浅海波导中简正波干涉特征频率增强

Enhancement of characteristic frequency of coherent normal mode pairs in shallow water waveguides

针对浅海波导中水平线列阵接收的低频宽带低信噪比信号,提出了一种利用多拍信号相干累加来提高干涉简正波特征频谱信噪比的方法。这种方法主要针对未知距离和声源形式的运动声源,对不同时刻(或接收距离)处阵列输出信号进行warping变换,根据干涉简正波的特征频率不变性,通过搜索距离与径向速度的比值来对齐未知距离下warping变换后的谱峰频率,进而通过相干累加来增强信号干涉简正波的特征频率。仿真和海上实验数据分析均验证了方法的性能。

Aiming at the low-frequency and low signal-to-noise ratio signals received by a horizontal line array in shallow-water waveguides,an approach to enhance the signal-to-noise ratio of characteristic spectra of the coherent normal mode pairs is proposed based on coherent accumulation of multiple snapshot signals.For a moving sound source without knowledge of range and waveform,warping transform is performed on the array output signals at different time or receiving ranges.According to the characteristic frequency invariability of the coherent normal modes,the peak frequency after warping transform at unknown range is aligned by searching the ratio of range to radial velocity.And then,coherent accumulation is used to enhance the characteristic frequency of the coherent normal mode pairs.The simulation and the analysis of marine experimental data verify the performance of the approach.