基于GPS和改进MapDrift的机载UWB SAR运动补偿

A Motion Compensation Technique Based on GPS and Refined MapDrift for Ultra-Wide Band SAR

传统的基于载机运动传感器的SAR运动补偿对传感器测量精度提出了很高的要求,而基于回波数据的Map- Drift(MD)自聚焦效果对成像场景存在一定的依赖性。本文针对UWB SAR系统的特点,提出了一种结合GPS(Global Position System)粗补偿和改进重叠MD精补偿的机载SAR运动补偿方法。利用GPS的三维位置信息补偿回波时移误差,利用三维速度信息补偿回波相位误差,然后再利用改进重叠MD补偿剩余误差。本文提出的UWB SAR运动补偿方法没有使用高精度的惯导系统,节约了系统成本,降低了补偿系统的实现难度,并减小了MD算法对成像场景的依赖性,有效提升了SAR图像质量。实际UWB SAR数据的处理验证了本文方法的有效性。

Traditional motion compensation for airborne SAR based on hardware requires motion-measurement and navigation system with high-accuracy,which is expensive. Based on the character that attitude information of aircraft is unnecessary for UWB SAR,a new motion compensation method combining real-time GPS and our Refined MapDfift（MD） is proposed in this paper. The GPS information is used to correct most of the motion error of aircraft,that is to say, the GPS position data is used to correct range delay of SAR echo, and the GPS velocity data is used to correct most of phase error. After coarse compensation by GPS, the residual phase error is corrected by our Refined MD. The new method is verified by real UWB-SAR data image and is very attractive for UWB-SAR for its cheapness.