Fence monitoring
Under fence monitoring various technical solutions for monitoring a fenced understood terrain. Monitoring the serving for the enclosure fence serves as an early warning of an intrusion to the monitored premises. A video surveillance along a fence is a fence monitoring, especially if it is automated by image processing methods.
Fence monitoring by sensor cable
A common method for fence monitoring is the attachment of a sensor line to the fence. In the coaxially constructed sensor line, an electrostatic field is built up between the outer shield conductor and the inner conductor, which when the line moves, generates a voltage change via the microphonic effect. The use of piezoelectric material between the screen and the core further enhances the sensor properties. Climbing over, overturning, lifting or cutting through the fence creates vibrations in the fence that cause the sensor cable to move. The generated voltage change is detected by an evaluation circuit, which usually has to be installed every 300 m. The approximate position of such a movement can also be identified via transit time measurements. The influences of wind movements etc. can be largely suppressed by signal processing. The system is not effective against intrusions that do not move the fence.
literature
- Robert L. Barnard: "Intrusion Detection Systems", Butterworth-Heinemann Verlag, 1988, 2nd edition, p. 91f.