Multipoint disturbance positioning method of fiber-distributed disturbance sensor

Abstract

The invention discloses a multipoint disturbance positioning method of a fiber-distributed disturbance sensor. The fiber-distributed disturbance sensor is a fiber-distributed disturbance sensor based on double Mach-Zehnder interferometers. The method includes the steps: S1, obtaining a first output signal and a second output signal respectively through the double Mach-Zehnder interferometers; S2, respectively preprocessing the first output signal and the second output signal to obtain phase information in the first output signal and the second output signal; S3, performing time domain cross-correlation processing for the processed first output signal and the processed second output signal; and S4, performing frequency domain spectral analysis processing for results after the time domain cross-correlation processing, and extracting position information of a multipoint disturbance signal. By the aid of the method, the fiber-distributed disturbance sensor which is simple in structure and low in hardware cost can be used for achieving multipoint disturbance positioning.

Description

technical field [0001] The invention relates to the technical field of optical fiber disturbance signal monitoring, in particular to a multi-point disturbance positioning method of an optical fiber distributed disturbance sensor. Background technique [0002] The fiber optic distributed disturbance sensor can monitor the disturbance (time-varying signal) at any point on the sensing fiber, obtain the time domain waveform of the disturbance signal, judge according to the nature of the disturbance event, and give an alarm message; spatial location information. [0003] According to different working principles, optical fiber distributed sensors can be divided into sensing technologies such as interferometer type, fiber grating type, optical time domain reflectometer type, optical frequency domain reflectometer type and intensity modulation type. Among them, the interferometer-type distributed sensor has excellent characteristics such as simple implementation principle, high se...

AI Technical Summary

Problems solved by technology

[0007] 1) The premise of disturbance signal demodulation and positioning is assuming that the system is affected by a small signal (that is, the phase difference caused by the disturbance signal is less than 0.1rad); 2) The relative phase shift generated by the disturbance is a function of the position on the Sagnac ring, The sensitivity of the sensor at the center of the ring is close to zero; 3) due to the use of devices such as wavelength division multiplexers (WDM), the hardware cost and structural complexity of the system are increased; 4) due to the non- Ideal type, so that there is a certain amount of optical serial interference, which leads to errors in the output results of the system, thereby increasing the false alarm rate of the system and reducing the positioning accuracy of the system

[0008] The above defects seriously affect the reliability of the sensor in the actual monitoring application, which limits the actual implementation of the scheme

Images