一般构形双基SAR的chirp-z成像方法

Chirp-z Algorithm for General Bistatic SAR

近年来,一般构形双基SAR由于其灵活性等特点,成为SAR的重要研究方向之一,一种典型的一般构形系统就是星-机混合双基SAR。一般空间构形双基SAR由于其具有二维空变性,给成像处理造成困难。针对这一问题,本文分析了基于级数反演法求得的一般构形双基SAR回波二维频率域表达式及其二维空变特性,将此二维频域表达式的相位线性化为目标距离参数和方位位置参数的函数,然后采用两次逆chirp-z处理来解决距离和方位空变问题,由此建立了一般构形双基SAR的chirp-z成像方法。最后通过星-机构形下的仿真验证了此成像方法的有效性。

In last years the interest in general bistatic SAR is increasing and a typical configuration is the space-borne/air-borne hybrid bistatic SAR. Because of the two dimensional variance of general bistatic SAR, it is difficult to focus the echo. In the paper, the spectrum based on series reversion and its two dimensional variance is analyzed, then the chirp-z algorithm is presented to focus the general bistatic SAR echo. The algorithm comprises the two steps of inverse chirp-z transform, with which the range and azimuth variance is processed. Lastly effectivity of the algorithm is confirmed by simulation of hybrid configuration.