Randomized stepped frequency radar (RSFR) is very attractive for tasks under complex electromagnetic environment. Due to the synthetic high range resolution in RSFRs, a target usually occupies a series of range cells and is called an extended target . To reconstruct the range-Doppler information in a RSFR, previous studies based on sparse recovery mainly exploit the sparsity of the target scene but do not adequately address the extended-target characteristics, which exist in many practical applications. Block sparsity , which combines the sparsity and the target extension, better characterizes a priori knowledge of the target scene in a wideband RSFR. This paper studies the RSFR range-Doppler reconstruction problem using block sparse recovery. Particularly, we theoretically analyze the block coherence and spectral norm of the observation matrix in RSFR and build a bound on the parameters of the radar, under which the exact recovery of the range-Doppler information is guaranteed. Both simulation and field-experiment results demonstrate the superiority of the block sparse recovery over conventional sparse recovery in RSFRs.

中文翻译：

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利用扩展目标块稀疏性的随机步进频率雷达的理论分析

随机步进频率雷达（RSFR）对于复杂电磁环境下的任务非常有吸引力。由于RSFR中具有合成的高范围分辨率，因此目标通常会占据一系列的距离单元，并称为扩展目标 。为了在RSFR中重建距离多普勒信息，先前基于稀疏恢复的研究主要利用目标场景的稀疏性，但没有充分解决扩展目标特性，在许多实际应用中都存在这种特性。块稀疏 结合了稀疏性和目标扩展，可以更好地表征宽带RSFR中目标场景的先验知识。本文研究了基于块稀疏恢复的RSFR距离多普勒重建问题。特别是，我们从理论上分析了RSFR中观测矩阵的块相干性和频谱范数，并建立了雷达参数的界限，在此范围内，可以保证距离多普勒信息的准确恢复。仿真结果和现场实验结果均表明，在RSFR中，块稀疏恢复优于常规稀疏恢复。