US3680121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mobile locator system for metropolitan areas
Assignee: General Electric Co
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Filing: 1970-01-02
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Granted: 1972-07-25
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Expires: 1990-01-02
Abstract
Abstract A locator system is disclosed wherein the vehicle whose location is unknown transmits a short, modulated radio frequency pulse. Receiving stations about the periphery of the area being serviced phase compare the received signal with a standard time reference signal. The phase difference is used to determine the arrival time differences at the known locations of the receiving stations from which the location of the vehicle may be determined. The wavelength of the modulating signal is generally greater than the maximum distance encountered in the service area. The effects of multipath reflections are minimized by utilizing a space dispersed antenna.
Inventors
- 👤 Roy E Anderson
- 👤 Miguel A Merigo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:09
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/72; G01S5/00; G01S5/02; G01S5/06
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
83 words
A method for locating a vehicle comprising the steps of positioning at least three receiving stations about the periphery of the area in which said vehicle may be located; initiating narrow band transmission from said vehicle of a tone modulated signal, receiving said modulated signal at said receiving stations, and comparing the times of arrival of said modulated signal and a time reference signal to obtain range difference information so that the specific location of said vehicle within said area can be determined.
Claim 2
Independent Claim
83 words
A method for locating a vehicle comprising the steps of positioning at least three receiving stations about the periphery of the area in which said vehicle may be located; initiating narrow band transmission from said vehicle of a tone modulated signal, receiving said modulated signal at said receiving stations, and comparing the times of arrival of said modulated signal and a time reference signal to obtain range difference information so that the specific location of said vehicle within said area can be determined.
Claim 3
Dependent Claim
56 words
The method as set forth in claim 1 wherein said comparing step comprises receiving a locally generated television signal, deriving from said television signal said time reference signal, and comparing said derived time reference signal with said received modulated signal to obtain range difference information from which said vehicle may be specifically located within said area.
Claim 4
Dependent Claim
44 words
The method as set forth in claim 2 comprising the additional steps of performing said receiving, deriving, and comparing steps at said receiving station, and conveying said information from each receiving station to a central station where the specific vehicle location may be determined.
Claim 5
Dependent Claim
28 words
The method as set forth in claim 1 further comprising the steps of generating a time reference signal, and communicating said time reference signal to said receiving stations.
Claim 6
Dependent Claim
18 words
The method as set forth in claim 1 wherein said initiation is accomplished in response to voice request.
Claim 7
Dependent Claim
19 words
The method as set forth in claim 1 wherein said initiation is in response to an identification coded request.
Claim 8
Dependent Claim
18 words
The method as set forth in claim 1 wherein said initiation is accomplished automatically on a programmed basis.
Claim 9
Dependent Claim
36 words
The method as set forth in claim 1 wherein said initiation includes the step of modulating a carrier frequency with a signal whose modulating wavelength is longer than the largest dimension of said area being served.
Claim 10
Dependent Claim
26 words
The method as set forth in claim 1 wherein the duration of said initiated transmission is on the order of 64 cycles of the modulating signal.
Claim 11
Dependent Claim
31 words
The method as set forth in claim 1 including the step of providing a space dispersed antenna system for use with said receiving stations thereby minimizing the effects of multipath reflections.
Claim 12
Dependent Claim
18 words
The method as set forth in claim 10 wherein said providing step is performed at each receiving station.
Claim 13
Dependent Claim
22 words
The method as set forth in claim 1 including the step of determining the specific location of said vehicle within said area.
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) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |