Research On Signal Propagation Characteristics And Background Noise Simulation Of Underwater Acoustic Array

In order to improve the real-time and fidelity of underwater acoustic array signal simulation,the simulation of acoustic propagation characteristics and the simulation of background noise of underwater acoustic array is carried out in this paper.The real-time optimization method of acoustic propagation characteristics simulation and the spatial correlated underwater ambient noise time series generation method of array are studied.A broadband channel phase-frequency response unwrapping method based on sound velocity profile and transmission and reception distance is proposed for the problem that the phasefrequency response of the broadband channel has unwrapping phase ambiguity at low frequency resolution.The method realizes the reconstruction of the broadband channel phasefrequency response at low frequency resolution.In the simulation process of wide-band signal acoustic propagation characteristics based on Fourier synthesis,the interpolation method of channel amplitude and phase-frequency response separation is studied for the problem of frequently calling the sound propagation calculation model when constructing the channel frequency response.In the range of average amplitude error less than 15% and average phase error less than 0.2 rad,the method achieves 30 times interpolation of channel frequency response.Aiming at the problem that the propagation delay causes the channel impulse response to be long,the interception method of channel impulse response function based on group delay is studied.The method realizes that the intercepting window contains more than 97% of the channel impulse response energy,and the intercepting window length is less than 0.1 times the length of the channel impulse response function.Based on the spatial correlation characteristics of underwater ambient noise,a time-series generation method for underwater acoustic noise based on dynamic decomposition of frequency bands is proposed.The method dynamically decomposes the effective frequency band according to the simulated accuracy of the spatial correlation coefficient of the underwater ambient noise.This method is suitable for situations where the simulation accuracy of spatial correlation coefficients needs to be controlled.A method for generating time series of underwater ambient noise based on Fourier transform is studied.The method performs CHOLKESY decomposition on the spatial coherence function matrix of the underwater ambient noise in the frequency domain,and multiplies the decomposition matrix by the array underwater ambient noise spectrum.This method is suitable for situations where the spatial resolution of the spatial coherence function needs to be controlled.In the case of low simulation accuracy requirements,the method based on frequency band dynamic decomposition has higher simulation time efficiency;in the case of higher simulation accuracy requirements,the Fourier transform based method has higher simulation time efficiency.