基于数字聚束技术的双基SAR PFA波前弯曲补偿算法

双基合成孔径雷达（Synthetic aperture radar, SAR）极坐标格式算法（Polar format a lgorithm, 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。

Bistatic SAR PFA Wavefront Curvature Compensation Based on Digital Spotlighting Technology

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