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, and determining the target differential phase with the preset algorithm, the demodulation signal abnormality caused by coherent fading noise is solved, and more accurate phase information extraction and higher equipment reliability are achieved.

CN119533636AActive Publication Date: 2025-02-28LASER RES INST OF SHANDONG ACAD OF SCI
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Patent Information

Application Number
CN202510105087.7
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-01-23
Publication Date
2025-02-28
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 wave sensing system, extracting sub-voltage signals of different bandwidths based on bandpass filtering technology, demodulating the differential phase of each sub-voltage signal using phase demodulation technology, and determining the target differential phase with coherent fading noise less than or equal to the noise threshold based on a 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 invention relates to the technical field of optical fiber sensing, in particular to a coherent fading noise suppression method and system. The coherent fading noise suppression method comprises the following steps: acquiring a voltage signal output by a distributed optical fiber sound wave sensing system; determining a plurality of sub-voltage signals corresponding to different bandwidths in the voltage signal based on a band-pass filtering technology; demodulating and determining a differential phase corresponding to each sub-voltage signal based on a phase demodulation technology; based on a preset algorithm, determining a target differential phase in the plurality of differential phases; the preset algorithm comprises a rotation vector sum algorithm or a Rayleigh signal strength discrimination algorithm. The problem of demodulated information error caused by abnormal or distorted signal demodulation is reduced, and the suppression of coherent fading noise during demodulation is realized.
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Citation Information

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