Fiber optic perimeter protection sensor with intruder localization

摘要

This paper presents investigation results of a new generation of the fibre optic perimeter sensor in a two Sagnac interferometers configuration. This system can detect a potential intruder and determine its position along a protected zone. A multiresolution wavelet analyses of the signal is used to determine its start point. First, we made use of decomposition, thresholding and reconstruction of the signal by means of a Daubechies wavelet. Consequently, high-frequency noise was removed from the signal. Next, the signal was exposed to an approximation process by means of a multiresolution Haar wavelet. Statistical analysis of this signal enabled us to determine an amplitude criterion for calculation of a start point for slowly-changeable signals. The criterion was a standard deviation of the amplitude increase of the signal after approximation. Arrangement of a laboratory model of the sensor and its signal processing scheme is presented. During research of a laboratory model, it was possible to detect the position of the disturbance with resolution of about 20 m along a 6-km long section.