be curvilinear. Thus, a bistatic SAR system based up on geostationary transmitter and "receive-only" SAR system onboard airplanes, namely GEO spaceborne-airborne bistatic (GEO SA-Bi SAR), is significantly different from the traditional bistatic SAR. This paper mainly studies the resolution characteristic of the sliding spotlight GEO SA-Bi SAR system. Firstly, the common azimuth coverage and coherent accumulated time are theoretically analyzed in detail. Then, based on the gradient method, the accurate two dimensional resolution of a GEO SA-Bi SAR system is analytically calculated. Finally, the simulation data show the correctness and effectiveness of the proposed resolution analysis method.