Research On Seabed Geoacoustic Inversion Based On Opportunity Sound Source

The performance of underwater acoustic detection and communication depends on the knowledge of ocean environment,and the characteristics of the seabed geoacoustic directly affect the sound propagation.Geoacoustic parameter inversion is one of the effective methods to obtain ocean environmental parameters.Geoacoustic inversion using opportunity sound source such as ship ra-diated noise is of great significance in ecological protection and military applications.In this paper,using the dispersion curve method and the matched field method,Geoacoustic parameter inversion of opportunity sound source in shallow sea environments is studied.Using the dispersion characteristics of broadband signals propagating in a shallow ocean waveg-uide environment,geoacoustic parameter inversion using dispersion curves is proposed.Trans-forming the dispersion curves from the time-frequency domain to the wavenumber-frequency do-main improves the performance of the dispersion characteristics.Substituting the objective function of structural similarity for the mask function improves the robustness of the inversion of water depth parameters.Combining the simplified point source model of ship radiated noise with matched field inver-sion,this paper proposes an inversion framework for seabed geoacoustic parameters of opportunity sound source.The effects of receiving array type,signal-to-noise ratio and objective function on the inversion performance are studied respectively.In the iterative process of global optimization using the differential evolution algorithm,the variation strategy that combines the information of the previous generation and the parent generation has the best inversion performance.In addition,combining cooperative sound source and opportunity sound source to invert geoacoustic parameter can complement and improve the effectiveness and robustness of geoacoustic parameter inversion.The inversion method of geoacoustic parameters based on the dispersion curves is verified by the 2017 SBCEX data.The 2016 sea trial data of Liuheng Island in Zhoushan verified the effectiveness of geoacoustic parameter inversion for opportunity sound source.The 2019 sea trial data acquisition system of Xiushan Island in Zhoushan was designed,and the predicted transmission loss(TL)was used as the inversion performance evaluation standard.The collected experimental data verified the effectiveness of the joint inversion framework of cooperative and opportunity sound source.