基于稀疏采样的空间碎片群目标成像方法

Space Group Debris Imaging Based on Sparse Sample

低重频、短数据条件下的雷达成像是比较困难的,同时,星载平台观测的碎片目标多以群目标形式出现。针对窄带条件下的空间碎片群目标成像问题,该文提出了一种基于稀疏重构的空间碎片群目标成像方法。由于空间碎片通常存在高速自旋现象,且碎片之间因质量、密度等物理差异存在明显的转速差,利用观测时间内碎片群的多周期观测数据与转速差异性,结合回波的自相关特性,能有效实现碎片群的转速检测。由于碎片在空域具有强稀疏特性,结合碎片转速,利用观测矩阵抽取数据,可以实现等效插值操作,并且将稀疏重构得到的数据进行重排,即可得到各个目标的像。抽取操作能够一定程度地抑制其他碎片的回波能量,并解决在低重频条件下的多普勒模糊问题。理论分析证明了该文所提方法的有效性,仿真实验表明,该文所提方法能够在低重频条件下实现对碎片群目标的分别成像。

Space group debris imaging is difficult with sparse data in low Pulse Repetition Frequency（PRF）spaceborne radar.To solve this problem in the narrow band system,we propose a method for space group debris imaging based on sparse samples.Due to the diversity of mass,density,and other factors,space group debris typically rotates at a high speed in different ways.We can obtain angular velocity through the autocorrelation function based on the diversity in the angular velocity.The scattering field usually presents strong sparsity,so we can utilize the corresponding measurement matrix to extract the data of different debris and then combine it using the sparse method to reconstruct the image.Furthermore,we can solve the Doppler ambiguity with the measurement matrix in low PRF systems and suppress some energy of other debris.Theoretical analysis confirms the validity of this methodology.Our simulation results demonstrate that the proposed method can achieve high-resolution Inverse Synthetic Aperture Radar（ISAR） images of space group debris in low PRF systems.