VEHICLE LANE DISCRIMINATION IN AN ELECTRONIC TOLL COLLECTION SYSTEM

• US 20090184847A1
• Filed: 01/22/2009
• Published: 07/23/2009
• Est. Priority Date: 01/23/2008
• Status: Active Grant

• Current Assignee: Mark IV IVHS, Inc. (Datax Handelsgmbh)
• Original Assignee: Mark IV IVHS, Inc. (Datax Handelsgmbh)
• Inventors: Lafferty, Robert, Kohli, Japjeev
• Granted Patent: US 8,228,205 B2
• Time in Patent Office: Days
• US Class Current: 340/989
• 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

Abstract

A vehicle position determination system for determining the position of a moving vehicle in a multi-lane roadway. Two or more roadway antennas each periodically transmit an identifier that is associated with and unique to the antenna to a transponder located in the moving vehicle. As the moving vehicle passes through the coverage zone of the antennas, the transponder counts the number of times that it receives each unique identifier and reports this information to a roadside controller. Based on this information, the roadside controller can determine a probable location of the moving vehicle. The vehicle location information can be provided to an imaging system to discriminate between transponder and non-transponder equipped vehicles.

Claims

1. A vehicle position determination system for determining a position of a moving vehicle having a transponder in a multi-lane roadway, the transponder being configured to transmit a probable lane response signal which is based on the number of instances the transponder has received a transmission from one or more communication sources, the vehicle determination system comprising:

two or more roadway antennas for receiving the probable lane response signal from the transponder, the roadway antennas having partially overlapped coverage zones, each roadway antenna having a unique identifier associated therewith; and

a controller configured to cause each roadway antenna to periodically transmit its unique identifier.

2. The vehicle position determination system claimed in claim 1 further comprising a lane determination module for determining a likely position of the vehicle based on the probable lane response signal received from the transponder.

3. The vehicle position determination system claimed in claim 2 wherein the probable lane response signal comprises information indicating the number of times that each unique identifier has been received by the transponder and the lane determination module determines the likely position of the vehicle by determining which unique identifier was received the greatest amount of times during a sampling period.

4. The vehicle position determination system claimed in claim 1 wherein all of the coverage zones are substantially aligned side by side along an axis that is orthogonal to the direction of travel.

5. The vehicle position determination system claimed in claim 4 wherein all of the coverage zones have approximately similar elliptical shapes with the major axes there being substantially linearly co-aligned and extending in a direction orthogonal to the travel path of the vehicle.

6. The vehicle position determination system claimed in claim 1 wherein all of the coverage zones are of approximately the same size and shape.

7. The vehicle position determination system claimed in claim 1 wherein the lane determination module determines the probable location of the vehicle by comparing the ratio of unique identifiers received by the transponder during a sampling period to predetermined values that are associated with different possible transponder locations.

8. A transponder for a vehicle position determination system for tracking the position of a moving vehicle in a multi-lane roadway, the vehicle positioning system having at least two or more roadway antennas having partially overlapped coverage areas, each roadway antenna having a unique identifier associated therewith, each roadway antenna periodically transmitting its unique identifier, the transponder comprising:

a transponder antenna for receiving the unique identifier from at least one roadway antenna and transmitting a probable lane response signal to at least one roadway antenna;

memory for storing at least one counter, each counter being associated with one of the identifiers; and

a controller configured to increment the counter associated with one of the identifiers in response to the receipt of that identifier by the transponder antenna;

wherein the controller is configured to cause the transponder antenna to transmit the probable lane response signal to the roadway antennas, wherein the probable lane response signal is based on an accumulated value in each counter.

9. The transponder claimed in claim 8, wherein the probable lane response signal includes the accumulated value in each counter.

10. The transponder claimed in claim 8, wherein the probable lane response signal includes a transponder ID code that is unique to the transponder.

11. The transponder claimed in claim 8, wherein the controller is configured to determine which unique identifier is associated with the counter with the greatest number of accumulated counts and wherein the probable lane response signal identifies the unique identifier determined by the controller.

12. A method of determining a position of a moving vehicle having a transponder in a multi-lane roadway, the multi-lane roadway having two or more roadway antennas having partially overlapped coverage zones, each roadway antenna having a unique identifier associated therewith, the method comprising the steps of:

receiving from any one of the roadway antennas an RF trigger signal and its associated unique identifier;

incrementing a counter associated with the unique identifier in response to the receipt thereof;

generating a probable lane response signal based upon the value in the counter associated with each unique identifier; and

transmitting the probable lane response signal to at least one of the roadway antennas.

13. The method of claim 12 wherein the step of determining includes identifying which unique identifier has the highest number of counts.

14. The method of claim 12 further comprising the step of calculating a probable lane location of the vehicle based on the probable response signal received by the roadway antenna.