Abstract: A system and method for conducting dynamic RF-link margin tests in an electronic toll collection for non-stationary vehicles travelling up to highway speed. The system maintains a list of candidate transponders and, during the course of a normal toll collection, if a transponder is on the list then the system schedules a margin test for a later handshake in the capture zone. At a location at or near the peak margin test the system conducts a margin test during one or more of the reader-transponder handshakes. The attenuation may be dynamically controlled by the system using a variable attenuator in the RF path from the reader RF module to the antenna. Distributing the margin measurement over multiple passes of a vehicle through the capture zone provides for a highway speed method of measuring link margin.

Abstract: A system and method for conducting dynamic RF-link margin tests in an electronic toll collection for non-stationary vehicles travelling up to highway speed. The system maintains a list of candidate transponders and, during the course of a normal toll collection, if a transponder is on the list then the system schedules a margin test for a later handshake in the capture zone. At a location at or near the peak margin test the system conducts a margin test during one or more of the reader-transponder handshakes. The attenuation may be dynamically controlled by the system using a variable attenuator in the RF path from the reader RF module to the antenna. Distributing the margin measurement over multiple passes of a vehicle through the capture zone provides for a highway speed method of measuring link margin.

Abstract: An electronic toll collection system wherein the reader includes a switching network and a plurality of transceivers operating under the control of a controller. The reader further includes failure detection circuitry for determining whether any of the transceivers have failed based upon the RF outputs of the transceivers. If the controller determines that a transceiver has failed, then it alters the switching pattern such that the switching network excludes the failed transceiver from being connected to the antennas. The reader thereby provides for adaptive RF channel assignment, as the particular transceiver used to excite a particular antenna may be dynamically altered, and the provision of at least two transceivers in the reader ensures transceiver redundancy.

Abstract: An electronic toll collection system wherein the reader includes a switching network and a plurality of transceivers operating under the control of a controller. The reader further includes failure detection circuitry for determining whether any of the transceivers have failed based upon the RF outputs of the transceivers. If the controller determines that a transceiver has failed, then it alters the switching pattern such that the switching network excludes the failed transceiver from being connected to the antennas. The reader thereby provides for adaptive RF channel assignment, as the particular transceiver used to excite a particular antenna may be dynamically altered, and the provision of at least two transceivers in the reader ensures transceiver redundancy.

Abstract: A method and system for adaptively allocating bandwidth in an electronic toll collection system. The system includes a reader that adapts the scanning time allocated to specific antennas based upon the traffic conditions. Those antennas that process a higher volume of traffic receive a greater allocation of the scanning time. In some embodiments, the determination as to when to allocate additional time to an antenna may be based upon whether or not a transponder is currently in the coverage zone for the antenna.

Abstract: A dual mode transponder for engaging in RF communications with a roadside reader from a vehicle. The transponder includes an antenna, an electronic toll collection (ETC) component, and an external interface. The ETC component implements a pre-defined ETC communications protocol to detect and interpret received signals and generate response signals when operating in an ETC mode. The ETC component also includes a bypass port. The external interface is coupled to the bypass port and has an external port for receiving input signals. The ETC component includes a bypass module for receiving a bypass instruction and entering a bypass mode. In the bypass mode the ETC component refrains from implementing the ETC communications protocol. Instead, the ETC component transmits the input signals relayed from the external interface to the ETC component to the reader.

Abstract: An electronic toll collection system with dynamically adjusted timing for operation of one or more subsystems. The timing is dynamically adjusted based upon the prevailing traffic speed for the roadway. The roadway traffic speed is determined based upon direct measurements of traffic speed by external equipment or based upon a variable correlated with traffic speed. The variable may include the average number of handshakes per transponder over an estimation period. The subsystem may include a vehicle position determination system, an enforcement system, a loop detection system, or other such subsystems.

Abstract: An electronic toll collection system wherein the reader includes a switching network and a plurality of transceivers operating under the control of a controller. The reader further includes failure detection circuitry for determining whether any of the transceivers have failed based upon the RF outputs of the transceivers. If the controller determines that a transceiver has failed, then it alters the switching pattern such that the switching network excludes the failed transceiver from being connected to the antennas. The reader thereby provides for adaptive RF channel assignment, as the particular transceiver used to excite a particular antenna may be dynamically altered, and the provision of at least two transceivers in the reader ensures transceiver redundancy.

Abstract: An electronic toll collection system that includes a reader with internal monitoring circuitry. The reader includes a controller and transceiver, which is connected to an antenna, wherein the transceiver sends outgoing RF signals to the antenna and receives incoming RF signals from the antenna. The reader includes transceiver monitor circuitry for monitoring the characteristics of the RF signals to assess transceiver performance. The transceiver monitor circuitry provides a result signal to the controller. The controller may adjust the operation of the transceiver through adjustments to an adjustable element based upon the measurement signals. The controller may also send measurement information to a remote computer and receive instructions from the remote computer, thereby enabling remote monitoring and adjustment of the electronic toll collection system.

Abstract: A method and system for adaptively allocating bandwidth in an electronic toll collection system. The system includes a reader that adapts the scanning time allocated to specific antennas based upon the traffic conditions. Those antennas that process a higher volume of traffic receive a greater allocation of the scanning time. In some embodiments, the determination as to when to allocate additional time to an antenna may be based upon whether or not a transponder is currently in the coverage zone for the antenna.

Abstract: An electronic toll collection system with dynamically adjusted timing for operation of one or more subsystems. The timing is dynamically adjusted based upon the prevailing traffic speed for the roadway. The roadway traffic speed is determined based upon direct measurements of traffic speed by external equipment or based upon a variable correlated with traffic speed. The variable may include the average number of handshakes per transponder over an estimation period. The subsystem may include a vehicle position determination system, an enforcement system, a loop detection system, or other such subsystems.

Abstract: A dual mode transponder for engaging in RF communications with a roadside reader from a vehicle. The transponder includes an antenna, an electronic toll collection (ETC) component, and an external interface. The ETC component implements a pre-defined ETC communications protocol to detect and interpret received signals and generate response signals when operating in an ETC mode. The ETC component also includes a bypass port. The external interface is coupled to the bypass port and has an external port for receiving input signals. The ETC component includes a bypass module for receiving a bypass instruction and entering a bypass mode. In the bypass mode the ETC component refrains from implementing the ETC communications protocol. Instead, the ETC component transmits the input signals relayed from the external interface to the ETC component to the reader.

Abstract: Methods and systems for obtaining vehicle emissions data from on-board vehicle information systems under on-road or open-road conditions. The vehicle may be equipped with a transponder for relaying emissions data to a reader. The reader includes antennas defining a communications zone within a roadway. The transponder and reader are capable of engaging in RF communications as the vehicle-mounted transponder traverses the communications zone.