Method and device for localizing transponders

• US 20060012475A1
• Filed: 07/19/2005
• Published: 01/19/2006
• Est. Priority Date: 07/19/2004
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Wagner, Dieter, Froitzheim, Herbert, Munch, Matthias
• Granted Patent: US 7,482,921 B2
• Time in Patent Office: Days
• US Class Current: 340/539.230
• CPC Class Codes: B60C 23/007 having multiple wheels arranged side by side
• CPC Class Codes: B60C 23/0416 allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right
• CPC Class Codes: B60C 23/045 Means for detecting electromagnetic field changes being not part of the signal transmission per se, e.g. strength, direction, propagation or masking
• CPC Class Codes: G01S 13/75 using transponders powered from received waves, e.g. using passive transponders , or using passive reflectors

Abstract

The device and the method enable the localization of transponders, particularly in motor vehicles. A determination of the distance of different transponders from the base station is made possible by evaluating the different request signals and response signals received and also the physical variables contained therein, such as signal level, charging time, and signal propagation delay. As a result of the relative determination of the different distances of the transponders from a base station, it is for example possible to determine the position of wheels of a motor vehicle. This means savings in terms of tire electronics, which require a separate power supply and are technically more complicated and more expensive to use than transponders.

Claims

1. A device for localizing transponders, comprising:

a first transponder disposed at a first position in an object and configured to provide a first response signal;

a second transponder disposed at a second position, different from the first position, in the object and configured to provide a second response signal;

a base station having;

a transmit/receive device for transmitting a request signal to said first and second transponders and for receiving the first and second response signals in response to the request signal;

an evaluation device for evaluating the first and second response signal, for comparing the evaluated response signals, and for determining a distance from the base station to said first and second transponders.

2. The device according to claim 1, wherein said second transponder is one of a plurality of transponders each configured to provide a response signal in response to the request signal.

3. The device according to claim 1, wherein said evaluation device includes a sorting device for determining a sequence of distances of said transponders from said base station.

4. The device according to claim 3, wherein at least one of the following is true:

each of said transponders comprises at least one measuring device for performing a level measurement of the request signal and a transmit device for returning a measured level as a response signal or as part of a response signal to said base station;

said base station comprises at least one measuring device for performing a level measurement of the response signal from a respective said transponder.

5. The device according to claim 1, wherein each of said transponders comprises at least one first measuring device for performing a level measurement of the request signal and a transmit device for returning a measured level as a response signal or as part of a response signal to said base station, and/or said base station comprises at least one second measuring device for performing a level measurement of the response signal from a respective said transponder.

6. The device according to claim 5, wherein said evaluation device includes a sorting device for determining a sequence of distances of said transponders from said base station, and said sorting device is configured to use the level measurement values to determine a sequence of the distances of said transponders from said base station by sorting the level measurement values according to size values thereof such that a sorting corresponds to the distance sequence of said transponders relative to said base station.

7. The device according to claim 5, wherein at least one of said transponders includes at least one third measuring device for measuring a period of time from when said base station starts supplying power to said transponder until a predefined charging limit is reached, and a transmit device for sending back a value for the measured time period as a response signal or as part of the response signal to said base station, and/or said base station comprises at least one fourth measuring device for measuring a period of time between sending off the request signal to said transponders and receiving the corresponding response signals from said transponders.

8. The device according to claim 1, wherein at least one of the following is true:

each of said transponders includes a measuring device for measuring a period of time from when said base station starts supplying power to said transponder until a predefined charging limit is reached, and a transmit device for returning a value for the measured time period as a response signal or as part of the response signal to said base station; and

said base station includes a measuring device for measuring a period of time between transmitting the request signal to said transponders and receiving the corresponding response signals from said transponders.

9. The device according to claim 8, wherein said evaluation device includes a sorting device for determining a sequence of distances of said transponders from said base station, and said sorting device is configured to use the measured time periods to determine a sequence of the distances of said transponders from said base station by sorting the measured time periods according to size such that the sorting corresponds to the distance sequence of said transponders relative to said base station.

10. The device according to claim 1, wherein said transponders are configured to provide the response signal with an identifier characteristic of the respective said transponder.

11. The device according to claim 1, wherein said transponders and said base station are mounted to a motor vehicle.

12. A method of localizing transponders, which comprises the following steps:

(a) sending of a request signal from a base station;

(b) responding with at least one first response signal by at least one first transponder in response to the request signal;

(c) responding with at least one second response signal by at least one second transponder, disposed at a different position from the first responder, in response to the request signal;

(d) evaluating and comparing the at least two response signals received by the base station; and

(e) determining a distance of the transponders from the base station.

13. The method according to claim 12, which comprises localizing transponders in a motor vehicle.

14. The method according to claim 12, which comprises using an addressed request signal in method step, then transmitting a further addressed request signal by a base station after method step and before method step, with the further addressed request signal having different addressing compared with the addressed request signal in method step.

15. The method according to claim 12, which comprises carrying out at least one of the following steps:

measuring, with at least one transponder, levels of the request signal and sending back a measured level as a response signal to the base station; and

measuring, with the base station, levels of each response signal received from the transponders.

16. The method according to claim 15, which comprises using, with the base station, measured levels to determine a sequence of distances of the transponders from the base station by sorting level measurement values according to a size thereof such that the sorting corresponds to the distance sequence of the transponders from the base station.

17. The method according to claim 12, which comprises carrying out at least one of the following steps:

measuring, with at least one transponder, a period of time from when the base station starts supplying power until a predefined charging limit is reached for a charging capacitor in the transponder, and sending the measured period of time as a response signal back to the base station; and

measuring, with the base station, a period of time between sending a request signal to the transponders and receiving the corresponding response signals from the transponders.

18. The method according to claim 17, which comprises using the measured time periods in the base station to determine a sequence of the distances of the transponders from the base station by sorting the measured time periods according to a value thereof such that the sorting corresponds to a distance sequence of the transponders from the base station.