A low-complexity algorithm for intrusion detection in a PIR-based Wireless Sensor Network

We present a low-complexity algorithm for intrusion detection in the presence of clutter arising from wind-blown vegetation, using passive infra-red (PIR) sensors in a wireless sensor network (WSN). The algorithm is based on a combination of Haar transform (HT) and support-vector-machine (SVM) based training and was field tested in a network setting comprising of 15-20 sensing nodes. Also contained in this paper is a closed-form expression for the signal generated by an intruder moving at a constant velocity. It is shown how this expression can be exploited to determine the direction of motion information and the velocity of the intruder from the signals of three well-positioned sensors.