US4187501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic intruder detection system
Assignee: United States Department of the Army
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Filing: 1977-10-07
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Granted: 1980-02-05
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Expires: 1997-10-07
Abstract
Abstract An electronic detection system for detecting intruders employs a transmission line as a sensing element. The transmission line is positioned about the perimeter of the area to be protected. An antenna applies pulsed RF energy to the line. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques.
Inventors
- 👤 Reinhard G. Olesch
- 👤 Otto E. Rittenbach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:04
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/02; G08B13/10; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/52; G01S13/56; G01S15/00; G01S15/02; G01S15/04
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
86 words
An electronic intrusion detection system, which comprises: a transmission line; means for launching radio frequency energy onto one end of said line, said launching means comprising a radio-frequency generator, means for phase-modulating the output of said radio-frequency generator with a pseudo-random code, and means for pulse-modulating the output of said phase-modulating means; the intrusion of a target into a defined region of space about said line causing a return echo; and means for detecting said return echo thereby to detect the presence of said intruding target.
Claim 2
Dependent Claim
86 words
An electronic intrusion detection system, which comprises: a transmission line; means for launching radio frequency energy onto one end of said line, said launching means comprising a radio-frequency generator, means for phase-modulating the output of said radio-frequency generator with a pseudo-random code, and means for pulse-modulating the output of said phase-modulating means; the intrusion of a target into a defined region of space about said line causing a return echo; and means for detecting said return echo thereby to detect the presence of said intruding target.
Claim 3
Dependent Claim
32 words
The detection system according to claim 1 further comprising: non-conducting means for suspending said line a predetermined distance above the ground; and means for maintaining said line under tension to minimize sag.
Claim 4
Dependent Claim
16 words
The detection system according to claim 2 further including a ground plane for said transmission line.
Claim 5
Dependent Claim
51 words
The system according to claim 1 wherein to minimize false alarms caused by perturbations in the relatively high field proximate said line, said transmission line comprises a Goubau Line having a central conductor of radius r, and an outer, non-conductive shell of radius r 2 , r 2 >>r 1 .
Claim 6
Dependent Claim
27 words
The system according to claim 1 wherein said launching means further comprises: a horn concentric with said line for launching said pulsed radio-frequency energy onto said line.
Claim 7
Dependent Claim
86 words
The system according to claim 1 wherein said detecting means comprises: a mixer having an input connected to the output of said phase-modulating means, said mixer producing in the presence of a return echo a Doppler signal having an amplitude and frequency proportional to the magnitude and velocity of the intruding target, respectively; a video amplifier connected to the output of said mixer; and a plurality of box-car range-gate filters connected to the output of said video amplifier for determining the range of the intruding target.
Claim 8
Dependent Claim
19 words
The system according to claim 1 wherein the output of said radio-frequency generator lies between 200 and 450 MHz.
Claim 9
Dependent Claim
21 words
The system according to claim 7 wherein said radio-frequency signal is pulsed to a rate of from 20 to 30 KHZ.
Claim 10
Dependent Claim
31 words
The detection system according to claim 1 wherein said transmission line comprises a Goubau Line, including a horn concentric with said line for launching said pulsed radio-frequency energy onto said line.
Claim 11
Dependent Claim
16 words
The detection system according to claim 1 further comprising a ground plane for said transmission line.
Claim 12
Dependent Claim
73 words
The detection system according to claim 1, wherein said launching means includes: a radio-frequency amplifier connected to the output of said pulse-modulating means; a circulator connected to the output of said amplifier; a horn connected to said circulator and concentric with said line for launching said pulse radio-frequency energy; wherein said detecting means includes a radio-frequency amplifier coupled to said circulator, and said detecting means also includes demodulating means and range gate means.
Claim 13
Independent Claim
79 words
A method of detecting the presence of an intruder in a protected area, which comprises the steps of: generating an RF signal which is phase modulated with a pseudo-random code and then pulse modulated; launching said RF signal along a transmission line proximate the perimeter of the area to be protected; and detecting the presence of said intruder by detecting the return echo created by the perturbation that said intruder induces in the electromagnetic field about said transmission line.
Claim 14
Independent Claim
79 words
A method of detecting the presence of an intruder in a protected area, which comprises the steps of: generating an RF signal which is phase modulated with a pseudo-random code and then pulse modulated; launching said RF signal along a transmission line proximate the perimeter of the area to be protected; and detecting the presence of said intruder by detecting the return echo created by the perturbation that said intruder induces in the electromagnetic field about said transmission line.
Claim 15
Dependent Claim
38 words
The method according to claim 12 including the further step of: fixing the location of said intruder along said line by measuring the time interval required for the transmission of said return echo back towards the launching location.
Claim 16
Dependent Claim
107 words
A range-gated line-sensor, which comprises: a transmission line; means for launching radio frequency energy onto one end of said line, the intrusion of a target into a defined region of space about said line causing a return echo; and means for detecting said return echo thereby to detect the presence of said intruding target; wherein to minimize false alarms caused by perturbations in the relatively high field proximate said line, said transmission line comprises a Goubau line with surface means to prevent intruding objects from approaching closer than a minimum radius from the center of said transmission line, said minimum radius being at least approximately 7.5 centimeters.
Claim 17
Dependent Claim
107 words
A range-gated line-sensor, which comprises: a transmission line; means for launching radio frequency energy onto one end of said line, the intrusion of a target into a defined region of space about said line causing a return echo; and means for detecting said return echo thereby to detect the presence of said intruding target; wherein to minimize false alarms caused by perturbations in the relatively high field proximate said line, said transmission line comprises a Goubau line with surface means to prevent intruding objects from approaching closer than a minimum radius from the center of said transmission line, said minimum radius being at least approximately 7.5 centimeters.
Claim 18
Dependent Claim
39 words
The apparatus according to claim 14, wherein said transmission line has a central conductor of radius r with a thin dielectric coating, and said surface means comprises the outer surface of an outer, non-conductive shell of said minimum radius.
Claim 19
Dependent Claim
28 words
The apparatus according to claim 15, wherein said non-conductive shell has electrical properties such that the field of said central conductor with a thin dielectric coating is retained.
Claim 20
Dependent Claim
34 words
The apparatus according to claim 14, wherein the output of said radio-frequency generator lies between 150 and 450 MHz, and said radio-frequency signal is pulsed to a rate of from 20 to 30 KHz.
Claim 21
Dependent Claim
13 words
The apparatus according to claim 14 wherein said radio frequency energy is coded.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-04 | 1983-08-06 | 1984-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-04 | 1987-08-06 | 1988-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-04 | 1991-08-06 | 1992-02-05 | $7700.00 | Window Closed / Lapsed |