基于子孔径相位误差拼接的相位梯度自聚焦算法

随着雷达技术的发展,合成孔径雷达的成像精度也得到了大幅提升,与之相匹配的,也需要能更精确地进行运动补偿的算法.由于惯导精度无法满足需求,如果仅使用惯导数据对运动误差进行补偿,补偿的结果中含有残余的距离单元徙动,这会损失图像的精度.本文首先分析了残余的距离单元徙动对快速分解后向投影成像算法和相位梯度自聚焦算法的影响,再将...

A Phase Gradient Autofocus Algorithm Based on Subaperture Phase Error Stitching

With the development of radar technology,the imaging accuracy of synthetic aperture radar(SAR)has been greatly improved,which requires algorithms that can perform motion compensation more accurately.Accuracy of inertial navigation data is not enough for current SAR imaging.If motion compensation is performed by using only inertial navigation data,the imaging accuracy will be degraded because of residual range cell migration.In this paper,the impact of residual range cell migration on fast factorized back-projection(FFBP)imaging algorithm and phase gradient autofocus(PGA)algorithm is analyzed at first.And then the PGA algorithm for spotlight SAR phase error compensation is optimized,resulting in a PGA algorithm based on subaperture phase error stitching.The proposed PGA algorithm makes it possible to compensate for residual range cell migration,which can also be applied to the strip SAR.At last,the measured data of a Ku-band radar prove the effectiveness of the proposed algorithm.