Abstract: An RF roadway toll collection system uses an upstream reader to communicate with a vehicle borne transponder carrying a Smart Card to calculate the toll and debit the Smart Card balance in the amount of the toll payment required. A transaction manager is notified of the toll payment from the upstream reader and notifies a downstream reader of the vehicle identification and payment status. The downstream reader confirms the vehicle identification and payment status and signals if the toll has been paid.

Abstract: An RF roadway toll collection system uses an upstream reader to communicate with a vehicle borne transponder carrying a Smart Card to calculate the toll and debit the Smart Card balance in the amount of the toll payment required. A transaction manager is notified of the toll payment from the upstream reader and notifies a downstream reader of the vehicle identification and payment status. The downstream reader confirms the vehicle identification and payment status and signals if the toll has been paid.

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.

Abstract: In order to locate a transponder in a roadway there are first and second antenna arrays at spaced locations. Each array is associated with a switching control which causes the array beam to step through a series of beams. The signal developed in each beam is converted to a digital result. The strongest beam from each array may be determined and the location of the transponder at the intersection of the two strongest beams.