Year
1986
Abstract
Buried Line Field Disturbance Sensors used for the purpose of outdoor perimeter intrusion detection are unique in the sense that they are covert and terrain following. They possess an inherently low false alarm rate, being immune to seismic and acoustic changes, as well as wind, snow and ice. Considerable effort has been spent in recent years to develop an effective Buried Line Sensor using leaky (or ported) cable technology. To date, a modular CW (Continuous Wave) approach to designing such a sensor has proven to be the most effective compromise in terms of cost, performance and installation. Leaky cables differ from conventional coaxial cables in their ability to leak energy or receive energy from the external environment through apertures which are introduced into the outer shield. Proper design of a leaky cable sensor requires an in-depth knowledge of the coupling performance and attenuation characteristics of the sensor cable to be used. The \"Forward Wave\" (codirectional) method of detection is discussed. This paper contains theoretical and experimental expressions developed to demonstrate operation in terms of cost, performance and ease of installation. In practice, a forward wave sensing approach, in conjunction with high pass filtering to eliminate environmental factors as well as the high, fixed return signal eliminates problems associated with expensive cable grading and installation costs.