Concept for determining the position or orientation of a transponder in an RFID system

• US 20070290846A1
• Filed: 06/07/2006
• Published: 12/20/2007
• Est. Priority Date: 06/07/2006
• Status: Abandoned Application

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Wissendheit, Uwe, Gerhaeuser, Heinz, Schilling, Meinhard, Oehler, Martin, Kuznetsova, Dina
• Application Number:
  US11/422,831
• Publication Number:
  US 20070290846A1
• Time in Patent Office: Days
• US Class Current: 340/572.1
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10128 the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device
• CPC Class Codes: H04B 17/27 for locating or positioning the transmitter
• CPC Class Codes: H04B 5/45 Transponders
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A method for determining the position or orientation of a transponder by inductive coupling in a radio system, wherein the radio system includes a transceiver having antenna means, comprising a step of generating a magnetic alternating field by means of the transceiver and the antenna means and a step of determining an association signal representing a measure of inductive coupling between the antenna means of the transceiver and the transponder, wherein a distance or orientation of the transponder to the antenna means may be associated to the inductive coupling.

Claims

1. A method for determining the position or orientation of a transponder (110) by inductive coupling in a radio system, the radio system including a transceiver (100) comprising antenna means (102), comprising the steps of:

generating a magnetic alternating field by means of the transceiver (100) and the antenna means (102); and

determining an association signal representing a measure of inductive coupling between the antenna means (102) of the transceiver (100) and the transponder (110), wherein a distance or orientation of the transponder (110) to the antenna means (102) may be associated to the inductive coupling.

2. The method according to claim 1, wherein determining the association signal takes place in the transceiver (100).

3. The method according to claims 1 or 2, wherein the transponder (110) comprises a read minimum field strength required for communication between the transponder (110) and the transceiver (100), and wherein the magnetic alternating field is generated by means of the transceiver (100) by a drive signal (S_St) for the antenna means (102), and wherein the step of determining the association signal comprises the following sub-steps:

varying the field strength of the magnetic alternating field via the drive signal (S_St); and

evaluating the drive signal (S_St) with regard to the communication between the transponder (110) and the transceiver (100) to determine the occurrence of the read minimum field strength of the magnetic alternating field at the transponder (110), wherein the drive-signal (S_St) corresponds to the association signal when the read minimum field strength occurs.

4. The method according to claims 1 or 2, wherein the transponder (110) comprises a response minimum field strength required for an energy supply of the transponder (110), and wherein the magnetic alternating field is generated by means of the transceiver (100) by a drive signal (S_St) for the antenna means (102), and wherein the step of determining the association signal comprises the following sub-steps:

varying the field strength of the magnetic alternating field via the drive signal (S_St); and

evaluating the drive signal (S_St) with regard to inductive coupling from the transponder (110) to the transceiver (100) to determine the occurrence of the response minimum field strength of the magnetic alternating field at the transponder (110), wherein the drive signal (S_St) corresponds to the association, signal when the response minimum field strength occurs.

5. The method according to claims 1 or 2, wherein the step of determining the association signal comprises the following sub-steps:

detecting the coupling effect of the transponder (110) caused by the inductive coupling between the transponder (110) and the transceiver (100) on the transceiver (100), wherein the coupling effect is a measure of the distance between the transponder (110) and the antenna means (102); and

generating the association signal based on the coupling effect detected, wherein the association signal has a direct portion (S₌) and/or and, alternating portion (S_˜

).

6. The method according to claim, 5, wherein the direct portion (S₌) of the association signal is caused by a load created by the transponder (110) and detectable in the transceiver (100).

7. The method according to claims 5 or 6, wherein the alternating portion (S_˜

) of the association signal is caused by a load modulation created by the transponder (110) and detectable in the transceiver (100).

8. The method according to claim 1, wherein determining the association signal takes place in the transponder (110).

9. The method according to claim 8, wherein an induction signal (S_Trans,Rx) is generated at antenna means (112) of the transponder (110) by the magnetic alternating field at the location of the transponder (110), and wherein the step of determining comprises the following sub-step:

determining the association signal based on the induction signal (S_Trans,Rx), wherein the association signal is transferable by means of inductive coupling from the transponder (110) to the transceiver (100).

10. The method according to claims 8 or 9, wherein in the step of determining the association signal a direct portion and/or an alternating portion of the association signal is determined.

