Perimeter Security System Based on SAW Vibration Sensor

Abstract

This paper presents the concept of a perimeter protection system with acceleration sensors with the acoustic surface wave. The system consists of subsystems. Subsystems are connected with a monitoring centre. Every subsystem consists of an identical set of acceleration sensors with the acoustic surface wave, a measurement generator and a quadrature phase demodulator and a reference generator, the frequency of which is dierent in every subsystem. The acoustic surface wave acceleration sensors are of a dierent frequency of free vibrations. The spectrum of the output signal from a subsystem is situated around the frequency which equals the dierence between the measuring generator frequency and the reference generator frequency. Therefore the spectrum of every vibrating sensor is located in a dierent known frequency range. The analysis of the spectrum of signals from subsystems performed in the monitoring center allows monitoring the vibration status of every sensor included in a system. A system can consist of many identical acoustic surface wave acceleration sensor sets. This allows constructing a perimetrical protection system with acoustic surface wave acceleration sensors of parameters of which are comparable to parameters of presently oered perimeter protection systems. Results of the experimental research of the operation of the acoustic surface wave acceleration sensor in a subsystem are presented.