基于高阶谱净化的水声目标宽带调制信号检测

Detection on Broad-band Modulated Signal of Underwater Acoustic Object Based on High-order Spectrum Purification

针对水声目标解调谱轴频提取中低信噪比和低频信号干扰严重的问题,给出了一种检测水声目标辐射噪声宽带调制信号的方法。首先利用希尔波特变换解调出信号包络,进而计算出解调谱;根据螺旋桨桨叶旋转产生的调制线谱存在明显的谐波关系,利用高阶累计量对角切片对解调谱进行净化;根据线谱波形特征进行线谱检测识别得到比较干净的线谱成分。通过实际舰船噪声检验分析,该调制信号检测方法能够较好的检测出水下目标辐射噪声中调制线谱的基频以及谐波成分。

To solve the problems of low SNR and severe interference in low frequency signal in the estimation of propeller shall rate, a method of detecting line-spectrum in DEMON （Detection of Envelope Modulation on Noise） spectra is given in this paper. By means of Hilbert transform, the author obtains the signal envelope, and then calculates the demodulation spectrum. The cleaned harmonics in the modulation line-spectrum has been brought out because of the propeller blade＇s running, and the DEMON spectrum is puritied by the characteristic of the higher-order cumulating diagonal slice. The result of real vessel noise data experiment shows that the method and algorithm proposed are effective and feasible. And it can get hold of the basic frequency and its harmonics.