中文摘要：

双基合成孔径雷达（Synthetic aperture radar,SAR）极坐标格式算法（Polar format algorithm,PFA）是基于平面波前假设建立的,在聚焦过程中会引入波前弯曲误差,使聚焦图像出现空变几何失真和散焦现象.因此,实际应用双基PFA时其有效成像场景的大小通常受到一定限制.本文提出了一种基于数字聚束技术的双基PFA波前弯曲误差补偿新方法.该方法首先利用数字聚束预滤波处理将原始的宽波束划分成多个对应不同子场景的窄波束,然后依次对窄波束数据进行补偿和成像,最后再通过子场景拼接恢复全场景图像.理论和仿真结果表明该方法能够有效地补偿波前弯曲误差,扩大双基PFA的有效场景聚焦范围.

英文摘要：

The polar format algorithm（PFA） for bistatic SAR imaging is based on the planar wavefront assumption which introduces wavefront curvature effect in the focusing process.There is space-variant geometry distortion and defocusing effect in the focused image via bistatic PFA.Hence,the focused scene size using bistatic PFA is usually restricted.A new method is proposed to solve the problem of wavefront curvature compensation using the digital spotlighting technology.Firstly,the digital spotlighting is preprocessed to divide the original wide beam into several narrow beam phase history data,each of which corresponds to different small image patch.And then each narrow beam is compensated and imaged.Finally all these focused image patches are mosaiced together to get a full scene image.Theory and simulation results show that the method can effectively compensate the wavefront curvature effect and enlarge the focused scene size for bistatic PFA.