BOTDR cross-correlation peak finding method based on defective spectrum splicing

A cross-correlation and incomplete technology, applied in the field of BOTDR peak-seeking technology, can solve the problem of not being able to obtain the strain information along the high-speed rail, and achieve the effect of making up for insensitivity and improving the sensing effect

Inactive Publication Date: 2017-08-22
NANJING UNIV
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  • Application Information

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Problems solved by technology

Since the incomplete spectrum cannot determine the correct peak frequency of the Brillouin spectrum through Lorenz curve fitting, the...

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  • BOTDR cross-correlation peak finding method based on defective spectrum splicing
  • BOTDR cross-correlation peak finding method based on defective spectrum splicing
  • BOTDR cross-correlation peak finding method based on defective spectrum splicing

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Embodiment Construction

[0037] The technical solutions of the present invention will be described in further detail below in conjunction with the accompanying drawings. The implementations described with reference to the accompanying drawings are exemplary and are only used to explain the present invention, rather than to limit the present invention.

[0038] The invention obtains the real Brillouin spectrum peak frequency by combining the obtained incomplete spectrum and performing cross-correlation calculation with the standard Lorentz curve under the condition of constant sweep frequency. At the same time, through the pre-order experiment, on the basis of meeting the error range required by the actual application, determine the number of spectrum spelling and optimize the peak-finding efficiency.

[0039] It is known that the Brillouin spectrum is in the form of a Lorenz curve, and its expression is:

[0040]

[0041] In the formula, Ω is the angular frequency; g p is the peak Brillouin gain; ...

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Abstract

The invention discloses a BOTDR cross-correlation peak finding method based on defective spectrum splicing. The method comprises steps of in case of a certain scanning frequency, carrying out spectrum splicing on acquired defective spectrums; carrying out correlation operation on the spectrum splicing and standard Lorentzen curves to obtain the real peak value frequency of a Brillouin spectrum; and through a preorder experiment, determining spectrum splicing frequency and optimizing peak finding frequency on the basis of meeting error ranges required in actual application. According to the invention, by carrying out splicing processing on the data after measurement, the cross-correlation algorithm is properly used when the peak value frequency of the Brillouin spectrum by use of the defective spectrums, so efficiency and accuracy for carrying out Brillouin peak finding on the defective spectrums are improved; insensitivity to external interference of rapid change of the BOTDR is overcome; sensing effects of the BOTDR in an extreme environment are improved; and the method has an important meaning for actual engineering application.

Description

technical field [0001] The invention relates to a BOTDR peak-finding technology based on a cross-correlation algorithm for improving the efficiency of Brillouin spectrum peak-finding, and belongs to the technical field of BOTDR measurement. Background technique [0002] Brillouin optical time-domain reflectometry (BOTDR) is a sensing technology based on spontaneous Brillouin scattering of optical time-domain reflectometry. The technique only needs to inject pulsed light from one end of the fiber, and sense by detecting the spontaneous Brillouin scattering spectrum of the pulsed light from the same end. Brillouin scattering is caused by the interaction between the optical field in the fiber and its induced acoustic field, and the scattered light has a frequency shift relative to the incident light, which is the so-called Brillouin frequency shift (BFS). The basic principle of BOTDR sensing is: the Brillouin frequency shift is related to the strain on the optical fiber, and t...

Claims

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Application Information

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IPC IPC(8): G01L1/24G01D5/353
CPCG01D5/353G01L1/242
Inventor 李密陈媛沈文丽李浩李文琛唐艳秋洪轶锋张旭苹
Owner NANJING UNIV
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