This invention discloses a high-resolution distributed acoustic-vibration
demodulation method based on sweep-frequency optical deep anti-
fading. First, continuous linear sweep-frequency probe light is injected into an
optical fiber, and the original backscattered Rayleigh
signal containing information distributed along the
fiber is acquired through coherent beat frequency acquisition. Then, the original backscattered Rayleigh
signal undergoes
frequency domain demultiplexing and matched-filter
pulse compression processing to reconstruct multiple high-resolution time-domain complex envelope signals from a
single sweep. Next, the high-resolution time-domain complex envelope signals are input into a deep anti-
fading demodulation network, where amplitude-phase joint modeling achieves adaptive suppression of random
fading and
noise in the time-domain complex envelope
signal, outputting a de-fading phase sequence. Finally, the de-fading phase sequence is used for
phase difference demodulation, and combined with an optical time-of-flight positioning model, to achieve highly robust demodulation and
spatial positioning of vibration events. This method maintains
high resolution and robustness even under strong
noise, long distance, and deep fading conditions, making it suitable for distributed acoustic-vibration and
ultrasonic monitoring scenarios.