高速平台下动目标高分辨成像方法研究

Research on moving target SAR imaging algorithm within high-speed platform

摘要:

高速平台对地面强散射移动目标或者海面舰船目标进行合成孔径雷达成像（SAR）时，存在两方面问题：一是传统SAR匀速直线模型已不适应高速平台自身高动态运动特征；二是目标的非合作运动一方面会引起图像散焦，另一方面动目标在地距图中的位置会产生较大偏移。针对这两个问题，首先在匀加速度模型频域相位滤波算法下，推导出了精确的斜地投影关系以及近似的反投影关系，同时给出了基于惯性组合导航（INS）的平台运动补偿方法，最后结合自聚焦技术，完成对舰船目标的聚焦并得到以目标为图像中心的地距图。

Abstract:

Two problems exist in which synthetic aperture radar imaging (SAR) for ground -moving targets or ships with strong scattering within high speed platform: one is that the incompatibility between the traditional uniform velocity model in SAR and the high-dynamic characteristic of high speed platform, the other is that defocusing image results in the unpredictability of motion of moving target. Firstly, frequency filtering algorithm used in uniform acceleration model is introduced, an accurate mapping function and an approximately inverse mapping function used in projection is proposed. Then a method of motion compensation based on inertial integrated navigation system(INS) is proposed, which is applied to the acceleration model. At last, PGA autofocus algorithm is adopted to focus the blurring image in Doppler domain. As a result, ground distance map with the target as the center of the image is obtained.