联合时频重排和双正交傅里叶变换对抗频谱弥散干扰

Jointing Time-frequency Reassignment and Biorthogonal Fourier Transform Countering Smeared Spectrum Jamming

频谱弥散(SMSP)干扰由多个LFM子信号时域拼接而成,利用信号处理工具重构干扰信号,需要进行多次滤波。针对该问题,分析了SMSP干扰时频特征,在此基础上,提出联合时频重排和双正交傅里叶变换SMSP干扰抑制算法。首先,对回波时频重排矩阵进行Radon变换,估计干扰子信号个数。其次,根据估计的子信号个数设计参考信号,将回波中的SMSP干扰调制成一个LFM信号。然后,对调制后回波进行BFT峰值滤波处理,解调重构干扰信号。最后,将回波减去重构信号实现干扰抑制。仿真结果表明,所提算法无需估计全部干扰参数,仅需一次峰值滤波解调处理即可准确重构干扰信号,对消后回波中的SMSP干扰得到有效抑制。

SMeared SPectrum(SMSP)jamming is composed of multiple LFM sub-signals in time domain.In order to reconstruct the SMSP jamming with signal processing tools,multiple-filtering is inevitable.For this problem,this paper analyzes the time-frequency characteristic of SMSP jamming.On this basis,a jamming suppression algorithm jointing Time-Frequency Reassignment(TFR)and Biorthogonal Fourier Transform(BFT)is proposed.Firstly,the number of jamming sub-signals is estimated according to the Radon transform result of echo TFR matrix.Secondly,based on sub-signals number,the reference signal is designed to modulate jamming signal into a LFM signal.Then,the jamming signal is reconstructed by BFT peak filtering and demodulation.Finally,by subtracting reconstructed signal from echo,the purpose of jamming suppression is realized.The simulation results show that the proposed algorithm do not need to estimate all the jamming parameters and the jamming signal can be reconstructed accurately by once filtering and demodulation process.After cancellation,the SMSP jamming in echo is effectively suppressed.