UWB SAR图像的非均匀分段PGA算法

在超宽带合成孔径雷达(UWB SAR)成像过程中,由于载机偏航所导致的相位误差具有严重的距离向空变性,因此需要沿距离向分段应用相位梯度自聚焦(PGA)算法以改善PGA算法的聚焦性能.本文分析了载机空间偏航位置与相位误差空变特性之间的关系,提出了图像非均匀分段PGA(NUSPGA)算法,并从理论上对算法进行了推导.文中还提出了参考点对齐法以校正分段聚焦后子图像间的平移失真问题.最后由实测数据验证了本文所提算法的有效性.

A Non-Uniform Segmentation PGA Algorithm for UWB SAR Image

In the process of Ultra-Wideband Synthetic Aperture Radar (UWB SAR) imaging,the phase error induced by the plat- form off-track motion is seriously range dependent. So the images are usually segmented along range direction and the Phase Gradient Autofocus (PGA) algorithm is applied to each sub-image to improve the focusing performance. In this paper,we first analyzed the rela- tionship between the platform off-track motion and the range-dependent characteristic of the phase error,and a non-uniform segmentation PGA (NUSPGA) algorithm is proposed on the basis of theoretical deduction. This paper also proposed the reference scatterer coregistra- tion method to remove the shift distortion among the focused sub-images after image-segmented autofocus. At last,the raw data verify the effectiveness of the methods proposed in this paper.