Space surveillance apparatus with sound source and method of short-range space surveillance
US4755973A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1986 |
| Grant date | Jul 5, 1988 |
| Priority date | — |
| Expiry date | May 20, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/1609
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A space surveillance apparatus includes at least one source of sonic radiation driven by a driver circuit as well as a processing or evaluation circuit. Upon movement of an object, or presence of a foreign object within a monitored space, the processing circuit triggers an alarm signal. Each sonic source defines the volume of its own monitored space, according to the equation: EQU L=D.sup.2 /(4.lambda.), wherein: PA1 L=Length of main direction of radiation of the monitored space; PA1 D=Diameter of diaphragm of sonic source; and PA1 .lambda.=Wavelength of acoustic wave. The driver circuit drives the sonic source either in continuous mode, or in pulsed mode, and either at a constant wavelength or at a variable wavelength, i.e. in frequency modulation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.