High-resolution distributed acoustic vibration demodulation method based on sweep frequency light depth fading resistance

By combining continuous linear sweep frequency optical signals and deep learning networks, the fading problem of distributed fiber optic acoustic vibration sensing systems in long-distance and high-noise environments is solved, achieving high-resolution stable demodulation and accurate positioning, which is suitable for long-distance, high-bandwidth distributed acoustic vibration monitoring.

CN122171010APending Publication Date: 2026-06-09CHINA JILIANG UNIV
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Patent Information

Application Number
CN202610144012.4
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-02-02
Publication Date
2026-06-09

AI Technical Summary

Technical Problem

Existing distributed fiber optic acoustic vibration sensing systems are susceptible to interference fading under long-distance, high-resolution, and high-sensitivity conditions. Traditional methods are difficult to adaptively adjust, leading to signal distortion or detection blind spots. Furthermore, deep learning is not sufficiently applied in front-end physical demodulation.

Method used

Rayleigh scattering information is obtained by using a continuous linear sweep frequency optical signal. Combined with frequency domain demultiplexing and matched filtering compression, amplitude and phase joint modeling is performed using a deep learning network to achieve adaptive anti-fading demodulation. The Rayleigh scattering signal is spatially and temporally block-processed by the deep learning network to improve the signal-to-noise ratio and resolution.

Benefits of technology

It achieves stable demodulation at high resolution in long-distance and high-noise environments, improving the system's anti-interference and positioning accuracy, and is suitable for long-distance, high-bandwidth distributed acoustic and vibration monitoring scenarios.

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Abstract

The invention discloses an anti-fading high-resolution distributed acoustic vibration demodulation method based on sweep frequency light depth, which comprises the following steps: firstly, injecting continuous linear sweep frequency detection light into an optical fiber, and obtaining an original backward Rayleigh scattering signal containing optical fiber distribution information through coherent beat frequency; then performing frequency domain demultiplexing and matched filtering pulse compression processing on the original backward Rayleigh scattering signal, and reconstructing a single frequency sweep signal into multiple paths of high-resolution time domain complex envelope signals; inputting the high-resolution time domain complex envelope signal into a deep anti-fading demodulation network, realizing adaptive suppression of random fading and noise of the time domain complex envelope signal through amplitude-phase joint modeling, and outputting a de-fading phase sequence; and finally, phase difference demodulation is carried out by using the de-fading phase sequence, and high-robustness demodulation and spatial positioning of a vibration event are realized in combination with an optical flight time positioning model. The method can still keep high resolution and high robustness under the working conditions of strong noise, long distance and deep fading, and is suitable for distributed sound vibration and ultrasonic monitoring scenes.
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