Perimeter surveillance system
US4091367A · kind A · utility
Inventor
Key dates
| Filing date | Jun 15, 1976 |
| Grant date | May 23, 1978 |
| Priority date | — |
| Expiry date | Jun 15, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2497
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A location and ranging system using a pair of leaky coaxial cables to detect targets along a prescribed route. When used as a security surveillance system an intruder is treated as the target and the prescribed cable routing is the perimeter of the protected area. The cables are mounted parallel to each other with a separation sufficient so as to cause the two cables to be loosely coupled. A transmitter is connected to one of the cables to supply pulses of RF energy for propagation therealong. The presence of a target (any body which reflects or absorbs radio frequency energy) alters the magnitude and phase of the signal received at the other cable and, hence, provides a change in the return signal to a receiver connected to the other cable. This change in signal is processed digitally to discriminate between legitimate targets and very slow environmental changes and very high speed changes due to undesirable targets such as birds. A switching system is provided whereby each cable may be alternately connected to the transmitter and receiver thereby providing both detection of fault location and sufficient redundancy for continued operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.