广义S变换和阈值分割联合抗频谱扩展-压缩移频干扰

Spectrum spread and compression shift-frequency jamming suppression by combining generalized S transform and threshold segmentation

根据频谱扩展-压缩(spectrum spread and compression,SSC)移频干扰信号和回波信号时频分布特性的差异,提出一种基于广义S变换和Tsallis交叉熵阈值分割的干扰抑制方法。分析了SSC移频干扰的干扰原理和干扰信号经过解线调后的信号形式,并利用时频聚焦性较好的广义S变换获取接收信号经过解线调后的时频图像,根据时频图像对应的灰度图像,以Tsallis交叉熵最小化作为目标函数,求出灰度图像的最佳分割阈值,并根据分割阈值构建时频滤波器,实现干扰抑制。仿真结果表明:该方法对于SSC移频干扰产生的假目标具有较好的抑制效果,干扰抑制比可达30 dB以上。

According to the time-frequency distribution difference between SSC(spectrum spread and compression) shift-frequency jamming and echo, a jamming suppression method based on generalized S transform and Tsallis cross entropy threshold segmentation was proposed. The jamming principle of SSC shift-frequency jamming was analyzed and the jamming signal model after dechirp processing was constructed. And the generalized S transform, which is of good time-frequency concentration performance, was utilized to acquire the time-frequency image of received signals after dechirp processing. Based on the related gray-scale image of time-frequency image, the minimum Tsallis cross entropy was utilized to obtain the optimal segmentation threshold and the time-frequency filter was constructed according to the segmentation threshold to suppress jamming. The simulation results show that the proposed method is of good jamming suppression performance to the false targets produced by SSC shift-frequency jamming and the jamming suppression ratio can reach more than 30 dB.