Enhanced transponder programming in an open road toll system

1. A method for programming a transponder in a moving vehicle in a roadway, the roadway having an electronic toll collection system that includes a plurality of antennas, the plurality of antennas are mounted to a gantry spanning the roadway such that each antenna defines a coverage area, and adjacent coverage areas are distinct but partly overlap, the transponder having a memory, the method comprising:

transmitting, in a normal mode, a programming signal from one of the antennas over its coverage area to instruct the transponder to store data in its memory, the data being contained in the programming signal, wherein the transponder is to transmit a response signal after storing the data in its memory;

determining that the transponder did not store the data in its memory by determining that the response signal was not received within a predetermined time of transmission of the programming signal in the normal mode; and

based on the determination that the transponder did not store the data in its memory, selecting an antenna adjacent to said one of the antennas and transmitting the programming signal from the selected adjacent antenna over its coverage area.

2. The method of claim 1 , wherein the transmitting of the programming signal in the normal mode includes transmitting the programming signal at a first power level, and wherein the transmitting of the programming signal using the selected adjacent antenna occurs at a second power level higher than the first power level.

3. The method of claim 1 , wherein the determining that the transponder did not store the data in its memory includes transmitting the programming signal two or more times using the one of the antennas and determining after each of the two or more times that the transponder did not store the data in its memory prior to using the adjacent antenna.

4. An electronic toll collection system for programming a transponder located in a moving vehicle travelling in a roadway, the transponder having a memory, the system comprising:

a plurality of antennas mounted to a gantry spanning the roadway such that each antenna defines a coverage area that includes at least a portion of the roadway for transmitting a programming signal, wherein adjacent coverage areas are distinct but partly overlap; and

a control device connected to the antennas, the control device

to direct one of the antennas to transmit, in a normal mode, the programming signal over its coverage area to instruct the transponder to store data in its memory, the data being contained in the programming signal, wherein the transponder is to transmit a response signal after storing the data in its memory,

to determine that the transponder did not store the data in its memory by determining that the response signal was not received within a predetermined time of transmission of the programming signal in the normal mode, and,

based on the determination that the transponder did not store the data in its memory, to select an antenna adjacent to the one of the antennas and to cause the selected adjacent antenna to transmit the programming signal over its coverage area.

5. The electronic toll collection system of claim 4 , wherein in the normal mode the control device directs the one of the antennas to transmit the programming signal at a first power level, and the control device is to cause over the selected adjacent antenna to transmit the programming signal at a second power level higher than the first power level.

6. The method claimed in claim 1 , wherein the overlapping coverage areas are aligned along an axis orthogonal to a travel direction in the roadway.

7. The electronic toll collection system of claim 4 , wherein the overlapping coverage areas are aligned along an axis orthogonal to a travel direction in the roadway.

8. A method for programming a transponder in a moving vehicle in a roadway, the roadway having an electronic toll collection system that includes a plurality of antennas, the plurality of antennas are mounted to a gantry spanning the roadway such that each antenna defines a coverage area, and adjacent coverage areas are distinct but partly overlap, the transponder having a memory, the method comprising:

transmitting, in a normal mode, a programming signal from one of the antennas over its coverage area to instruct the transponder to store data in its memory, the data being contained in the programming signal;

determining that the transponder did not store the data in its memory by

transmitting a read signal from the one of the antennas to the transponder,

receiving, at the one of the antennas, a response signal from the transponder containing contents of a portion of the memory in the transponder, and

determining from the contents that the transponder did not store the data in its memory; and

based on the determination that the transponder did not store the data in its memory, selecting an antenna adjacent to the one of the antennas and transmitting the programming signal from the selected adjacent antenna over its coverage area.

9. The method of claim 8 , wherein the transmitting of the programming signal in the normal mode includes transmitting the programming signal at a first power level, and wherein the transmitting of the programming signal using the selected adjacent antenna occurs at a second power level higher than the first power level.

10. The method claimed in claim 8 , wherein the determining that the transponder did not store the data in its memory includes transmitting the programming signal two or more times using the one of the antennas and determining after each of the two or more times that the transponder did not store the data in its memory prior to using the adjacent antenna.

11. An electronic toll collection system for programming a transponder located in a moving vehicle travelling in a roadway, the transponder having a memory, the system comprising:

a plurality of antennas mounted to a gantry spanning the roadway such that each antenna defines a coverage area that includes at least a portion of the roadway for transmitting a programming signal, wherein adjacent coverage areas are distinct but partly overlap; and

a control device connected to the antennas, the control device

to direct one of the antennas to transmit, in a normal mode, a programming signal over its coverage area to instruct the transponder to store data in its memory, the data being contained in the programming signal,

to determine that the transponder did not store the data in its memory by

transmitting a read signal from the one of the antennas to the transponder,

receiving, at the one of the antennas, a response signal from the transponder containing contents of a portion of the memory in the transponder, and

determining from the contents that the transponder did not store the data in its memory, and,

based on the determination that the transponder did not store the data in its memory, to select an antenna adjacent to the one of the antennas and to cause the selected adjacent antenna to transmit the programming signal over its coverage area.

12. The electronic toll collection system of claim 11 , wherein in the normal mode the control device directs the one of the antennas to transmit the programming signal at a first power level, and the control device is to cause the selected adjacent antenna to transmit the programming signal at a second power level higher than the first power level.

