Application of wavelet analysis in underground embedded distributed optical fiber vibration monitoring system

Abstract

The distributed optical fiber vibration monitoring system is often used for intrusion detection in the area. Usually, the optical fiber cable is buried in 10 to 30cm or in the net type installation. When the surface is passed, it can locate its position accurately. The system is sensitive to the micro vibration, and the optical fiber vibration can be detected even by the small wind load. The distributed optical fiber vibration monitoring system can realize the on-line real-time monitoring of the vibration response of the dam. The system obtains the external vibration information by detecting the light intensity, phase, polarization state and other information of the reflected light signal of the echo. The captured signals are mostly short-time pulse signals, and the real-time processing ability of the system for the signal is required. At the same time, the vibration signal is manifested by the singular point mode of sudden change. Therefore, the feature extraction of the optical signal can be realized by the efficient singular point detection ability of the wavelet analysis. At the same time, the real-time and accuracy of the data processing can be greatly improved compared with the conventional cumulative average de-noising method. The accuracy of the domestic vibration measurement system can reach 50m. In this paper, the accuracy of the vibration measurement system can be improved to 15m by studying the algorithm.