Pipeline Intrusion Detection and Location Based on Phase-Sensitive Optical Time Domain Reflectometer

Since fiber distributed vibration sensing (DVS) system based on phase-sensitive optical time domain reflectometer (Φ-OTDR) is extremely sensitive to the ambient environment, how to improve signal-to-noise ratio (SNR) and obtain vibration signal from background noise has become a key problem in the field. In this paper, firstly, based on the analysis of the wavelet high frequency component location algorithm and the separating averaging and differential algorithm, an improved separating averaging and differential algorithm is proposed by introducing an interval. Then cell average constant false alarm rate (CA-CFAR) detection algorithm is used to set the adaptive threshold. Finally, the continuous vibration section is found according to the influenced-spatial scale of the pipeline intrusion vibration, and the middle position of the section is judged to be the vibration position. The experimental results show that the positioning algorithm has less positioning error, shorter runtime and higher SNR. The SNR can be as high as 9.3483dB and the computation amount of the next identification module is reduced.