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Method for extracting dimension characteristics of underwater target based on space similarity

A feature extraction and underwater target technology, applied to radio wave measurement systems, instruments, etc., can solve the problems of discrete target orientation, great influence, complex shape of underwater targets, etc.

Inactive Publication Date: 2015-03-25
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

The main difficulty of these methods is that the shape of the underwater target is complex, the randomness and time-varying nature of the underwater acoustic environment lead to a large dispersion of the extracted target azimuth; at the same time, the complexity of the algorithm is also high; the shortcomings of the azimuth method are It is greatly affected by the target illumination angle (side angle), and there is a dead angle for identification

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  • Method for extracting dimension characteristics of underwater target based on space similarity
  • Method for extracting dimension characteristics of underwater target based on space similarity
  • Method for extracting dimension characteristics of underwater target based on space similarity

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Embodiment Construction

[0069] Below in conjunction with the accompanying drawings, the method for extracting underwater target scale characteristics based on spatial similarity proposed by the present invention will be described in detail:

[0070] Such as figure 1 As shown, the underwater distribution source-target environment. Suppose the distance R between the underwater target and the sonar; seawater sound velocity c=1450m / s; sonar speed v=30kn, that is, v=30×1852 / 3600m / s; the heading of the target is 0°; the carrier frequency f c =15kHz; sampling frequency f s =50kHz; the transmit signal is a single-frequency rectangular wave with a pulse width of 32ms.

[0071] Such as figure 2 As shown, the receiving hydrophone array structure diagram. Assume that the base array is an equally spaced linear array with M=16 array elements, and the array element spacing d is half a wavelength. The echo signal incident angle is

[0072] Such as image 3 As shown, a flow chart of a method for extracting ...

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Abstract

The invention provides a method for extracting the dimension characteristics of an underwater target based on space similarity. The method comprises the following steps of calculating the conventional beamforming space power spectrum of a distribution source based on ripple signals of the underwater target, utilizing point target space power spectra obtained by a space similarity theory and a classic theory to perform space similarity measurement, and finishing classification and recognition according to previously established space measurement threshold standards so as to extract the dimension characteristics of the underwater target. The method for extracting the dimension characteristics has the advantages that the influence of irradiation angles, base arrays and target distance parameters on the dimension characteristics is considered so as to conform with the visual recognition of the eyes to the dimensional target; three space similarity measurement methods are adopted in the process of extracting the dimension characteristics of the target, the defects of a single method are overcome, and the extracting and recognition reliability of the dimension characteristics of the underwater target is improved; and the conventional beamforming (CBF) method is used for calculating the space power spectrum of the distribution source target, and the space similarity calculation methods are relatively simpler and favorable to engineering realization.

Description

technical field [0001] The invention belongs to the technical field of underwater acoustic signal processing, in particular to a method for extracting underwater target scale characteristics based on spatial similarity. Background technique [0002] The usual azimuth estimation theory often assumes that the target is a point target, even if there are multiple targets, they are also assumed to be independent reflection points. However, in the actual environment, the target has a certain shape and volume, and each target, especially some large targets, will occupy a certain space in the orientation instead of a geometric point, that is, a certain spatial distribution in the orientation. We call this kind of goal a distributed goal. In order to estimate the parameters of this kind of target in a detailed structure, the traditional point target model cannot be used to describe it, but a distributed target model must be used to describe it, and the characteristics of specific ta...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S7/539
Inventor 邵杰王丽赵伟松仲雅琴
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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