Exterior Intrusion Sensors

Abstract

Intrusion detection systems consist of exterior and interior intrusion sensors, video alarm assessment, entry control, and alarm communication systems all working together. Exterior sensors are those used in an outdoor environment, and interior sensors are those used inside buildings. This chapter examines various aspects of exterior intrusion sensors, whose performance is described by three fundamental characteristics that include probability of detection, nuisance alarm rate, and vulnerability to defeat. It is important for the system designer to specify the detection criteria required or expected of a sensor or sensor system. This specification should be clear as to what will be detected, what actions are expected, and any other considerations such as weight or speed of movement. Nuisance alarm rate is a function of the number of nuisance alarms over a given time period. In an ideal sensor system, the nuisance alarm rate would be zero. It is found that passive sensors detect some type of energy that is emitted by the target of interest or detect the change of some natural field of energy caused by the target.