Positioning method for modal subspace reconstruction steady target in uncertain marine environment

Abstract

The invention provides a positioning method for a modal subspace reconstruction steady target in an uncertain marine environment. Firstly, an uncertain marine environment model is built, and a predictable modal subspace is determined through the second-order characteristic of a horizontal wave number; grids are drawn on the area where the target may occur in distance and depth, and copy field vectors on the grid points are reconstructed and normalized through the predictable modal subspace and a modal coefficient corresponding to the predictable modal subspace; signals received by each measurement hydrophone of a sonar array are obtained, and frequency domain data snapshots are obtained; a covariance matrix is obtained through the frequency domain data snapshots; the copy field vectors on the grid points and the covariance matrix R are processed, and the estimation of the position of the target is obtained. The positioning method for the modal subspace reconstruction steady target in the uncertain marine environment is hardly influenced by the uncertain environment, and the positioning performance is better than that of a traditional matching field positioning method and a steady maximum likelihood method.

Description

technical field [0001] The invention relates to a target positioning method. Background technique [0002] Realizing the effective positioning of underwater targets is one of the main purposes of sonar equipment, and finding a fast and robust target positioning algorithm has great engineering application significance. [0003] Modern sonar positioning faces challenges from two aspects. One is that the radiated sound source level of the target to be located is getting lower and lower. The sound source level of the aircraft is decreasing at a rate of 0.5-1dB per year, which poses a huge challenge to sonar positioning. The second is that the working environment of sonar has changed from deep sea to shallow sea environment. In shallow sea area, due to the influence of sea bottom, sea surface and various ocean inhomogeneities, sonar echoes show fluctuation and fading effects, which also makes sonar Targeting becomes more difficult. [0004] Robust target positioning methods in...

AI Technical Summary

Problems solved by technology

[0003] Modern sonar positioning faces challenges from two aspects. One is that the radiated sound source level of the target to be located is getting lower and lower. The sound source level of the aircraft is decreasing at a rate of 0.5-1dB per year, which poses a huge challenge to sonar positioning

The second is that the working environment of sonar has changed from deep sea to shallow sea environment. In shallow sea area, due to the influence of sea bottom, sea surface and various ocean inhomogeneities, sonar echoes show fluctuation and fading effects, which also makes sonar Targeting becomes more difficult

When this method has a high signal-to-noise ratio, the problem that the orthogonal projection cannot be completely zeroed due to the modal mismatch appears, resulting in the loss of positioning performance

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