Based On The Phase Sensitive Optical Time Domain Reflection Technology Of Distributed Optical Fiber Fence Intrusion Monitoring Application Research

The distributed fiber fence intrusion monitoring system based on phase-sensitive optical time domain reflectometer (Φ-OTDR) technique is a new type of border security monitoring system, which has less complexity and faster speed of data processing than the distributed fiber fence intrusion monitoring system based on Brillouin optical time domain reflectometer (BOTDR). In addition, the distributed fiber fence intrusion monitoring system based on interference technique has drawbacks of polarization fading, short application distance, complex data processing etc. Moreover, the intrusion monitoring system based on interference technique is not sensitive to external disturbance when the phase difference is0or π; At last the intrusion monitoring system based on the polarization optical time domain reflectometer’s polarization state is easily influenced by temperature and outside environment, the system of this type also can’t accurately separating temperature and stress influence on the system. So the distributed fiber fence intrusion monitoring system based on phase-sensitive optical time domain reflectometer technique has broad prospects in the field of perimeter security applications, and it will be the mainstream research direction of the intelligent security in future.In this thesis, a distributed fiber fence intrusion monitoring system is studied and an intrusion detection and location method based on the wavelet decomposition analysis is proposed for avoiding the excessive nuisance alarms in the field applications. The work mainly includes:(1) Starting from the theory of Phase-OTDR, key factors which have inportance impacts on the system performance are discussed.(2) Detection and localization algorithm is studied in this paper. Different wavelet decomposition methods are compared for extracting the singularity information buried in the noisy intrusion signals of the distributed fiber fence intrusion monitoring system based on Φ-OTDR, and a comprehensive judgment method is proposed, which combines several different wavelet decomposition methods to reduce the system’s false alarm rate. (3) The hardware of the system is designed, realized and optimized for the field application, which includes:parameters and dimensions of the equipment are designed, and all of components are integrated in a4U type equipment box and the system showed a good performance. The smaller and more portable system makes itself more practical.(4) Software of the distributed fiber fence intrusion monitoring system based on Φ-OTDR is realized using C++, MFC, database etc.. The software system can basically meet the requirements of the practical applications.(5) The indoor and outdoor tests are carried out and the experiment results verified the validity of the algorithm and the system.