Environmentally Induced Variation in the Detectability of Fence-mounted Intrusion Detection Systems

Seasonal differences in the normal stiffness of the chain-link fence panels at CRREL's intrusion detection system (IDS) research facility have been determined using a CRREL-developed fence characterization kit. These results quantify changes in the fence panels' response to loading that result from thermal contraction or expansion of the fence elements. To assess seasonal differences in IDS response to fence motion, the proximity- to-alarm status of three fence-mounted IDSs has been continually monitored. Weather-related diurnal patterns in the likelihood of occurrence of nuisance alarms have been determined. This information allows security personnel to anticipate when the detectability of fence-mounted IDSs will vary because of wind-induced motion of chainlink fences and temperature-dependent differences in fence stiffness.