一种新的圆迹SAR快速后向投影算法

A New Algorithm of Fast Back Projection in Circular SAR

后向投影算法能够解决圆迹合成孔径雷达成像中的距离向和方位向耦合问题,是一种精确的时域成像算法,但较大的计算量阻碍了其在工程实际中的应用。基于后向投影算法的成像原理,提出了一种快速后向投影成像算法。快速后向投影算法将目标区域的成像网格点投影在目标区域中心与雷达位置的连线所表示的一维距离上,其后将一维距离对应到各方位向经距离压缩后的数据上,并在各个方位向相干叠加,得到目标区域成像。通过定量分析和对比快速后向投影算法和传统后向投影算法的计算量,快速后向投影算法的运算速度得到大幅度提高。通过仿真分析,验证了该算法的有效性。

The back projection algorithm is a precise time domain algorithm which could solve the problem of coupling of range and azimuth directions in circular synthetic aperture radar.But the huge computation prevents its application in engineering practice.A new kind of fast back projection algorithm based on the imaging theory of the back projection way is put forward.The new algorithm can obtain the image of target area by projecting the imaging grid of target area on the one dimensional distance which is the line between the center of target area and the position of radar and then projecting the one dimensional line on the data after range compression in every azimuth direction.The imaging is gotten when the values of imaging grid after projection in all azimuth directions are added together.The result shows that the speed of operation is greatly improved by the quantitative analysis of the computational variance between the traditional algorithm and the new back projection algorithm and the effectiveness of the algorithm speed is verified by simulation analysis.