结合方位空变补偿的大斜视SAR误差估计方法

大斜视合成孔径雷达(SAR)成像中距离方位信号的强耦合性给成像处理带来困难,现有SAR成像算法常采用线性走动校正来降低其耦合性,该处理方法在一定程度上简化了后续成像处理的同时也带来方位相位空变问题。现有成像算法对方位相位空变校正均假设在无运动误差的理想条件下,未能考虑方位空变相位对运动误差估计的影响。针对该问题,文中首先从多角度详细分析了线性走动校正以及方位空变相位对方位运动误差估计的影响,提出一种结合方位空变相位补偿的大斜视SAR成像运动误差估计方法,保障了后续的成像处理、提升了整体成像质量。仿真和实测数据处理验证了该算法的有效性。

A Motion-error Estimation Method for Hight Squint SAR Combined with Azimuth-variant Phase Compensation

For high squint synthetic aperture radar (SAR) data processing, it is difficult to deal with the greatly coupled signal between range and azimuth. For mitigating this coupling and simplifying the following processing, the linear range walk correction(LRWC) is often introduced with sacrifice of the limitation of focus depth. In the current SAR imaging algorithms, the azimuth-variant phase compensation methods are established without consideration of motion errors and ignore the effects of azimuth-variant phase on motion-error estimation slightly. For this issue, a detail analysis on the effects of the LRWC and azimuth-variant phase is given, and then a motion-error estimation method combined with azimuth-variant phase compensation is proposed in this paper. The proposed method ensures the following data processing and improves the imaging quality of the final focusing. Both the simulation results and real data processing validate the effectiveness of the proposed method.