Meo Spaceborne-Airborne Bisar Imaging Algorithms Based on Azimuth Spatial Variation Compensation

In MEO spaceborne-airborne BiSAR systems, the velocity and slant range histories are very different between the receiving and transmitting platforms. Under the condition of a large slant angle, the echo has serious spatial variability in the azimuth direction, which causes the azimuth defocus. In this paper, the bistatic SAR geometric models of satellite and aircraft are firstly established. After giving the range model, the pattern of spatial variation in azimuth dimension was analyzed. The nonlinear chirp scaling algorithm was used to correct the spatial variation, and the effectiveness of the proposed algorithm is verified by simulation.

1. Introduction

In bistatic synthetic aperture radar (SAR) system, the transmitting antenna and the receiving antenna are located on different platforms. The history of the transmitting slant range and the history of the receiving slant range need to be considered separately, and the characteristics of the echo signal are jointly determined by the transceiver platform. Therefore, compared with single station SAR, bistatic SAR has higher complexity in both system and echo characteristics, and the corresponding imaging algorithm is also more complicated.