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Distributed disturbance sensor on basis of Rayleigh scattering spectrum related coefficient and demodulating method thereof

A technology of correlation coefficient and Rayleigh scattering, applied in the field of distributed disturbance sensing devices, can solve the problems of poor positioning accuracy

Active Publication Date: 2012-08-15
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the disadvantage of this method is that the positioning accuracy is poor, about 50-100m, and the test length does not exceed 20km

Method used

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  • Distributed disturbance sensor on basis of Rayleigh scattering spectrum related coefficient and demodulating method thereof
  • Distributed disturbance sensor on basis of Rayleigh scattering spectrum related coefficient and demodulating method thereof
  • Distributed disturbance sensor on basis of Rayleigh scattering spectrum related coefficient and demodulating method thereof

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Embodiment 1

[0022] Embodiment 1. Device for distributed disturbance sensing based on Rayleigh scattering spectral correlation coefficient

[0023] Such as figure 1 As shown, the device includes:

[0024] Tunable laser 1: used to provide light source for the optical frequency domain reflection system, the light source adopts ultra-narrow linewidth linearly tuned whispering gallery mode self-injection mode-locked laser light source, its optical frequency can be linearly scanned, and it is controlled by the tuning signal control module 21 , the module generates a triangle wave or a sawtooth wave to drive a tunable laser according to requirements

[0025] 1:99 beam splitter 4: the output light of laser 1 enters through port a of beam splitter 4, and is distributed from ports b and c to the clock trigger system 24 based on the auxiliary interferometer and main interferometer 25;

[0026] Auxiliary interferometer-based clock trigger system 24: realize equal optical frequency spacing sampling...

Embodiment 2

[0029] Embodiment 2. Demodulation method of distributed disturbance sensing based on Rayleigh scattering spectral correlation coefficient

[0030] Such as figure 2 As shown, the steps of the demodulation method of the present invention are:

[0031] In the first step, according to the principle of linear frequency modulation, the linearly tuned laser light generated by the tunable laser 1 enters the main interferometer 25, and in the main interferometer 25, the beat frequency is formed by the backscattered light in the sensing optical cable 15 and the reference light in the reference arm 22 After the interference signal passes through the polarization beam splitters 16 and 17, two paths of beat frequency interference signals X and Y of orthogonal polarization are obtained, and fast Fourier transform is performed on these two paths of signals respectively to obtain signals FFT{X} and FFT{ Y}, select each position in the sensing optical cable in turn through the moving window; ...

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Abstract

The invention relates to a demodulating method of a distributed disturbance sensor based on a Rayleigh scattering spectrum related coefficient. The distributed disturbance sensor adopts a technical method of optical frequency zone reflection and beat frequency interference of a laser source of a linear tuning ultra-narrow line width echo wall mold self-injecting locked mode. The distributed disturbance sensor comprises a main interferometer used for obtaining sensing signals and an auxiliary interferometer used for providing clock triggering signals for a collecting device. The demodulating method comprises the following steps: obtaining different beat frequency signals through a linear tuning light source and converting information of a wavelength zone to the information of distance zones of positions of corresponding cables by utilizing fast Fourier transform. Signals of the sensing optical cables are selected in the distance zones by a movable window, and then, are converted to the wavelength zone through plural fast Fourier inversion to form the Rayleigh scattering spectrums. The Rayleigh scattering spectrums disturbed by the outside world at different moments are compared, i.e., the disturbed Rayleigh scattering spectrums at the different moments are compared. The demodulating method is characterized in that information of whether the sensing optical cables is disturbed or not and the information of the disturbance intensity are obtained through related coefficients.

Description

technical field [0001] The invention belongs to the technical field of distributed optical fiber sensing instruments. Specifically related to a distributed disturbance sensing device and demodulation method based on Rayleigh scattering spectral correlation coefficient Background technique [0002] With the continuous development of society, the perimeter security of important areas such as airports, military bases, governments, prisons, banks, oil depots, and oil and gas pipelines, and the security of submarine or land communication optical cables are particularly important. The distributed optical fiber disturbance sensing system can realize intrusion disturbance detection and positioning, and has the characteristics of long-distance monitoring, high-precision positioning, low energy dependence, high environmental tolerance, anti-electromagnetic interference, and anti-corrosion. [0003] At present, there are mainly two types of distributed optical fiber disturbance sensin...

Claims

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Application Information

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IPC IPC(8): G01D5/26
Inventor 刘铁根刘琨丁振扬江俊峰杜阳李定杰
Owner TIANJIN UNIV
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