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Single hydrophone normal wave modal separation method and system based on compressed sensing

A technology of compressed sensing and single hydrophone, which is applied in special data processing applications, complex mathematical operations, design optimization/simulation, etc., and can solve problems such as separation performance degradation and interference

Active Publication Date: 2021-05-11
INST OF ACOUSTICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, one of the main application limitations of the Warping transform is that the normal waves in the waveguide are both reflective or refractive, that is, they need to have the same mode type
If the mode contains both reflection and refraction normal waves, the separation performance of Warping transformation will be significantly reduced, because the two types of normal waves will interfere with each other after transformation

Method used

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  • Single hydrophone normal wave modal separation method and system based on compressed sensing
  • Single hydrophone normal wave modal separation method and system based on compressed sensing
  • Single hydrophone normal wave modal separation method and system based on compressed sensing

Examples

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Embodiment 1

[0104] like figure 1 As shown, Embodiment 1 of the present invention proposes a method for separating normal wave modes of a single hydrophone based on compressed sensing, and the specific steps are as follows:

[0105] 1. According to the shallow sea sound propagation theory, the phase velocity C of the normal wave propagating in the waveguide p Should meet C w ≤C p ≤C b , where C w Indicates the speed of sound in sea water, C b represents the speed of sound at the bottom of the sea. Therefore, for the frequency band [f 1 , f F ] on the first frequency point f 1 , we start from the interval [2πf 1 / C b ,2πf 1 / C w ] in the hypothetical value of uniform sampling of M horizontal wavenumbers. Since the speed of sound in seawater and seabed is uncertain in practical applications, C w Take the minimum speed of sound over the entire sea depth, C b Take an empirically larger value, such as 2000 or 2500m / s.

[0106] 2. Given the first frequency point f in step 1 1 Co...

example 1

[0116] Simulation example 1, reflective hydrological environment

[0117] The reflective hydrological environment refers to the reflection of normal waves of all orders on the sea surface and seabed in this kind of waveguide environment, that is, there is no refraction type of normal wave in the waveguide. This hydrological environment is simpler because all normal wave modes have the same property of being reflected at the sea surface and seafloor interface.

[0118] figure 2 The waveguide environment shown is a typical reflective hydrological environment. The seawater sound velocity is equal to 1500m / s in the entire sea depth, the sea depth is 80m, and the seabed is a semi-infinite liquid seabed model. figure 2 shown. The depth of the sound source is 10m, the depth of the receiver is 70m, and the distance between the sound source and the receiver is 10km. The simulated signal frequency band is 90-120Hz, and the frequency interval is 0.1Hz.

[0119] based on figure 2 ...

example 2

[0123] Simulation example 2, downward refraction-like hydrological environment (negative gradient hydrological environment)

[0124] The second calculation example is the downward refraction-like hydrological environment, that is, the negative gradient hydrological environment. This kind of hydrological environment often appears in summer, and the seawater sound velocity gradually decreases with depth. Figure 8(a) shows a typical summer negative gradient hydrological sound velocity profile. The speed of sound drops from 1535m / s at the sea surface to 1498m / s near the seabed. Other environmental parameters and sound source receiver settings are the same as figure 2 in the same. For this environment, the normal wave may reverse below the surface of the sea. Figure 8(b) shows the theoretically calculated phase velocity corresponding to the first six order normal waves in the 50-300Hz frequency band. The dotted line in the figure indicates that the sound velocity at the sea sur...

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Abstract

The invention relates to the technical field of underwater acoustic signal processing, in particular to a single hydrophone normal wave modal separation method and system based on compressed sensing, and the method comprises: obtaining a horizontal wave value of a broadband normal wave according to an approximate modal dispersion relation; based on a compressed sensing theory, constructing a dictionary matrix of a sparse solving problem by horizontal wave values; according to the dictionary matrix and a broadband frequency domain sound pressure vector received by the single hydrophone, constructing a sparse signal model by adopting a compressed sensing theory, and solving and calculating by utilizing a compressed sensing implementation algorithm to obtain a sparse vector complex coefficient; and, according to the sparse vector complex coefficient and the dictionary matrix, recovering each separated normal wave mode. The method is wider in applicable scene and can be suitable for the condition that refraction type and reflection type normal positive waves exist at the same time under the negative gradient hydrological condition, and the known accurate seawater sound velocity profile and seabed parameters are not needed.

Description

technical field [0001] The invention relates to the technical field of underwater acoustic signal processing, in particular to a single hydrophone normal wave mode separation method and system based on compressed sensing. Background technique [0002] In shallow sea environments, normal wave theory is a powerful tool for modeling acoustic propagation of low frequency signals. According to the normal wave theory, the far-field low-frequency signal is mainly composed of a small number of propagating normal wave modes. Achieving separation of individual normal wave modes can be used in various applications in hydroacoustics, such as matched-mode sound source localization, geoacoustic parameter inversion, and acoustic tomography. Therefore, the separation method of normal wave modes in shallow seas has always been a research hotspot in hydroacoustics. [0003] Compared with the method of extracting normal wave modes based on horizontal or vertical array signals, the mode separ...

Claims

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Application Information

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IPC IPC(8): G06F30/20G06F17/14G06F17/18G06F17/16
CPCG06F17/14G06F17/16G06F17/18G06F30/20
Inventor 牛海强李整林宫在晓王海斌
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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