单天线SAR动目标的检测和聚焦

单天线SAR运动目标检测系统具有结构简单、算法容易实现等特点,它的运动目标检测性能的完善很有应用意义.首先建立了运动目标SAR回波模型,结合单天线SAR运动目标检测系统,提出了一种基于频域对称扰动的能够对具有方位向速度的运动目标检测的新方法,在详细分析运动目标散焦程度和方位向速度关系的基础上,给出了检测原理以及实现检测的方法.对检测到运动目标的距离门单元,提出了用基于图像域的偏移自聚焦算法估计动目标的调频率,进而完成运动目标在SAR图像上的聚焦成像.并用计算机仿真结果和实测数据验证了算法的有效性.

Detection and focusing of moving targets using a single antenna SAR

The detection of moving targets using a single SAR sensor has several advantages,such as the simple configuration,easy programming and implementation.However,the single-antenna based algorithms still need improvements to satisfy the practical application.An SAR-echo model of moving targets is first established and then,a novel methodology,which is based on the symmetrical disturbing in frequency domain,is presented to detect the moving targets with a azimuth velocity component using a single SAR.After analyzing the relationship between the extent of defocusing induced by the moving targets and azimuth velocities of moving targets,the principle for detection and the method for implementing detection are presented.For each detected moving target in different range cells,the author estimates the frequency modulation rates of moving targets using the excursion autofocus algorithm in the image domain,and then accomplishes the autofocus imaging of moving targets in the SAR image.The effectiveness and efficiency of the proposed method are validated by both the simulated results and real data.