Passive Intrusion Detection System.
Patent, Filed 10 May 96, patented 6 Jan 98,
DEPARTMENT OF THE NAVY WASHINGTON DC
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An RF energy source transmits energy into a transmission cable that has a characteristic impedance subject to change by deformation of the cable. The cable is buried along a path that corresponds to a perimeter to be monitored. When an intruder places weight in the vicinity of the cable the cable deforms and changes its characteristic impedance. Consequently a portion of energy transmitted into the cable reflects back where time-domain or frequency-domain reflectometry apparatus uses the reflected energy to identify the location of the intrusion along the cable and provide other characteristics of the intruder.
- Radio Countermeasures