一种机载大斜视SAR运动补偿方法

A Novel Method of Motion Compensation for Airborne High Squint Synthetic Aperture Radar

大斜视合成孔径雷达(SAR)成像要求较长的合成孔径,这样载机的不平稳性对其影响较大,如何对大斜视SAR进行运动补偿是实现大斜视成像的关键.本文根据大斜视SAR成像的几何模型,推导出大斜视SAR的瞬时多普勒调频率表达式,并利用从数据中估计得到的多普勒调频率和运动平台的惯导参数来分离和估计运动误差的空间分量,然后利用所得的运动误差对大斜视SAR数据进行包络和相位的运动误差校正.本文所提出的大斜视SAR运动补偿方法能和大斜视SAR成像算法很好地结合,并且仿真和实测数据的成像结果验证了该方法的有效性.

Long synthetic aperture is required in high squint SAR imaging, which is severely influenced by the nonstationarity of airplanes. Therefore, motion compensation is crucial in high squint SAR data processing. A motion compensation approach integrated with the imaging algorithm is proposed. Firstly, the expression of instantaneous Doppler chirp rate is given according to the image geometry model of high squint SAR. Then, the components of motion errors are separated and estimated, using the Doppler chirp rate estimated from measured data and the parameters of inertia navigation system （INS）. After that, the envelope and phase Corrections are performed in high squint SAR data through the obtained motion errors. The effectiveness of the proposed approach can be verified by the imaging results of simulation data and measured data.