基于俯冲模型的SAR成像处理和几何校正

针对高速俯冲状态下斜视SAR(Synthetic Aperture Radar)高分辨率成像处理和几何校正方法进行研究,建立了通用的SAR空间几何模型,在此基础上推导了俯冲状态下的等效斜视距离模型,并给出相应的回波信号数学模型.根据高速俯冲SAR的信号特点,采用Burst工作模式,利用改进的ECS(Extended Chirp Scaling)成像算法进行成像处理,给出了成像处理流程和相位补偿因子表达式.根据距离方程和多普勒定位方程组推导了针对ECS成像算法的几何校正计算公式.计算机仿真结果表明,改进ECS算法能够对俯冲模式SAR进行高分辨率成像处理,并对斜视SAR具有较好的处理能力,提出的几何校正方法能够很好地修正几何失真.

SAR imaging formation and geometric correction method based on diving model

The squint SAR(synthetic aperture radar) high resolution imaging formation and geometric correction method based on the diving model were studied.The general three-dimensional geometric model was founded based on the SAR movement mode.The equivalent squint range model was derived from this general geometric model and the echo signal expression was given based on this range model.According to the signal's characteristic,burst work mode was adopted in diving SAR,and a modified ECS(extended chirp scaling) imaging algorithm was utilized to form high resolution image.The imaging formation flow chart and four ECS phase compensation factors were presented.According to the range equation and Doppler positioning equation,geometric correction calculating expressions corresponding to ECS algorithm were derived.The computer simulation results illuminated that the modified ECS algorithm could be used to form high resolution image for diving model SAR and squint SAR,also geometric distortion could be calibrated with this correction method.