REAL-TIME VEHICLE POSITION DETERMINATION USING COMMUNICATIONS WITH VARIABLE LATENCY

• US 20090231161A1
• Filed: 03/05/2009
• Published: 09/17/2009
• Est. Priority Date: 03/11/2008
• Status: Active Grant

• Current Assignee: Kapsch Trafficcom IVHS Incorporated (Datax Handelsgmbh)
• Original Assignee: Kapsch Trafficcom IVHS Incorporated (Datax Handelsgmbh)
• Inventors: Malarky, Alastair
• Granted Patent: US 8,384,560 B2
• Time in Patent Office: Days
• US Class Current: 340/933
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence
• CPC Class Codes: G08G 1/0175 by photographing vehicles, e.g. when violating traffic rules
• CPC Class Codes: G08G 1/127 to a central station ; Indicators in a central station

Abstract

A system and method for predicting the location of a vehicle in an electronic toll collection system employing a wide area communication protocol. The vehicle includes a transponder that sends reports regarding the position of the vehicle and the time at which the position was determined. The system includes a vehicle position predictor for estimating the future position of the vehicle within a roadway based on two or more reports of past positions and the times at which they were recorded. Speed data or other data impacting likely future position may also be reported and factored into the estimate. The estimate of future position may be used in connection with triggering enforcement measures, timing a toll transaction, integrating wide area toll communications into a legacy toll transaction system, or for other applications.

Claims

1. A method for tracking a vehicle in an electronic toll collection (ETC) system, the vehicle having a transponder configured to communicate with a roadside processor using a wide area RF communications protocol when in a coverage area of the system, the coverage area including a section of a multilane roadway through which vehicles travel, the method comprising:

receiving at least one RF signal from the transponder, the at least one RF signal containing position data and a recorded time, wherein the recorded time is a time at which the position data was recorded by the transponder; and

predicting the position of the vehicle at a future time based on the position data and the recorded time.

2. The method claimed in claim 1, wherein receiving comprises receiving a first RF signal containing first position data recorded at a first time and receiving a second RF signal containing second position data recorded at a second time, and wherein predicting comprises predicting the position of the vehicle at the future time based on the first and second position data and the first and second times.

3. The method claimed in claim 1, wherein the position data includes coordinate data and motion data, and wherein predicting comprises predicting the position of the vehicle at the future time based on the coordinate data and motion data.

4. The method claimed in claim 1, wherein the position data comprises filter state variables related to position prediction.

5. The method claimed in claim 1, further including synchronizing time at the transponder and the roadside processor.

6. The method claimed in claim 1, wherein the ETC system includes a vehicle detector defining a vehicle detection area within the roadway, and wherein predicting the position includes predicting a time at which the vehicle is likely to reach the vehicle detection line.

7. The method claimed in claim 6, wherein predicting the position further includes predicting a lane in which the vehicle is likely to be located when the vehicle is predicted to reach the vehicle detection area.

8. The method claimed in claim 7, wherein the ETC system includes roadside controller for conducting ETC transactions and correlating vehicle detection and toll transactions, and wherein the method further includes detecting a vehicle at the vehicle detection area, comparing the times at which vehicles are predicted to reach the vehicle detection line, and triggering another ETC event based on this comparison.

9. The method claimed in claim 1, wherein the ETC system includes a vehicle detector defining a vehicle detection point within the roadway and wherein predicting the position includes predicting the vehicle location and calculating the distance from the vehicle location to said detection point.

10. The method claimed in claim 9, wherein the vehicle detector is configured to define multiple vehicle detection points, with such points being generally arranged orthogonal to the roadway, and such points may be associated with individual lanes of the roadway.

11. The method claimed in claim 9 wherein the ETC system includes roadside controller for conducting ETC transactions and correlating vehicle detection and toll transactions, and wherein the method further includes detecting a vehicle at the vehicle detection point, comparing the position of the detection point with predicted positions of vehicles at the time of detection, and triggering another ETC event based on this comparison.

12. The method claimed in claim 8 where said ETC event is triggering of an enforcement system if the position of the vehicle detection does not correlate to the predicted positions of the vehicles.

13. The method claimed in claim 8 where said ETC event is triggering of an access system allowing the vehicle to proceed when a predicted vehicle position is correlated to the detection.

