一种基于幅度和相位迭代重建的四维合成孔径雷达成像方法

摘要

4维合成孔径雷达获取的观测数据在基线-时间平面非均匀分布。若采用传统成像方法来获取目标散射体的高度-速率维像，则因强副瓣存在，成像效果不理想。当信号具有稀疏性时，压缩感知技术能够利用少量的信号投影值就可实现信号的准确或近似重构。然而标准的压缩感知成像方法是针对实数据进行处理，4维合成孔径雷达成像处理的数据为复数据。因此该文提出了一种基于幅度和相位迭代重建的4维合成孔径雷达成像方法。将4维合成孔径雷达高度-速率成像问题转化为目标复散射系数的幅度和相位联合重建问题，通过在成像过程中引入相位信息来改善成像质量。仿真结果验证了该算法的有效性。%Observation data obtained from the Four-Dimensional (4D) Synthetic Aperture Radar (SAR) system is sparse and non-uniform in the baseline-time plane. Hence, the imaging results acquired by traditional Fourier-based methods are limited by high side lobes. Compressive Sensing (CS) is a recently proposed technique that allows for the recovery of an unknown sparse signal with overwhelming probability from very limited samples. However, the standard CS framework has been developed for real-valued signals, and the imaging process for 4D synthetic aperture radar deals with complex-valued data. In this study, we propose a new 4D synthetic aperture radar imaging algorithm based on an iterative reconstruction of magnitude and phase, which transforms the height-velocity imaging problem of 4D synthetic aperture radar into a joint reconstruction problem of the magnitude and phase of the complex-valued scatter coefficient. Using the phase information in the algorithm, the image quality is improved. Simulation results confirm the effectiveness of the proposed method.