Coherent fading noise suppression method and system

By extracting the sub-voltage signals of different bandwidths of the voltage signal in C-OTDR technology and demodulating their differential phases, the target differential phase with coherent fading noise being less than or equal to the noise threshold is solved, and a more accurate phase information extraction and higher DAS device reliability are achieved.

CN119533636BActive Publication Date: 2025-03-28LASER RES INST OF SHANDONG ACAD OF SCI
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Patent Information

Application Number
CN202510105087.7
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2025-01-23
Publication Date
2025-03-28
Estimated Expiration
2045-01-23

AI Technical Summary

Technical Problem

Coherent fading phenomenon in C-OTDR technology leads to abnormal or distortion of the demodulation signal, and the phase information cannot be extracted correctly, false alarms occur, affecting the normal use of DAS equipment.

Method used

By obtaining the voltage signal output from the distributed fiber acoustic sensing system, bandpass filtering technology is used to extract sub-voltage signals of different bandwidths, and the differential phase of each sub-voltage signal is demodulated using phase demodulation technology, and the target differential phase with coherent fading noise less than or equal to the noise threshold is determined based on the preset algorithm.

Benefits of technology

Reduce information error problems caused by abnormal adjustment or distortion signals, realize the suppression of coherent fading noise during adjustment, and improve the accuracy and reliability of DAS devices.

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Abstract

The present application relates to the field of optical fiber sensing technology, and specifically to a method and system for suppressing coherent fading noise. The method for suppressing coherent fading noise includes: obtaining a voltage signal output by a distributed optical fiber acoustic wave sensing system; determining multiple sub-voltage signals corresponding to different bandwidths in the voltage signal based on bandpass filtering technology; demodulating and determining the differential phase corresponding to each sub-voltage signal based on phase demodulation technology; determining a target differential phase among multiple differential phases based on a preset algorithm; the preset algorithm includes a rotating vector sum algorithm or a Rayleigh signal strength discrimination algorithm. The problem of demodulated information errors caused by abnormal or distorted demodulation signals is reduced, and the suppression of coherent fading noise during demodulation is achieved.
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