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Method for detecting and judging objective by epeiric sea low frequency coherent vector sound field interference structure

An interference structure, low frequency technology, applied in radio wave measurement systems, instruments, etc., can solve the problems of vertical arrays that are not suitable for installation, ship damage, and inability to measure target azimuths.

Inactive Publication Date: 2008-09-24
HARBIN ENG UNIV
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AI Technical Summary

Problems solved by technology

[0005] Although the research on the vertical array time-reversal mirror and vertical array matching field is of great significance, the vertical array is not suitable for installation on a moving platform, and it is also easily damaged by ships in shallow seas, and the conventional vertical hydrophone array Unable to measure target bearing

Method used

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  • Method for detecting and judging objective by epeiric sea low frequency coherent vector sound field interference structure
  • Method for detecting and judging objective by epeiric sea low frequency coherent vector sound field interference structure
  • Method for detecting and judging objective by epeiric sea low frequency coherent vector sound field interference structure

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Embodiment approach 1

[0059] Embodiment 1: The numerical analysis of the reactive component of the vertical complex sound intensity of the single vector sensor is used for target specific depth discrimination.

[0060] By analyzing the characteristics of the sound intensity flow of the point source sound field in the Pekeris waveguide, the total sound intensity flow includes not only the individual sound intensity flow of each order of normal waves, but also the energy of mutual interference between each order of normal waves. The active component of the horizontal sound intensity flow changes periodically with the distance, which will affect the receiving signal-to-noise ratio. Although the reactive component of the vertical sound intensity flow does not participate in the transport of sound energy, it can be used to determine the specific depth of the target in signal processing when the monophonic vector sensor is properly placed.

[0061] It can be processed by a cross-spectrum processor, and i...

Embodiment approach 2

[0066] Embodiment 2: Dual-sensor sound pressure and vertical vibration velocity cross-spectrum analysis is used for target-specific depth discrimination.

[0067] When there is a third-order normal wave in the waveguide, the coherent structure of the sound field becomes more complicated, and the calculation result of receiving sound waves with a single vector sensor cannot be used for double-choice judgment, that is, the target depth cannot be classified. For this purpose, the cross-spectrum of sound pressure and vertical vibration velocity with two sensors is used for analysis. The double-sensor sound pressure and vertical vibration velocity cross-spectrum is similar in form to the vertical complex sound intensity, which can be called "vertical interactive complex sound intensity", that is, two sensors are used to measure the sound pressure and the vertical component of vibration velocity at different points. Take the imaginary part of the vertical interactive complex sound i...

Embodiment approach 3

[0068] Embodiment 3: Double-sensor sound pressure and horizontal vibration velocity cross-spectrum analysis.

[0069] The reactive component of the vertical complex sound intensity in the low-frequency sound field can classify the depth of the target. In order to classify the depth of the target more precisely, the cross-spectrum of the double-sensor sound pressure and the horizontal vibration velocity is studied, which is also called "horizontal interactive complex sound intensity". Its definition is similar to the vertical interaction complex sound intensity. The real part of the horizontal interactive complex sound intensity is taken as the active component, and the active component of the horizontal interactive complex sound intensity is used for analysis here. The active components of the horizontal complex sound intensity obtained by measuring sound pressure and vibration velocity at the same point are all positive values. Therefore, dual sensors with different depths ar...

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Abstract

The invention provides a method for using a shallow-sea low-frequency coherent vector sound field interference structure for detecting and identifying a target. The first step is that the Fourier transformation of the sound pressure and the vibration velocity signal is respectively carried out; the second step is that the Fourier transformation of the vector signal is conjugated; the third step is that the Fourier transformation of the sound pressure signal is multiplied by and the female court attendant of the Fourier transformation of the vector signal; the fourth step is that the real part or the imaginary part is obtained; the fifth step is that the judgment of the positive or negative sign is carried out; and the sixth step is that the depth classification of the target is given according to the judgment of the positive or the negative sign of the fifth step. The method develops the work against the passive detection of the remote target and the target depth judgment, in particular to the application purpose of the target depth judgment. The method has important application prospect in comprehensive marine monitoring, seashore early-warning system, small platform sonar, aviation acoustic buoy and other aspects.

Description

(1) Technical field [0001] The invention relates to a method for discriminating underwater targets and water targets, in particular a method for detecting and discriminating targets by using shallow sea low-frequency coherent vector sound field interference structures. (2) Background technology [0002] Target detection has always been an important task and purpose of sonar technology. After the target detection is completed, it is of great significance to realize the long-range passive direction finding, ranging, speed measurement and target depth discrimination of the target. It is also very important to be able to distinguish whether a long-range target is an above-water target or an underwater target, but the identification of an over-water target and an underwater target has always been a difficult problem to solve. For the passive direction finding, ranging, speed measuring and target depth discrimination of remote targets, especially the application purpose of target ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S7/52
Inventor 赵安邦惠俊英孙国仓余赟
Owner HARBIN ENG UNIV
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