11. The method according to claims 9 or 10, wherein the step of determining the association signal additionally comprises a step of digitalizing the induction signal.

12. The method according to one of claims 8-11, wherein when transferring the association signal, additionally the association signal may be integrated in a data transfer protocol between the transponder (110) and the transceiver (100).

13. The method according to one of the preceding claims, wherein the antenna means (102) comprises a plurality of antennas (500a-f), wherein each antenna (500a;

500b;

500c;

500d;

500e;

500f) may be driven separately and the step of determining the association signal is performable for each antenna (500a;

500b;

500c;

500d;

500e;

500f) of the plurality of antennas (500a-f).

14. The method according to claim 13, wherein a position of the transponder (110) is determined by means of the association signals of the plurality of antennas (500a-f).

15. The method according to claims 13 or 14, wherein the antennas (500a;

500b;

500c;

500d;

500e;

500f) of the plurality of antennas (500a-f) and an antenna (112) of the transponder (110) comprise coils with coil opening areas, wherein the magnetic field flows through the coil opening areas and the coil opening area of the transponder (110) is arranged in a respective fixed angle to the coil opening areas of the antenna means (102) of the transceiver (100).

16. The method according to one of claims 13-15, wherein the antennas (500a;

500b;

500c;

500d;

500e;

500f) of the antenna means (102) comprise coils having coil opening areas, wherein the magnetic field flows through the coil opening areas and the coils are arranged such that they form at least two at least approximately orthogonally arranged Helmholtz coil pairs and a transponder orientation is determined via an association signal representing a measure of inductive coupling, wherein an angle of the transponder (110) within the space spanned by the Helmholtz coil pairs may be associated to the inductive coupling.

17. The method according to one of claims 13 to 16, wherein determining a transponder orientation takes place such that the antennas (500a;

500b;

500c;

500d;

500e;

500f) of the antenna means (102) are driven simultaneously by means of drive signals of different phase positions to influence an orientation of the magnetic field within the space spanned by the antennas (500a;

500b;

500c;

500d;

500e;

500f) of the antenna means (102) and thus determine an association signal representing a measure of inductive coupling, wherein an angle of the transponder (110) within the space spanned by the antennas (500a;

500b;

500c;

500d;

500e;

500f) may be associated to the inductive coupling.

18. The method according to one of the preceding claims, comprising the steps of:

detecting the orientation of the transponder (110) with regard to the antenna means (102);

generating the magnetic alternating field based on the orientation detected so that the magnetic alternating field penetrates the transponder (110) in a predetermined angle; and

determining the distance from the transponder (110) to the antenna means (102).

19. The method according to claim 18, wherein the predetermined angle is in a range of 90°

±

30°

.

39. A computer program having a program code for performing a method according to one of claims 1 to 19 when the computer program runs on a computer and/or microcontroller.

20. A transceiver (100) in a radio system for determining the position or orientation of a transponder (110) by inductive coupling, comprising:

antenna means (102) for generating a magnetic alternating field;

means (104) for generating a drive signal (S_St) for driving the antenna means (102); and

processing means (108) formed to determine, with inductive coupling with a transponder (110), an association signal representing a measure of inductive coupling, wherein the inductive coupling may be associated to a distance or orientation of the transponder (110) to the transceiver (100).

21. The device according to claim 20, wherein the means (104) for generating the drive signal (S_St) is formed to vary the drive signal (S_St) with regard to amplitude to vary the field strength of the magnetic alternating field.

22. The device according to claims 20 or 21, wherein the transponder (110) comprises a read minimum field strength required for communication between the transponder (110) and the transceiver (100), and wherein the magnetic alternating field is generated by means of the transceiver 100 by a drive signal (S_St) for the antenna means (102), the processing means (108) further comprising:

means for varying the field strength of the magnetic alternating field via the drive signal (S_St); and

means for evaluating the drive signal (S_St) with regard to the communication between the transponder (110) and the transceiver (100) to determine the occurrence of the read minimum field strength of the magnetic alternating field at the transponder (110), wherein the drive signal (S_St) corresponds to the association signal when the read minimum field strength occurs.

