Perimeter intrusion detection system with block ranging capabilities
US4887069A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1987 |
| Grant date | Dec 12, 1989 |
| Priority date | — |
| Expiry date | Nov 4, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2497
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An intrusion detection system of the type using cables arranged along a perimeter to be protected and sensing changes in the electrical field around the cables caused by the presence of an intruder. The cables are divided into sections or blocks and typically only one of the sections is energized at any time. The variations caused by an intruder at the selected sections are transmitted through the intervening section to the receiver portion of a transceiver located at one end of the cables. This indicates in which section intrusion has occurred. The system uses continuous wave excitation whereby the expense and complexity of high speed switching and timing of r.f. signals are avoided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.