Moving object high-accuracy position locating method and system
First Claim
1. In a roadway system having transponders spaced along the roadway outside the intended track for traveling vehicles, each transponder transmitting a reply signal in response to a vehicle originated interrogation signal, a method of determining a vehicle'"'"'s position along the roadway, comprising:
- (a) transmitting the vehicle originated interrogation signal at an unknown angle at least partially transverse to the vehicle'"'"'s direction of travel towards the transponders;
(b) receiving the reply signal in response to the vehicle originated interrogation signal, said reply signal identifying the position of the transponder;
(c) measuring a time difference between transmission of the vehicle originated interrogation signal and receipt of each corresponding reply signal;
(d) determining a distance between the vehicle and at least one of the responding transponders from the measured time differences; and
(e) determining the position of the vehicle along the roadway using a selected triangulation method based on the distance between the vehicle and at least one responding transponder and on the position of the transponder as identified by its reply signal.
1 Assignment
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Accused Products
Abstract
In an automated roadway system having transponders or data-stations spaced at known positions along the roadway, a vehicle mounted system determines the position of a vehicle moving along the roadway. A vehicle borne transmitter transmits a spread spectrum transmit signal which is pseudo (PN) encoded. The transmitted signal is received by the transponder which emits a reply signal back to a vehicle borne receiver. The receiver also receives a second signal which may be a reply signal from the same transponder or a reply signal from an adjacent transponder. The system then measures a time difference between transmission of the vehicle originated interrogation signal and receipt of its corresponding reply signal to determine the distance between the vehicle and the transponder or reflector. Based on the determined distances, the positions of the transponders and the distance that the vehicle has traveled during its communications, the position of a vehicle is determined using triangulation methods. The interrogation signals may be spread spectrum signals that are pseudo-random (PN) encoded. When the signal is detected by a receiver in the transponder or in the vehicle receiver, the PN code is synchronized to the incoming signal to accomplish maximum correlation. The phase delay between the transmitted PN code and received PN code is used to determine the distances between the vehicle and the transponder. The periodically located transponders produce a reply signal including a PN code and embedded data which represents the transponder identification and its position, or other data which is desirable to transmit between the transponder and the vehicle traveling the roadway.
80 Citations
28 Claims
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1. In a roadway system having transponders spaced along the roadway outside the intended track for traveling vehicles, each transponder transmitting a reply signal in response to a vehicle originated interrogation signal, a method of determining a vehicle'"'"'s position along the roadway, comprising:
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(a) transmitting the vehicle originated interrogation signal at an unknown angle at least partially transverse to the vehicle'"'"'s direction of travel towards the transponders; (b) receiving the reply signal in response to the vehicle originated interrogation signal, said reply signal identifying the position of the transponder; (c) measuring a time difference between transmission of the vehicle originated interrogation signal and receipt of each corresponding reply signal; (d) determining a distance between the vehicle and at least one of the responding transponders from the measured time differences; and (e) determining the position of the vehicle along the roadway using a selected triangulation method based on the distance between the vehicle and at least one responding transponder and on the position of the transponder as identified by its reply signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a roadway system having transponders spaced at known positions along the roadway outside the intended track for traveling vehicles, each transponder transmitting a reply signal in response to a vehicle originated interrogation signal, a system for determining a vehicle'"'"'s position along the roadway, comprising:
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emission means for transmitting the vehicle originated interrogation signal at an unknown angle at least partially transverse to the vehicle'"'"'s direction of travel towards the transponders; reception means for receiving the at least one reply signal in response to the vehicle originated interrogation signal, said reply signal identifying the position of the transponder; comparison means for measuring a time difference between transmission of the vehicle originated interrogation signal and receipt of each corresponding reply signal; distance valuation means for determining the distance between the vehicle and at least one of the responding transponders from the measured time differences; and position locating means for determining the position of the vehicle along the roadway using a selected triangulation method and the distances determined by the distance valuation means. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. In a roadway system having transponders spaced at known positions along the roadway outside the intended track for traveling vehicles, each transponder transmitting a reply signal in response to a vehicle originated interrogation signal, a system for determining a vehicle'"'"'s position along the roadway, comprising:
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a vehicle mounted transmitter that transmits at least one vehicle originated interrogation signal at least partially transverse to the vehicle'"'"'s direction of travel at an unknown angle toward the transponders; a vehicle mounted receiver that receives the reply signal in response to the vehicle originated interrogation signal from the at least one transmitting transponder, said reply signal identifying the position of the transponder; a comparator circuit that measures a time difference between transmission of each vehicle originated interrogation signal by the transmitter and receipt of each corresponding reply signal by the receiver; and a distance measurement circuit that determines the distance between the vehicle and the at least one responding transponder and uses a selected triangulation method to determine the position of the vehicle on the roadway. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A system for determining a position of a vehicle along a roadway by communicating with a ground-side system having a data-station at a known position along the roadway outside the intended track for traveling vehicles, comprising:
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a transmitter that transmits an interrogating signal in a direction at least partially transverse to the vehicle'"'"'s direction of travel to the data-station; a receiver that receives a reply signal from the data-station, said reply signal identifying the position of the transponder; a time measuring device that measures a delay time between transmission of the interrogating signal and receipt of the signal to determine a distance between the vehicle and the data-station; and a triangulation calculating device that determines the vehicle'"'"'s position based on the distance between the vehicle and the data station at two time instants and on the position of the data-station as identified by its reply signal. - View Dependent Claims (22, 23, 24)
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25. A system for determining a position of a vehicle along a roadway by communicating with a ground-side system having data-stations spaced at known position along the roadway outside the intended track for traveling vehicles, comprising:
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a transmitter that transmits an interrogating signal in a direction at least partially transverse to the vehicle'"'"'s direction of travel to two of the data-stations; a receiver that receives a reply signal from each of the two data-stations, said reply signals identifying the position of the transponder; a time measuring device that measures a delay time between the interrogating signal and the reply signal to determine a distance between the vehicle and the two data-stations; and a triangulation calculating device that determines the vehicle'"'"'s position based on the positions of the two data-stations as identified by their reply signals and of the distance between the vehicle and the two data stations. - View Dependent Claims (26, 27, 28)
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Specification