Method for tracking depth of sound source autonomously in real time at deep sea under lower signal-to-noise ratio condition

Abstract

The invention relates to a method for tracking the depth of a sound source autonomously in real time at deep sea under a lower signal-to-noise ratio condition. According to the method of the invention, piecewise linear approximation processing is performed on a sound velocity profile, so that the direction of arrival information of signals on a vertical array is obtained; the information is utilized to obtain the autocorrelation function of the signals, and the autocorrelation function of the signals contains sound source depth information; a plurality of equations with low computational quantities are adopted to obtain sound source depths corresponding to each time delay coordinate of the autocorrelation function; the autocorrelation function is transformed into a function which adopts ahypothetical sound source depth as an independent variable, and the function is called a depth correlation function; and a smoothing filter is applied to the time sequence of the depth correlation function so as to weaken background noises, extract the correlation peaks of the signals and track a sound source depth. Compared with the calculation amount of a traditional ray model-based sound sourcedepth estimation method, the calculation amount of the method of the invention is greatly reduced; and time accumulation gain is obtained with a small calculation amount and low storage cost, and therobustness of the method of the present invention under the low signal to noise ratio condition is improved.

Description

technical field [0001] The invention belongs to the fields of underwater acoustic engineering, ocean engineering, sonar technology, etc., and relates to an autonomous real-time tracking method for sound source depth under the condition of low signal-to-noise ratio in deep sea. Under the following conditions, the method of autonomous real-time tracking of sound source depth is suitable for autonomous tracking of low sound source level broadband moving sound source depth in deep sea environment. Background technique [0002] In the deep-sea environment, the sound velocity of the deep-sea isothermal layer increases with the depth, and at a critical depth (typically 4500m-5500m), the sound velocity is the same as the maximum sound velocity near the sea surface. The direct wave (and sea surface reflected wave) between the sound source near the sea surface and the hydrophone below the critical depth is called a reliable acoustic path. Broadly speaking, when there is no critical d...

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Problems solved by technology

[0005] In order to avoid the deficiencies of the prior art, the present invention proposes a sound source depth autonomous real-time tracking method under the condition of low SNR in the deep sea, which overcomes the existing sound source depth based on the time accumulation effect in the actual low SNR environment. Disadvantages of tracking algorithms not working autonomously

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