13. The electronic toll collection system of claim 11 , wherein the control device is to determine that the transponder did not store the data in its memory by transmitting the programming signal two or more times using the one of the antennas and determining after each transmission that the transponder did not store the data in its memory prior to using the adjacent antenna.

14. A method for programming a transponder in a moving vehicle in a roadway, the roadway having an electronic toll collection system that includes a plurality of antennas, the plurality of antennas are mounted to a gantry spanning the roadway such that each antenna defines a coverage area, and adjacent coverage areas are distinct but partly overlap, the transponder having a memory, the method comprising:

transmitting, in a normal mode, a programming signal from one of the antennas over its coverage area to instruct the transponder to store data in its memory, the data being contained in the programming signal;

determining that the transponder did not store the data in its memory by

transmitting a read signal from the one of the antennas to the transponder, to which the transponder is adapted to respond, and

determining that no response is received to the read signal within a predetermined time of transmission of the read signal; and

based on the determination that the transponder did not store the data in its memory, selecting an antenna adjacent to the one of the antennas and transmitting the programming signal from the selected adjacent antenna over its coverage area.

15. The method of claim 14 , wherein the transmitting of the programming signal in the normal mode includes transmitting the programming signal at a first power level, and wherein the transmitting of the programming signal using the selected adjacent antenna occurs at a second power level higher than the first power level.

16. The method claimed in claim 14 , wherein the determining that the transponder did not store the data in its memory includes transmitting the programming signal two or more times using the one of the antennas and determining after each of the two or more times that the transponder did not store the data in its memory prior to using the adjacent antenna.

17. An electronic toll collection system for programming a transponder located in a moving vehicle travelling in a roadway, the transponder having a memory, the system comprising:

a plurality of antennas mounted to a gantry spanning the roadway such that each antenna defines a coverage area that includes at least a portion of the roadway for transmitting a programming signal, wherein adjacent coverage areas are distinct but partly overlap; and

a control device connected to the antennas, the control device

to direct one of the antennas to transmit, in a normal mode, a programming signal over its coverage area to instruct the transponder to store data in its memory, the data being contained in the programming signal,

to determine that the transponder did not store the data in its memory by

transmitting a read signal from the one of the antennas to the transponder, to which the transponder is adapted to respond, and

determining that no response is received to the read signal within a predetermined time of transmission of the read signal, and,

based on the determination that the transponder did not store the data in its memory, to select an antenna adjacent to the one of the antennas and to transmit the programming signal from the selected adjacent antenna over its coverage area.

18. The electronic toll collection system of claim 17 , wherein in the normal mode the control device directs the one of the antennas to transmit the programming signal at a first power level, and the control device is to cause the selected adjacent antenna to transmit the programming signal at a second power level higher than the first power level.

19. The electronic toll collection system of claim 17 , wherein the control device is to determine that the transponder did not store the data in its memory by transmitting the programming signal two or more times using the one of the antennas and determining after each transmission that the transponder did not store the data in its memory prior to using said adjacent antenna.

20. A method for programming a transponder in a moving vehicle in a roadway, the roadway having an electronic toll collection system that includes a plurality of antennas, the plurality of antennas are mounted to a gantry spanning the roadway such that each antenna defines a coverage area, and adjacent coverage areas are distinct but partly overlap, the transponder having a memory, the method comprising:

transmitting, in a normal mode, a programming signal from one of the antennas over its coverage area to instruct the transponder to store data in its memory, the data being contained in the programming signal, wherein the transponder is to transmit a response signal in reply to the programming signal;

receiving the response signal and determining from the response signal that the transponder did not store the data in its memory; and

based on the determination that the transponder did not store the data in its memory, selecting an antenna adjacent to said one of the antennas and transmitting the programming signal from the selected adjacent antenna over its coverage area.

21. The method of claim 20 , wherein the transmitting of the programming signal in the normal mode includes transmitting the programming signal at a first power level, and wherein the transmitting of the programming signal using the selected adjacent antenna occurs at a second power level higher than the first power level.

22. The method claimed in claim 20 , wherein the determining that the transponder did not store the data in its memory includes transmitting the programming signal two or more times using the one of the antennas and determining after each of the two or more times that the transponder did not store the data in its memory prior to using the adjacent antenna.

23. An electronic toll collection system for programming a transponder located in a moving vehicle travelling in a roadway, the transponder having a memory, the system comprising:

a plurality of antennas mounted to a gantry spanning the roadway such that each antenna defines a coverage area that includes at least a portion of the roadway for transmitting a programming signal, wherein adjacent coverage areas are distinct but partly overlap; and

a control device connected to the antennas, the control device

to direct one of the antennas to transmit, in a normal mode, a programming signal over its coverage area to instruct the transponder to store data in its memory, the data being contained in the programming signal, wherein the transponder is to transmit a response signal in reply to the programming signal,

to receive the response signal and to determine from the response signal that the transponder did not store the data in its memory, and,

based on the determination that the transponder did not store the data in its memory, to select an antenna adjacent to the one of the antennas and to cause the selected adjacent antenna to transmit the programming signal over its coverage area.

24. The electronic toll collection system of claim 23 , wherein in the normal mode the control device directs the one of the antennas to transmit the programming signal at a first power level, and the control device is to cause the selected adjacent antenna to transmit the programming signal at a second power level higher than the first power level.

25. The electronic toll collection system of claim 23 , wherein the control device is to determine that the transponder did not store the data in its memory by transmitting the programming signal two or more times using the one of the antennas and determining after each transmission that the transponder did not store the data in its memory prior to using said adjacent antenna.