A Weak Signal Enhancement Method in Underwater Sound Field

Abstract

The invention discloses an underwater acoustic field weak signal enhancement method. The method includes the following steps that: a parametric model of weak signal enhancement is established through utilizing a nonlinear wave equation; the nonlinear parameters of a medium are measured; the frequency and amplitude of weak signals in an acoustic field are estimated; a pump wave generator located at a position d meters before a receiving point R0 emits two columns of pump wave signals of which the angular frequencies are omega 2 and omega 3 respectively, and the energy of pump waves is converted into the energy of weak signal waves in the transmission process of acoustic waves; the amplitude of the pump wave signals is adjusted according to a transmitting-receiving distance d between the pump wave generator and a receiving hydrophone, so that the maximum gain point position of the receiving hydrophone can be consistent with the maximum gain point position of a weak signal enhancement model, and therefore, maximum enhancement of the weak signals can be realized. The enhancement effects of the enhancement method are not limited by array size, and the method is not sensitive to initial acoustic pressure level of signals, and synchronization conditions can be avoided. The enhancement method has strong stability.

Description

technical field [0001] The invention belongs to underwater acoustic weak signal enhancement technology, in particular to a weak signal enhancement method in an underwater sound field for improving the weak signal detection effect. Background technique [0002] The weak underwater acoustic signal refers to the weak underwater acoustic signal submerged by strong noise. Traditional underwater acoustic weak signal detection technology usually utilizes the statistical characteristics and correlation differences between noise and weak signal to realize the detection and extraction of weak signal. This detection method is mainly divided into two ideas: one is the detection based on time domain information, and the detection is realized by extracting characteristic parameters through various transformations; the other is based on the spatial information, which is realized by methods such as array gain and spatial filtering. weak signal detection. However, these traditional underwa...

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Problems solved by technology

The literature "Long-aperture parametric receiving arrays. J. Acoust. Soc. Am, 1975, Vol. 57, No. 5: 1150-1155." has discussed this method, but due to the existence of parametric array technology itself The problem of low gain and nonlinear efficiency, so this technology is limited to theoretical discussion and analysis

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