基于参数估计的高分辨率SAR运动目标距离徙动校正方法

A New Approach to Range Cell Migration Correction for Ground Moving Targets in High-resolution SAR System Based on Parameter Estimation

距离徙动校正(RCMC)是机载单天线高分辨率合成孔径雷达(SAR)实现运动目标聚焦成像的关键环节。针对现有方法运算量大、精度低的缺点,该文提出一种结合参数估计分4步完成的RCMC方法。该方法首先通过结合能量均衡法的Hough变换估计距离向速度并校正距离走动,然后以初始方位向调频率校正距离弯曲,再采用Map-drift估计精确的方位向调频率,最后校正残余距离弯曲。与传统方法相比,该方法计算量较小,性能稳定,并能够校正高分辨率下不可忽略的残余距离弯曲。该文给出新方法的数学模型,并通过仿真和实际数据处理验证了该方法的有效性。

Range Cell Migration Correction(RCMC) represents an important advance in moving target imaging in the airborne single antenna high-resolution SAR system. In this paper, we propose a new four-step RCMC approach combined with parameter estimation that overcomes the drawbacks of high computation and low accuracy in high-resolution. First, we use the Hough transform and the energy balancing method to estimate the range velocity and correct the range walk. Next, we perform a range curvature correction in the rangeDoppler domain by using the initial Doppler rate. Thirdly, we accurately estimate the Doppler rate using Mapdrift technology. Finally, we correct the residual range curvature by the accurate Doppler rate. Compared with traditional algorithms, the proposed method requires less computation and is robust in the high-resolution SAR system. In this paper, we present a mathematical model and validate its effectiveness using both simulation and real data.