基于二维稀疏特性的空间目标高分辨ISAR成像方法

针对空间三轴稳定目标成像问题，提出了一种基于目标稀疏特性的空间目标高分辨ISAR成像方法.该方法利用精轨数据构建了保相波形延时字典，实现了距离维高分辨和平动补偿；利用旋转矢量分析方法计算了三轴稳定空间目标有效积累转角，结合高分辨距离像的稀疏特性，给出了一种适用于越距离单元徙动的方位维稀疏字典构建方法.仿真结果表明，构建的稀疏匹配字典正确反映了目标的姿态变化特性，解决了越距离单元徙动问题，结合距离维相干抑制显著提高了空间目标二维ISAR像的分辨能力. 

High Resolution ISAR Imaging of Space Target Based on Two-Dimensional Sparse Characteristics

Aiming at the ISAR imaging problem of three-axis stabilized space target,a two dimensional high resolution ISAR imaging method was proposed based on sparse characteristics and orbit model.Firstly,a phase-stable wave shape dictionary was developed with target orbital data to realize high range resolution and motion compensation. Then, considering the translational motion and attitude stabilization of target running on orbit, the effective accumulation angle of three-axis stabilized space target was calculated with target rotation vector analysis.According to the sparse characteristics of high range resolution profile (HRRP),the cross-range matching dictionary size was decided effectively, and a dictionary structure was proposed to adapt to the migration through resolution cell (MTRC).The simulation results show that the sparse matching dictionary can correctly reflect the attitude change of space target,solve the MTRC problem of scatters,and significantly improve the two-dimensional resolution of the space target ISAR image.