跳频信号盲检测的时频语义对消方法

复杂电磁环境下精准检测跳频信号是实施跳频信号侦查的先决条件。针对复杂干扰下跳频信号难以检测的问题，本文提出一种名为时频语义对消的方法。该方法设计了一种具有自注意力和图注意力机制的暹罗嵌套UNet，并根据该网络提取包含跳频信号、干扰信号和噪声的时频图语义信息。将得到的结果与不包含跳频信号时频图的语义信息相消就可以得到仅包含跳频信号的时频图，实现对跳频信号的检测。仿真结果表明所提方法可以在复杂干扰下实现对跳频信号的参数估计与盲检测，在信噪比高于-5 dB和信干比高于0 dB时，虚警概率与漏警概率低于1‰。在信号时频范围检测中，对比实验表明语义对消检测方法比语义分割检测方法交并比分数提升0.31，消融实验表明注意力模块对交并比分数提升为0.022。同时分析了所提网络的复杂度，结果表明该方案具有较小的参数量以及较快的处理速度，可以运用于跳频信号的实际检测当中。 

Time-frequency Semantic Cancellation Method for Frequency Hopping Signal Blind Detection

? ?Frequency hopping signal detection in a complex electromagnetic environment is the first step for frequency hopping signal reconnaissance. This paper proposed a method called time-frequency semantic cancellation to detect signals under complex interference. This method designed a Siamese nested UNet with self-attention and graph attention mechanism. With this network， the semantic information of spectrogram containing frequency hopping signal， interference signal and noise was extracted， and then eliminated it with semantic information of the spectrogram without frequency hopping signal. Thus， the spectrogram only containing frequency hopping signal was obtained， so as to realize the signal detection. The simulation results showed that the proposed method could realize parameter estimation and blind detection of frequency hopping signals under complex interference. When signal-to-noise ratio was higher than -5 dB and signal-to-interference ratio was higher than 0 dB， the false alarm probability and missed alarm probability were less than 1‰. In time-frequency range detection， the experiment showed that the semantic cancellation detection method increased the Intersection over Union score by 0.31 compared with the semantic detection method， and the ablation experiment shows that the attention module increased the Intersection over Union score by 0.022. At the same time， the complexity of the proposed network was analyzed. The results show that this scheme has a small number of parameters and a fast-processing speed， which can be applied to the actual detection of frequency hopping signals.