Pipeline anti-vandalism monitoring system based on time division multiplexing interferometric fiber optic sensor array

Abstract

A pipeline anti-vandalism monitoring system based on time division multiplexing (TDM) interferometric fiber optic sensor array is proposed and demonstrated in this paper to realize the anti-vandalism monitoring of buried pipelines. The sensor unit of the TDM quasi-distributed system can be responsible for a continuous monitoring area due to its high sensitivity through sensitization. Therefore, the TDM-supported quasi-distributed sensor technique only needs to dig at several sites to avoid digging deeply into ground along the pipeline. This can greatly reduce the system cost and accelerate the construction process. In addition, a phase detection method based on the rectangular pulse binary (RPB) phase modulation is used to realize the phase detection, and a field programmable gate array (FPGA)-based signal acquisition interrogation controller is adopted to realize the rapid and real-time acquisition of returned interference signals in the system. For the demodulated phase signals, by judging the three eigenvalues of level crossing time-domain statistics, peak-to-average ratio, and short-term energy, effective anti-vandalism alarm can be achieved. The system is tested and verified. The experiment results show that the system can achieve effective and real-time anti-vandalism alarm with accuracy rate over 90% within 1 ms.