A Signal Processing Method for Improving Efficiency of a Phase Sensitive Optical Time Domain Reflectometry System

Abstract

The invention discloses a signal processing method for improving efficiency of a phase-sensitive optical time domain reflection system. On the distance axis, the intermediate frequency signal obtained by filtering the beat frequency signal is equally divided into equal-width intervals connected end to end, and the midpoint position is selected as the interval index; iteratively performs "phase discrimination judgment of elements at both ends of the index matrix-index matrix length judgment-index matrix Mid-point segmentation" until the conditions are satisfied; the phase difference between the adjacent intervals of the disturbance area is calculated, and the phase difference between the adjacent intervals of the non-disturbance area is recorded as zero, and the same process is performed for the previous intermediate frequency signal; for any two adjacent intervals, the current time The differential operation is performed with the phase difference at the previous moment to obtain the change in phase difference between two adjacent intervals, and restore the vibration signal. The invention only uses single-mode sensing optical fibers without changing the traditional system structure, reduces the system computing burden by ignoring a large amount of invalid sensing information, and effectively solves the problem of poor real-time performance of the system caused by a large amount of signal data and a large amount of system computing.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a signal processing method for improving efficiency of a phase-sensitive optical time domain reflection system. Background technique [0002] The phase-sensitive optical time-domain reflectometry (Φ-OTDR) sensing system has the advantages of fast response speed and high sensitivity, and can realize distributed detection of weak disturbances. Broad application prospects. At present, in the research on Φ-OTDR at home and abroad, most of the detection is the intensity information of the Rayleigh scattering signal, and there are few quantitative measurements of the optical phase change caused by external disturbances. Pan Zhengqing of Shanghai Institute of Optics and Mechanics used the method of detecting phase to process Φ-OTDR data. This Φ-OTDR based on phase demodulation can obtain a higher signal-to-noise ratio (greater than 10dB) than amplitude demodu...

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Problems solved by technology

However, the demodulation signal of this scheme is affected by the light amplitude, and it is impossible to establish an accurate linear relationship between the external disturbance and the demodulation signal, which limits the application range of the Φ-OTDR optical fiber sensing system

At the same time, both of the above two solutions increase the complexity of the optical path and devices

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