Multi-channel vibration detection method based on coherent Rayleigh scattering and detection system thereof

Abstract

The invention provides a multi-channel vibration detection method based on coherent Rayleigh scattering and a detection system thereof. The detection system is improved as follows for the problem of relatively low utilization rate of an acquisition card in an optical-fiber vibration detection method based on coherent Rayleigh: a method for detecting vibration signals in a plurality of branches of sensor fibers by use of a delayer and a photoelectric switch in a staggered manner is adopted, and time-sharing vibration detection is performed on each sensor fiber by controlling the time of the delayer, and consequently, the detection of a plurality of branches of vibration signals is realized; besides, the acquisition card in a detection module does not need the input of a pulse control signal and is capable of realizing real-time data acquisition in a pulse period, and therefore, the utilization rate of the acquisition card is increased.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing signal processing, in particular to a multi-channel vibration detection method based on coherent Rayleigh scattering and a detection system thereof. Background technique [0002] Coherent Rayleigh scattering is also known as phase-sensitive optical time-domain reflectometry (Φ-OTDR). This technology combines the advantages of distributed optical fiber sensing technology and interferometric optical fiber sensing technology. Higher sensitivity. [0003] The realization principle of this technology is as follows: the narrow-linewidth laser becomes pulsed light after passing through the modulator, and the amplified pulsed light enters the sensing fiber. After entering the detector through the circulator, generally the interference signal is relatively weak and needs to be amplified and filtered before detection, and then data collection and processing. When a vibration signal acts on t...

AI Technical Summary

Problems solved by technology

When there is no pulsed light, there is no Rayleigh scattered light in the fiber. In order to reduce the collection of unnecessary data, the usual practice is to connect the trigger signal of the modulator to the acquisition card, trigger the acquisition card to collect data when there is pulsed light, and collect data when there is no pulsed light. The card does not collect data, which leads to low utilization efficiency of the collection card

At the same time, the current vibration detection devices based on this technology are one system corresponding to one sensing optical fiber. For areas that require multi-channel detection, such as urban pipe networks and regional perimeter security, multiple systems need to be installed, and the cost is relatively high.

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