Phase sensitive optical time-domain reflectometer (phi-OTDR) sensing signal noise separation and signal extraction method

Abstract

The invention discloses a phase sensitive optical time-domain reflectometer (phi-OTDR) sensing signal noise separation and signal extraction method, a longitudinal time sequence signal of each point of a phi-OTDR space is used as a processing object, multi-scale decomposition is performed for the time sequence signal by utilization of wavelet transforming, component signals in each scale are analyzed and reorganized in a selective mode, undulate background noise, acoustic waves and other time-varying interference signals are separated, real disturbance invasion signals are extracted, not only can undulate background noise be restrained, but also influences from other complicated time-varying interference noise are avoided, an invasion detection accuracy rate can be effectively improved, a system false alarm rate is reduced, detection performance of an invasion detection system based on a phi-OTDR in an actual complicated noise environment is improved, and significant application requirements in perimeter security, long-distance pipeline safety, large structure health monitoring and the like for a country can be met.

Description

technical field [0001] The invention relates to the fields of perimeter security, long-distance pipelines and large-scale structure safety monitoring, in particular to a phase-sensitive optical time domain reflectometer sensing signal noise separation and signal extraction method. Background technique [0002] The safety of national defense, military, civilian facilities and people's lives and properties is a major issue related to the national economy and people's livelihood. Therefore, my country has major needs in the fields of perimeter security, long-distance pipeline safety, and large-scale structural health monitoring. Phase-sensitive optical time domain reflectometry (Phase-sensitive optical time domain reflectometry, Φ-OTDR) is a typical fully distributed optical fiber sensing technology with high sensitivity, passive throughout, and can continuously sense dynamic parameters such as strain and vibration on the transmission path Since the detection distance and multi...

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Problems solved by technology

[0004] Aiming at the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a phase-sensitive optical time domain reflectometer sensing signal noise separation and signal extraction method to solve the problem of low signal-to-noise ratio of the sensing signal in the existing system and the impact on the external environment. All kinds of interference are sensitive, and at the same time, the optical system is affected by environmental temperature and other factors, and the phase noise caused by the inevitable frequency drift phenomenon causes large fluctuations in the received signal, which makes it difficult to detect real disturbance intrusions, and the system has a high false alarm rate and false alarm rate. The problem

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