Performance analysis and mission design for inclined geosynchronous spaceborne-airborne bistatic SAR

In this paper, a GEO bistatic SAR (GEO-BiSAR) system is studied, where the system consists of a geosynchronous illuminator and an airborne receiver. Compared with a monostatic SAR system, the imaging performance of the GEO-BiSAR is highly dependent on the bistatic observation geometry. Therefore, by properly adjusting the receiver flight parameters, the imaging performance can be improved without adding to the complexity of the GEO transmitter. The spatial resolution characteristics are first analysed based on generalized ambiguity function, where the curved GEO orbit, earth rotation and ellipsoid earth surface are taken into consideration. Then, the system SNR is analysed using the integration equation model. Given the desired spatial resolution and SNR in a specific application, the mission design process can be modeled as a problems of two nonlinear equation systems. Finally, a mission design method based on discrete Newton iteration to determine the receiver flight parameters is proposed to obtain the desired imaging performance. Examples of the mission design process are given to validate the effectiveness of the proposed method.