Experimental formation algorithm based on direct wave of BiSAR with the squint transmitter and a fixed receiver

Compared with monostatic SAR, Bistatic SAR has the advantage of abundant information, anti-interception, anti-interference etc. However, few imaging algorithms could be devoted to processing Bistatic asynchronous echo, in view of the difficulties to realize accurate synchronization for focus. Because of the speciality of a stationary receiver configuration in Bistatic SAR, this paper established the basic system geometrical model and signal model at first. Then, based on the geometric character, considering the imaging difficulties of asynchronous echo which caused traditional imaging algorithm invalid, a novel algorithm is raised to focus the echo by using the information existed in the direct wave. Firstly, a quadratic model of the direct wave´s peak phase was introduced to estimate the Doppler rate of echo. Then, the best doppler centroid and squint angle could be searched by applying the rules of picture contrast and optimization, with which the best SRC filter could be assembled and realized the focus of range. Later, through extracting the RCM(Range Migration) and peak phase of the direct wave in range-Doppler domain, we can finish the RCMC(the correction of RCM) and focus in azimuth direction respectively. Finally, corresponding real bistatic data are processed to support it.