基于坐标变换的合成孔径雷达高精度成像算法

High precision imaging algorithm for synthetic aperture radar based on coordinate conversion

针对当前合成孔径雷达成像算法处理低频大斜视角数据存在的散焦和运算量大问题,提出了一种新的高精度大斜视合成孔径雷达成像算法.算法首先把数据录取坐标系数据变换到零多普勒坐标系数据,然后在零多普勒坐标系中采用距离时域非均匀傅里叶变换去除距离、方位的耦合,进而得到聚焦良好的合成孔径雷达图像.算法运算量与距离多普勒算法在一个量级,具有较高的成像效率.仿真结果表明算法在低频大斜视角下能很好地聚焦,从而验证了算法的正确性.

New high precision imaging algorithm for low-frequency high squint synthetic aperture ra- dar （SAR） is proposed in this paper for existed SAR algorithms with the problems of defocusing and heavy calculation. The proposed algorithm transforms the SAR data from acquisition Doppler geometry to zero Doppler geometry and then operates ununiform fast Fourier transform （FFT） in range-time domain data to decoupling between range and azimuth. The SAR images focus well after above operations. The computa- tional burden of the proposed algorithm is in the same level as range Doppler（RD） algorithm and has high imaging efficiency. Simulations verify that the proposed algorithm focus well in low frequency high squint SAR. The results demonstrate the correctness of the proposed algorithm.