Geosynchronous spaceborne-airborne bistatic SAR: Potentials and prospects

Geosynchronous synthetic aperture radar (GEOSAR) illuminates a vast ground area with short revisit cycle, which shows huge potential for bistatic observation. In this paper, the concept and advantages of GEO spaceborne-airborne bistatic SAR (GEO-BiSAR) are investigated. The system consists of an inclined geosynchronous illuminator and an airborne receiver. The observation geometry is first put forward. The spatial resolution and radiometric characteristics and performances are then analysed. The advantages are specified compared with a monostatic GEO-SAR system. It is proven that the bistatic configuration can provide finer spatial resolution and higher SNR with less system complexity and power consumption. The imaging performance can be cost-effectively improved and optimized by flexibly adjusting the motion parameters of the airborne receiver. The proposed GEO-BiSAR system provides an exciting alternative for current GEO-SAR missions.