Multistatic radar system (MSRS) is considered an effective scheme to suppress mainlobe jamming, since it has higher spatial resolution enabling jamming cancellation from the spatial domain. To develop electronic countermeasures against MSRS, a low complexity random array subset selection (RASS) jamming method is proposed in this paper. In the RASS jammer, elements of the array antenna are activated randomly, leading to stable mainlobe and random sidelobes, which is different from the traditional jammer that applies the complete antenna array enjoying constant mainlobe and sidelobes. We study the autocorrelation matrix of RASS jamming signals received by radars, and derive its rank, revealing that the rank of jamming subspace is increased thus severely degrading the performance of jamming cancellation. Moreover, we calculate the output jamming to signal-and-noise ratio (JSNR) after the subspace-based jamming suppression methods used in MSRS with the proposed jamming method, which demonstrates that the rank increasing property invalidates such suppression methods. Both simulation and experiment results verify our analytical deduction and exhibit the improved countermeasure performance of our proposed RASS jamming method compared to the traditional jammers.

多基地雷达系统（MSRS）被认为是抑制主瓣干扰的有效方案，因为它具有更高的空间分辨率，可以消除空间域的干扰。为了开发针对MSRS的电子对策，本文提出了一种低复杂度的随机数组子集选择（RASS）干扰方法。在RASS干扰器中，阵列天线的元件被随机激活，从而产生稳定的主瓣和随机副瓣，这与传统的干扰器不同，传统的干扰器应用了具有恒定主瓣和副瓣的完整天线阵列。我们研究了雷达接收到的RASS干扰信号的自相关矩阵，并推导了其秩，表明干扰子空间的秩增加了，从而严重降低了干扰消除的性能。而且，我们用提出的干扰方法计算了MSRS中基于子空间的干扰抑制方法后，计算出输出干扰信噪比（JSNR），这证明了等级增加特性使这种抑制方法无效。仿真和实验结果均证实了我们的分析推论，并显示了与传统干扰器相比，我们提出的RASS干扰方法具有改进的对策性能。