14. The method claimed in claim 8, wherein the ETC system tracks multiple vehicles within the coverage area and wherein comparing includes comparing the location of said detection points or area with the predictions for the multiple vehicles.

15. The method claimed in claim 2, wherein the transponder includes a position determination component and the method includes determining the first position at the first time and determining the second position at the second time.

16. The method claimed in claim 3, wherein the transponder includes a position and motion determination component and the method includes determining the coordinate data and motion data at the recorded time.

17. The method claimed in claim 1, wherein the ETC system further includes a legacy ETC system having a plurality of legacy antennas defining a narrow capture zone within the roadway and having a legacy reader, wherein the legacy ETC system employs a legacy communications protocol, and wherein predicting the position includes predicting a time at which the vehicle is likely to reach the narrow capture zone.

18. The method claimed in claim 17, wherein the ETC system further includes a roadside controller for conducting ETC toll transactions, and wherein the method includes reporting the presence of the transponder to the roadside controller at the time at which the vehicle is likely to reach the narrow capture zone.

19. An electronic toll collection (ETC) system for conducting toll transactions with a vehicle travelling in a multilane roadway, the vehicle having a transponder configured to communicate using a wide area communications protocol, the system comprising:

an RF communications unit and antenna having a coverage area encompassing a section of the multilane roadway through which the vehicles travel;

a wide area reader configured to communicate with the transponder via the RF communications unit and antenna, the wide area reader including a vehicle position predictor configured to receive at least one RF signal from the transponder, the at least one RF signal containing position data and a recorded time, wherein the recorded time is a time at which the position data was recorded by the transponder, and wherein the vehicle position predictor is configured to predict the position of the vehicle at a future time based on the position data and the recorded time; and

a roadside controller for conducting ETC transactions, wherein the roadside controller is adapted to receive data from the vehicle position predictor and to conduct an ETC transaction in relation to the vehicle.

20. The system claimed in claim 19, wherein the at least one RF signal comprises a first RF signal containing first position data recorded at a first time and a second RF signal containing second position data recorded at a second time, and wherein the vehicle position predictor is configured to predict the position of the vehicle at the future time based on the first and second position data and the first and second times.

21. The system claimed in claim 19, wherein the position data includes coordinate data and motion data, and wherein the vehicle position predictor is configured to predict the position of the vehicle at the future time based on the coordinate data and motion data.

22. The system claimed in claim 19, wherein the position data comprises filter state variables related to position prediction.

23. The system claimed in claim 19, wherein the transponder is configured to synchronize time with the wide area reader prior to transmitting the at least one RF signal.

24. The system claimed in claim 19, further including a vehicle detector defining a vehicle detection area within the roadway, and the vehicle position predictor is configured to predict a time at which the vehicle is likely to reach the vehicle detection area.

25. The system claimed in claim 24, wherein the vehicle position predictor is configured to predict a lane in which the vehicle is likely to be located when the vehicle is predicted to reach the vehicle detection line.

26. The system claimed in claim 25, further including an enforcement system, and wherein the roadside controller is further configured to correlate vehicle detection and toll transactions by comparing a position of the detected vehicle with the lane and the time at which the vehicle is predicted to reach the vehicle detection line, and wherein the roadside controller is configured to trigger the enforcement system if the position of the detected vehicle does not correlate to the predicted position of the vehicle.

27. The system claimed in claim 26, wherein the ETC system tracks multiple vehicles within the coverage area and the roadside controller is configured to compare comparing the position of the detected vehicle with predicted positions of the multiple vehicles.

28. The system claimed in claim 19, further including the transponder, and wherein the transponder includes a position determination component for determining the position data at the recorded time.

29. The system claimed in claim 19, wherein the ETC system further includes a legacy ETC system having a plurality of legacy antennas defining a narrow capture zone within the roadway and having a legacy reader, wherein the legacy ETC system employs a legacy communications protocol, and wherein the legacy reader includes a wide area handler for communicating with the wide area reader, and wherein the vehicle position predictor is configured to predict a time at which the vehicle is likely to reach the narrow capture zone.

30. The system claimed in claim 29, wherein the wide area handler is configured to report the presence of the transponder to the roadside controller at the time at which the vehicle is likely to reach the narrow capture zone.