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US3772691A
Expired / Lapsed
US
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Automatic vehicle location system
Assignee: National Aeronautics and Space Administration
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Filing: 1971-10-05
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Granted: 1973-11-13
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Expires: 1991-10-05
Abstract
Abstract An automatic vehicle detection system is disclosed, in which each vehicle whose location is to be detected carries active means which interact with passive elements at each location to be identified. In one embodiment the passive means comprise a plurality of passive loops arranged in a sequence along the travel direction. Each of the loops is tuned to a chosen frequency so that the sequence of the frequencies defines the location code. As the vehicle traverses the sequence fo the loops as it passes over each loop, signals only at the frequency of the loop being passed over are coupled from a vehicle transmitter to a vehicle receiver. The frequencies of the received signals in the receiver produce outputs which together represent a code of the traversed location. In another embodiment the code location is defined by a painted pattern which reflects light to a vehicle-carried detector whose output is used to derive the code defined by the pattern.
Inventors
- 👤 G Hansen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:10
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/74; G01S13/00; G01S13/74; G01S13/75; G01S13/751; G01S13/753; G08; G08G; G08G1/00; G08G1/01; G08G1/017
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
231 words
A system for providing in a vehicle a code indicative of a location last traversed by said vehicle comprising: transmitter means in said vehicle including a transmitting loop for simultaneously transmitting unmodulated signals at N different frequencies, where N is not less than two; receiver means in said vehicle and including a receiving loop for receiving unmodulated signals at any one of said N different frequencies, said transmitting and receiving loops being aligned in a direction perpendicular to the vehicle''s travel direction; a plurality of individual passive elements spaced apart from one another and located sequentially in the direction of travel of said vehicle at each location, each passive element being tuned only to a selected one of said N frequencies, whereby as said vehicle passes over the passive element and the transmitting and receiving loops are over the passive element signals which are transmitted by said transmitting loop at the frequency corresponding to the frequency to which the element being passed over is tuned are directly coupled to and received by said receiving loop of said receiver means; and code means in said vehicle coupled to said receiver means for providing a code indicative of the location last traversed as a function of the frequencies of the signals which have been received successively by said receiver means after the vehicle passed over all of said passive elements at said location.
Claim 2
Independent Claim
231 words
A system for providing in a vehicle a code indicative of a location last traversed by said vehicle comprising: transmitter means in said vehicle including a transmitting loop for simultaneously transmitting unmodulated signals at N different frequencies, where N is not less than two; receiver means in said vehicle and including a receiving loop for receiving unmodulated signals at any one of said N different frequencies, said transmitting and receiving loops being aligned in a direction perpendicular to the vehicle''s travel direction; a plurality of individual passive elements spaced apart from one another and located sequentially in the direction of travel of said vehicle at each location, each passive element being tuned only to a selected one of said N frequencies, whereby as said vehicle passes over the passive element and the transmitting and receiving loops are over the passive element signals which are transmitted by said transmitting loop at the frequency corresponding to the frequency to which the element being passed over is tuned are directly coupled to and received by said receiving loop of said receiver means; and code means in said vehicle coupled to said receiver means for providing a code indicative of the location last traversed as a function of the frequencies of the signals which have been received successively by said receiver means after the vehicle passed over all of said passive elements at said location.
Claim 3
Dependent Claim
198 words
The system as described in claim 1 wherein N 2, the two frequencies being definable as fo and f1, and each passive element is tunable to either fo or f1 whereby when the transmitting and receiving loops are over a passive element tuned to fo, only the fo signals are directly coupled from said transmitting loop to said receiving loop, and when both the transmitting loop and receiving loop are over a passive element tuned to f1 only the f1 signals transmitted by said transmitting loop are directly coupled to said receiving loop, and said code means include a bistable element which is driven to a first state when the fo signals are received and to a second state when the f1 signals are received, and a multistage register means coupled to said bistable element for storing a first binary value when fo signals are received and said bistable element is driven to said first state and for storing a second binary value when f1 signals are received and said bistable element is driven to its second state, whereby the binary values in said register means represent the code indicative of the location last traversed by said vehicle.
Claim 4
Dependent Claim
50 words
The system as described in claim 2 wherein each of said passive elements is a loop tuned to eithEr fo or f1 having a dimension in a direction perpendicular to the vehicle''s direction of travel which is at least as great as the distance between said transmitting and receiving loops.
Claim 5
Dependent Claim
41 words
The system as described in claim 1 wherein each of said passive element is a loop having a dimension in a direction perpendicular to the vehicle''s direction of travel which is related to the distance between said transmitting and receiving loops.
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) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |