利用拖船辐射噪声的深海声学参数近场匹配场反演方法

针对深海声学参数难以通过远距离合作声源反演获取的问题,提出了利用拖船低频噪声近场匹配场反演方法。首先,利用聚焦波束形成计算拖曳阵接收拖船噪声的方向性,获得传播路径特征;然后,构建多参数反演模型,由波数积分声传播模型计算拷贝场,采用遗传算法对多频匹配场目标函数进行反演。同时,采用蒙特卡罗方法分析参数后验概率密度。仿真与试验结果表明:深海环境中拖曳阵接收拖船噪声主要来自海底反射路径,利用该特性反演得到海水深度、噪声源距离、阵列深度、沉积层厚度等参数,多频联合反演可以提高沉积层厚度等参数反演准确性。宽带匹配场处理表明,利用反演最优参数模型能准确给出拖船噪声源的空间位置。 

Near-field matched-field inversion using tow-ship noise in deep water

The geoacoustic parameters can hardly be inverted using far-field controlled-source due to the sound propagation in deep water. To aim at this problem, we developed a near-field Matched-Field Inversion (MFI) method using tow-ship noise data in deep water. First, the multipath behaviour of tow-ship noise acquired via towed array was investigated by performing near-field beamforming. Then, the multi-parameter geoacoustic model was established to calculate replica fields using wavenumber integration approach, and multi-frequency MFI was performed using genetic algorithm. Finally, The Posterior Probability Density (PPD) of the parameters was investigated using Monte Carlo method. The tow-ship noise near-field MFI method was verified by simulations and real trial data processing. The results indicated that tow-ship noise mainly came from the seabed reflection path in deep water, and multiple parameters such as water depth, source range, array depth, and sediment thickness were inverted by the proposed method. And a more accurate result of sediment thickness and other parameters was achieved by performing multi-frequency MFI. The wideband Matched Field Processing (MFP) ambiguity surface based on the inverted acoustic model could give the precise location of tow-ship radiated noise source.