机载双站SAR运动补偿研究

Motion Compensation for the Airborne Bistatic SAR

与单站SAR相比,双站SAR的几何关系更复杂,运动误差来源更多,因而运动补偿难度更大.本文提出了一种有效的双站SAR运动误差的估计和补偿方法.文中首先根据双站SAR运动误差的几何模型,推导出径向运动误差随距离变化的解析式,接着利用从回波数据估计的多普勒调频率和图像对比度来估计运动参数,最后利用估计的运动参数对数据分别进行径向和沿航向运动补偿.该方法可有效校正收发平台的三维运动误差,并可降低双站SAR系统对惯导的要求.仿真和实测数据的实验结果验证了该方法的有效性.

Compared with the monostatic synthetic aperture radar（ SAR）case, the situation in the bistatic SAR case is more complex.First, the geometry of the bistatic SAR is more complex. Second, both the deviations of the transmitter and the deviations of the receiver will introduce motion errors. These lead to an increased complexity for motion compensation of the bistatic data. This paper presents a method for estimating and compensating the motion errors of the bistatic data. Based on the motion error model of the bistatic SAR, an analytic expression that shows the variation of the motion error in the line of sight（LOS）direction with range is derived. Then,the estimated doppler rate and the image contrast are used to calculate the motion parameters. Finally, the motion compensation are implemented separately in the LOS direction and in the along track direction. By using this method, the three dimentional motion errors of the transmitter and receiver can be compensated effectively, and furthermore, the requirement for the inerial navigation system can be decreased. Results on the simulated data and the real data are provided to show the effectiveness of this method.