Patent US3723738A successfully refreshed from Google Patents.
US3723738A
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Intrusion detection false alarm reduction system
Assignee: Motorola Solutions Inc
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Filing: 1971-05-20
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Granted: 1973-03-27
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Expires: 1991-05-20
Abstract
Abstract False alarm reduction means for an intrusion detection system are disclosed wherein two optical transmitting systems with highly directive beams alternately illuminate adjacent but nonoverlapping cross-sections. A signal processor indicates true target detection only when the target return from two or more successive pulses exceed a predetermined threshold which implies that the target is sufficiently large that it intersects both beams.
Inventors
- 👤 C Brenner
- 👤 R Kassik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:29
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/181; G08B13/187; G01; G01S; G01S17/00; G01S17/02; G01S17/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
109 words
An intrusion detection system for discriminating against targets smaller than a predetermined size comprising: means for projecting two relatively closely spaced and substantially parallel radiation beams from a source means into an area to be surveyed and being adapted to reflect radiation back to the source when an object enters the beam pathway, the spacing of said radiation beams being greater than said predetermined size, means for pulsing said radiation beams alternately at a specified rate and means at said source for detecting reflections from objects struck by said beams and means for distinguishing between reflections from one of said beams and successive reflections from both of said beams.
Claim 2
Dependent Claim
109 words
An intrusion detection system for discriminating against targets smaller than a predetermined size comprising: means for projecting two relatively closely spaced and substantially parallel radiation beams from a source means into an area to be surveyed and being adapted to reflect radiation back to the source when an object enters the beam pathway, the spacing of said radiation beams being greater than said predetermined size, means for pulsing said radiation beams alternately at a specified rate and means at said source for detecting reflections from objects struck by said beams and means for distinguishing between reflections from one of said beams and successive reflections from both of said beams.
Claim 3
Dependent Claim
15 words
The intrusion detecting system according to claim 1 wherein the beams are of infrared radiation.
Claim 4
Dependent Claim
32 words
The intrusion detecting system according to claim 1 wherein each of said beams is essentially non-divergent in one direction and substantially divergent in a direction at right angles to said one direction.
Claim 5
Independent Claim
78 words
The method of reducing the false alarm rate of an intrusion detection system comprising: transmitting alternately pulsed closely spaced-substantially parallel radiation beams which cause reflections to be returned from an object entering the field of either one or both of said beams, the spacing of said radiation beams being greater than a predetermined value, detecting the return of reflected radiation and, distinguishing between the detection of a reflection return from one beam and successive returns from both beams.
Claim 6
Independent Claim
78 words
The method of reducing the false alarm rate of an intrusion detection system comprising: transmitting alternately pulsed closely spaced-substantially parallel radiation beams which cause reflections to be returned from an object entering the field of either one or both of said beams, the spacing of said radiation beams being greater than a predetermined value, detecting the return of reflected radiation and, distinguishing between the detection of a reflection return from one beam and successive returns from both beams.
Claim 7
Dependent Claim
13 words
The method according to claim 4 wherein the beams are of infrared radiation.
Claim 8
Dependent Claim
24 words
The method according to claim 4 wherein the spacing between said means is less than the width of the object intended to be detected.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |