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线性调频步进信号在简化雷达系统设计的同时,也存在对高速运动目标易出现Doppler模糊的问题,因此研究如何提高其等效的重复频率具有重要意义.由于ISAR目标的后向散射场具有较强的稀疏性,即大部分能量仅由少数散射中心贡献,所以本文基于稀疏信号表示理论,通过对目标回波模型的分析,提出了一种基于稀疏步进频率信号的逆合成孔径雷达成像方法.该方法通过随机地选择线性调频步进信号的部分子脉冲进行发射,然后使用稀疏信号分解的方法对目标图像进行重建以得到目标的二维高分辨图像.该方法以计算资源为代价,能够有效地去除方位Doppler模糊,同时还能够压低旁瓣并得到超分辨的图像.仿真和实测数据处理结果验证了本文方法的有效性.
The linear FM step-by-step signal simplifies the design of radar system and also has the problem of easy Doppler ambiguity for high-speed moving targets. Therefore, it is of great significance to study how to improve its equivalent repetition frequency.As the backscattering field of ISAR targets has more Strong sparsity, that is, most of the energy is only contributed by a few scattering centers. In this paper, based on the sparse signal representation theory, an inverse synthetic aperture radar imaging method based on sparse stepping frequency signal is proposed by analyzing the target echo model In this method, the target image is reconstructed by sparse signal decomposition by randomly selecting some sub-pulses of the chirp signal to obtain a two-dimensional high-resolution image of the target. The method can calculate the resource, Which effectively removes the directional Doppler blur and lowers the side lobes and obtains super-resolution images.The simulation and experimental data processing results verify the effectiveness of the proposed method.