一种顺轨干涉SAR时变平地相位去除方法

A Time-Varying Flat Earth Phase Removal Method for Along-Track Interferometric SAR

顺轨干涉合成孔径雷达(ATI-SAR),可以利用2幅SAR图像的干涉相位信息实现对动目标的检测和径向速度的测量。在实际情况下,由于平台和天线相位中心的不稳定,干涉基线的倾角变化会导致时变的交轨基线分量,从而引入平地相位干扰运动目标的检测和测速,需要去除其影响。针对此问题,提出一种基于回波数据的时变平地相位去除方法。该方法通过最小二乘法估计出基线在平地相位中的影响系数,再反演出估计的平地相位值,从而在干涉相位中进行去平地相位,提升了运动目标的检测和测速性能。通过仿真实验验证了理论公式的正确性,并计算了误差。

Along-track interferometric synthetic aperture radar(ATI-SAR)can be used to detect moving targets and measure the radial velocity by using the interferometric phase information of two synthetic aperture radar images. In practice,owing to the instability of the phase center of the platform and the antenna,the change of the interferometric baseline will cause a cross-track baseline component,which will introduce a flat earth phase to interfere with the detection and radial velocity measurement of moving targets and thus the change influence should be removed. In view of this problem,a time-varying flat earth phase removal method is proposed based on the echo data. In this method,the influence coefficient of the baseline in the flat earth phase is estimated through the least square method,and then the estimated flat earth phase value is inversely calculated. These can remove the flat earth phase in the interferometric phase and improve the detection and radial velocity measurement performance of moving targets. Finally, the correctness of the theoretical method is verified through simulation experiment,and the phase error is calculated.