Combination intrusion detector system having correlated ultrasonic and microwave detection sub-systems
US4625199A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 14, 1985 |
| Grant date | Nov 25, 1986 |
| Priority date | — |
| Expiry date | Jan 14, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/862
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A motion alarm system having a combination of microwave and ultrasonic subsystems is operative to reliably detect true moving targets and to discriminate false targets both caused by target motion reflected outside the surveillance space and by noise and other interfering phenomena. Microwave and ultrasonic signals received from the surveillance space are separately processed to provide ultrasonic motion detection signals and a microwave motion detection signal. A signal processing circuit interdependently combines the signals for producing a correlated system event signal. The presence of a true moving target within the surveillance space produces sufficient correlation to cause the system event signal to meet predetermined alarm criteria. The presence of either interfering phenomena or unwanted reflected outside signals, or both simultaneously, produces insufficient correlation to cause the system output signal to meet the predetermined criteria. An alarm status is thereby only provided in response to a true moving target within the surveillance space, but not in response to the occurrence of error producing sources for the sub-systems individually or collectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.