Method of and apparatus for surveying an area
US4053877A · kind A · utility
8Cited by
9References
1Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 16, 1975 |
| Grant date | Oct 11, 1977 |
| Priority date | — |
| Expiry date | Dec 16, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2497
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A security system for surveying an area such as a prison or airport, the security system comprising three coaxial cables which are placed in the ground parallel to and spaced apart from each other, the center cable being provided with a modulated signal which is received by the outer two cables, and the received signal being caused to vary and trigger an alarm if there is an unauthorized movement in the surveyed area.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.