Vehicle position determination system and method
DCFirst Claim
1. A vehicle position determination system for determining the position of a moving vehicle having a transponder, comprising:
- a first antenna positioned to receive periodic radio frequency data signals from the transponder when the transponder is moving through a first predetermined coverage zone having a width that is orthogonal to the travel path of the moving vehicle and a length that is parallel to the travel path of the moving vehicle, the length of the first coverage zone varying in a predetermined manner across the width thereof;
a second antenna positioned to receive periodic radio frequency data signals from the transponder when the transponder is moving through a second predetermined coverage zone that partially overlaps the first coverage zone and has a width that is orthogonal to the travel path of the moving vehicle and a length that is parallel to the travel path of the moving vehicle, the length of the second coverage zone varying in a predetermined manner across the width thereof; and
processing means responsive to the antennas to count the number of periodic data signals received by each of the antennas from the transponder during a time period and determine based on the count a probable location of the vehicle.
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Abstract
A vehicle position determination system for determining the position of a moving vehicle having a transponder includes a first and second antennas operable to receive periodic radio frequency data signals from the transponder when the transponder is moving through a first or second predetermined coverage zone, respectively. The first and second coverage zones partially overlap and each have a width that is orthogonal to the travel path of the moving vehicle and a length that is parallel to the travel path of the moving vehicle. A processor counts the number of periodic data signals received by each of the antennas from the transponder during a time period and determines based on the count a probable location of the vehicle. The vehicle location information can be provided to an imaging system to discriminate between transponder and non-transponder equipped vehicles.
109 Citations
20 Claims
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1. A vehicle position determination system for determining the position of a moving vehicle having a transponder, comprising:
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a first antenna positioned to receive periodic radio frequency data signals from the transponder when the transponder is moving through a first predetermined coverage zone having a width that is orthogonal to the travel path of the moving vehicle and a length that is parallel to the travel path of the moving vehicle, the length of the first coverage zone varying in a predetermined manner across the width thereof;
a second antenna positioned to receive periodic radio frequency data signals from the transponder when the transponder is moving through a second predetermined coverage zone that partially overlaps the first coverage zone and has a width that is orthogonal to the travel path of the moving vehicle and a length that is parallel to the travel path of the moving vehicle, the length of the second coverage zone varying in a predetermined manner across the width thereof; and
processing means responsive to the antennas to count the number of periodic data signals received by each of the antennas from the transponder during a time period and determine based on the count a probable location of the vehicle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A vehicle position determination system for determining the position of a moving vehicle having a transponder that transmits data signals in response to interrogation signals, comprising:
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a plurality of antennas positioned to transmit periodic radio frequency interrogation signals to a plurality of coverage zones and receive data signals transmitted by the transponder in response to the interrogation signals when the transponder is located in one or more of the coverage zones, the coverage zones (a) being substantially aligned along an axis that extends orthogonal to the. travel path of the moving vehicle with adjacent coverage zones partially overlapping each other, and (b) each having a generally known shape and size and each having a width that is orthogonal to the travel path of the moving vehicle and a length that is parallel to the travel path of the moving vehicle and which varies across the width of the coverage zone; and
processing means operatively connected to the antennas to cause the antennas to transmit the interrogation signals and to count the number of data signals received by the antennas in respect of each of the coverage zones during a time period and determine based on the count a probable location of the vehicle. - View Dependent Claims (16, 17)
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18. A method of determining the position of a moving vehicle having a transponder, comprising the steps of:
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transmitting periodic data signals from the transponder when the transponder is located within one or more of a plurality of coverage zones that are aligned along an axis that extends orthogonal to the travel path of the moving vehicle with adjacent coverage zones partially overlapping each other, the coverage zones each having a known shape and size and each having a width that is orthogonal to the travel path of the moving vehicle and a length that is parallel to the travel path of the moving vehicle and which varies across the width of the coverage zone;
counting, for a time period that commences when the transponder first enters one of the coverage zones, the data signals transmitted by the transponder in each of the coverage zones; and
determining, based on the counted data signals for each of the coverage zones a probable location of the vehicle. - View Dependent Claims (19, 20)
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Specification