基于虚拟时间反转镜的垂直阵舰船辐射噪声级测量方法
Measuring ship-radiated noise level via vertical linear array based on virtual time reversal mirror
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摘要: 研究了利用垂直阵测量舰船辐射噪声过程中因水声信道的多径效应对测量性能产生的影响,建立了基于声场模型的舰船辐射噪声测量的数学模型,推导了基于虚拟时间反转镜辐射噪声测量的理论公式,提出了一种基于虚拟时间反转镜技术的垂直阵舰船辐射噪声级测量方法。该方法首先采用基于波束积分的SCOOTER模型,根据海洋环境参数计算出辐射声源至测量水听器之间的信道传输函数,然后,用计算出的信道传输函数对接收信号做虚拟时反处理,以消除或减弱信道多径效应对接收信号的影响,从而提高舰船辐射噪声级测量精度。针对典型的浅海声信道,进行了计算机仿真试验。结果表明,该方法能有效地进行舰船宽带辐射噪声测量,当阵元个数满足一定要求时,测量得到的声源级与实际声源级相比,误差小于1 dB。Abstract: By adopting the virtual time reversal mirror (VTRM) technique, the ship-radiated noise measurement formula using vertical linear arrays is derived based on the underwater acoustic models, and a method is proposed to measure the ship-radiated noise level which is generally affected by multi-path transmissions in the underwater acoustic environment. Firstly, the transfer functions between the source (the noise-radiating ship) and the measuring hydrophones are calculated by using the SCOOTER model based on wavenumber integration techniques with given environment parameters. And then, the source signal is retrieved by applying the transfer functions to the received signals and carrying out time reversal processing, in order to eliminate or alleviate the effects caused by multi-path transmission. Numerical simulations in a typical shallow water environment demonstrate the effectiveness of the proposed method. When the number of the measuring hydrophones satisfies a certain requirement, the difference between the source level estimated by VTRM method and the origin source level is less than 1 dB.