间歇采样转发式干扰的时频域辨识与抑制

摘要

Through partial intercepting and multiple forwarding of a radar transmitting signal, Digital Radio Frequency Memory (DRFM)-based Interrupted Sampling Repeater Jamming (ISRJ) possesses advantages of small size, light weight, and flexibility. Thus, DRFM-ISRJ can be equipped on targets to perform multi-point source main-lobe jamming, posing a serious threat to modern radars. In this study, a time-frequency domain recognition and suppression method was analyzed. First, the expression of pulse compression and Time-Frequency Distribution (TFD) of the jamming signal were deduced. Then, the differences of TFD between target echo and jamming signal were analyzed. On this basis, a jamming recognition program and a time-frequency domain filter to suppress the jamming were proposed. Simulation results show that the recognition rate is better than 90% when the jamming-to-noise ratio is over –3 dB for the received signal. Based on correct recognition, a signal to jamming-and-noise ratio improvement of 18 dB can be achieved using the time-frequency filter.%间歇采样转发式干扰利用数字射频存储器(DRFM)对雷达发射信号进行截获与转发，具有小型化、轻量化和灵活多变的优势，可搭载在目标上形成多点源主瓣干扰，对现代雷达构成了严重威胁。该文对上述干扰的辨识与抑制方法进行了研究。通过推导干扰脉冲压缩与时频分布的解析表达式，分析了目标回波与典型干扰信号的时频特征差异；在此基础上，提出一种时频域干扰辨识方法，并构造时频域滤波器进行干扰抑制。仿真结果表明：在原始信号干噪比大于–3 dB的情况下，算法辨识率可达90%；在此基础上，通过时频域滤波可以对3种典型策略下干扰都进行有效抑制，其峰值信干噪比改善可达18 dB。