23. The device according to claims 20 or 21, wherein the transponder (110) comprises a response minimum field strength required for an energy supply of the transponder (110), and wherein the magnetic alternating field is generated by means of the transceiver (100) by a drive signal (S_St) for the antenna means (102), and wherein the processing means (108) further comprises:

means for varying the field strength of the magnetic alternating field via the drive signal (S_St); and

means for evaluating the drive signal (S_St) with regard to inductive coupling from the transponder (110) to the transceiver (100) to determine the occurrence of the response minimum field strength of the magnetic alternating field at the transponder (110), wherein the drive signal (S_St) corresponds to the association signal when the response minimum field strength occurs.

24. The device according to claim 20, wherein the processing means (108) is formed to detect a coupling effect of the transponder (110) created by the inductive coupling between the transponder (110) and the transceiver (100) on the transceiver (100), wherein the coupling effect is a measure of the distance between the transponder (110) and the antenna means (102), and to generate an association signal based on the coupling effect detected, the association signal comprising a direct portion (S₌) and/or an alternating portion (S_˜

).

25. The device according to claim 21, wherein an induction signal is generated at antenna means (112) of the transponder (110) by the magnetic alternating field at the location of the transponder (110), and wherein the processing means (108) further comprises:

means for determining the association signal based on the induction signal, wherein the association signal is transferable by means of inductive coupling from the transponder (110) to the transceiver (100).

26. The device according to one of claims 20 to 25, wherein the antenna means (102) includes an antenna in the form of a coil, wherein the coil comprises a coil opening area which magnetic alternating field flows through.

27. The device according to one of claims 20 to 26, wherein the antenna means (102) comprises a plurality of antennas (500a-f) in the form of coils, wherein the coils (500a;

500b;

500c;

500d;

500e;

500f) each comprise coil opening areas which the magnetic alternating field flows through.

28. The device according to claim 27, wherein the coils (500a;

500b;

500c;

500d;

500e;

500f) of the plurality of coils are arranged to one another such that two coil opening areas are each arranged in an angle in a range of 60°

±

15°

.

29. The device according to claim 27, wherein the coils (500a;

500b;

500c;

500d;

500e;

500f) of the plurality of coils are arranged to one another such that two coil opening areas are each arranged in an angle in a range of 90°

±

15°

.

30. The device according to claim 27, wherein two mutually opposite coils each of the plurality of coils (500a-f) are arranged such that the two coils form a Helmholtz coil pair.

31. The device according to claim 29, wherein the antenna means (102) further comprises a diagonal antenna (500e) in the form of a coil comprising both an angle of 45±

10°

relative to a first coil (500a) of the approximately orthogonally arranged coils and comprising an angle of 45°

±

10°

relative to a second coil (500b) of the approximately orthogonally arranged coils.

32. The device according to one of claims 20 to 31, wherein the means (104) for generating the drive signal (S_St) for driving the antenna means is formed to drive each antenna (500a;

500b;

500c;

500d;

500e;

500f) of the plurality of antennas of the antenna means (102) in a temporally successive manner.

33. The device according to one of claims 20 to 32, wherein the means (104) for generating the drive signal (S_St) for driving the antenna means (102) is formed to drive all antennas (500a;

500b;

500c;

500d;

500e;

500f) of the plurality of antennas of the antenna means (102) simultaneously.

34. The device according to claim 33, wherein the means (104) for generating the drive signal (S_St) for driving the antenna means (102) is formed to generate drive signals of different phase positions for different antennas (500a;

500b;

500c;

500d;

500e;

500f) of the plurality of antennas of the antenna means (102).

35. A transponder (110) for determining a position or orientation comprising:

antenna means (112);

means (250) for providing an association signal (S_Trans,Tx) representing a measure of inductive coupling, wherein the inductive coupling may be associated to a distance or orientation of the transponder (110) to a transceiver (100), and wherein the association signal (S_Trans,Tx) is transferable to the transceiver (100) by means of inductive coupling.

36. The transponder according to claim 35, wherein the association signal corresponds to a rectified induction signal (S_Trans,Rx) generated at the antenna means (112) by the magnetic alternating field at the location of the transponder (110).

37. The transponder according to claims 35 or 36, wherein the means (250) for providing the association signal additionally comprises means (306) for digitalizing the induction signal (S_Trans,Rx) generated at the antenna means (112).

38. The transponder according to one of claims 35 to 37, wherein the means (250) for providing the association signal (S_Trans,Tx) further comprises means (308) for integrating the digitalized induction signal (S_Trans,Rx) induced at the antenna means (112) in a data transfer protocol to be able to transfer the association signal by means of inductive coupling to the transceiver (100).