Quad element intrusion detection
US4963749A · kind A · utility
15Cited by
6References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Feb 28, 1989 |
| Grant date | Oct 16, 1990 |
| Priority date | — |
| Expiry date | Feb 28, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S250/01
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A dual channel intrusion detection system comprising first and second radiation sensors. Each sensor has a pair of elements viewing adjacent zones of the protected area, the zones being slightly offset from each other in the direction of expected intruder movement. Sequence detection is provided for producing an intruder-present signal in response to simultaneous actuation of one element of each sensor when preceded by actuation of the other element of one of the sensors. Additional immunity from false triggering is obtainable if this sequence must be followed by actuation of the other element of the second sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.