Field testing of outdoor intrusion detection sensors

Sensors for outdoor perimeter detection must reliably detect intruders under all possible intrusion threat scenarios while rejecting environmental stimuli including nearby human activity. For the outdoors a wide variety of detection principles are possible in order to provide a measurable signal of an intruder´s presence. Generally algorithms implemented in firmware are employed to differentiate the human characteristics from those of a changing environment. This paper is an update of an earlier paper presented in the 1990s that outlines the how´s and why´s of field testing employed to both develop outdoor sensors and also prove their detection performance in the intended environment. This paper also shows the results of testing various sensor types, and highlights the sensor limitations and the pitfalls of testing. Finally, the use of a test site to develop sensor control and display systems, or investigate novel sensor applications, is discussed. The test environment described is called SITE (Sensor Integrated Test Environment) located near Carp, Ontario, Canada. At this facility, virtually all existing all-weather outdoor sensor technologies, from buried line cables, through microwaves, passive IR, and barrier-attached sensors; taut-wire, and linear microphonic cables are deployed. These sensors are installed in typical operational configurations for assessment or comparison. Fortunately, at this facility environmental stimuli ranges from temperatures of -40°C to +35°C, with snow and freezing rain, and summer lightning. As a rural site, an assortment of wildlife, from groundhogs to deer, are typical nuisance alarm stimuli. In this environment, human and mechanical targets are used to assess the detection of real threats. To better address the environmental performance of sensors, a new element of sensor integration is also reviewed, namely the incorporation of video and weather data in the control and display component of a security facility. This assists operators in making a rapid assessment, or maintenance personnel for sensor adjustments. This technology is also employed in the sensor testing phase to help define the best implementation, and as a useful SITE testing tool.