SYSTEM, METHOD AND COMPUTER PROGRAM PRODUCT FOR CALIBRATING INTERROGATOR SIGNAL STRENGTH AND/OR TAG RESPONSE RANGE SETTING

• US 20070290802A1
• Filed: 06/09/2006
• Published: 12/20/2007
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: Zest Labs, Inc.
• Original Assignee: Intelleflex Corporation
• Inventors: Batra, Naresh, Nandu, Heena
• Granted Patent: US 9,087,226 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• 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 7/10039 interrogator driven, i.e. synchronous
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A system, method and computer program product according to one embodiment are provided for calibrating an RFID interrogator. A signal is sent from an interrogator to a calibration device. A backscatter signal is received from the calibration device. The backscatter from the calibration device is analyzed. An outgoing signal strength of the interrogator is adjusted based on the analysis. In a system, method and computer program product according to another embodiment, the interrogator is set to selectively respond to tags returning a backscatter signal strength selected based on the analysis. In a system, method and computer program product according to another embodiment, comparison criteria is selected based on the analysis of the backscatter signal. An RF device is instructed to store the comparison criteria, which is then used by the RF device to selectively respond to an interrogator signal having at least a desired strength.

Claims

1. A method for calibrating an RFID interrogator, comprising:

sending a signal from an interrogator to a calibration devices;

receiving a backscatter signal from the calibration device;

analyzing the backscatter from the calibration device; and

adjusting an outgoing signal strength of the interrogator based on the analysis.

2. The method as recited in claim 1, wherein the calibration device is permanently coupled to a structure.

3. The method as recited in claim 1, wherein the calibration device is detachably coupled to a structure.

4. The method as recited in claim 1, wherein the calibration device is located at a known distance from an antenna of the interrogator.

5. The method as recited in claim 1, wherein the calibration device is coupled to a fixed power supply.

6. The method as recited in claim 1, wherein the calibration device is a semi-passive RFID tag.

7. The method as recited in claim 1, wherein the calibration device is a passive RFID tag.

8. The method as recited in claim 1, wherein results of the analysis are maintained in a table.

9. The method as recited in claim 8, wherein the results of the analysis include analysis of backscatter at differing, interrogator power levels.

10. The method as recited in claim 8, wherein the table contains historical data.

11. The method as recited in claim 1, wherein the backscatter signal is of varying strength as a result of varying a transmitting power of the outgoing signal, the analysis including analyzing the backscatter signal at each of the various transmitted power levels.

12. The method as recited in claim 1, wherein the backscatter from the calibration device is analyzed at a specified time increment.

13. The method as recited in claim 1, wherein the backscatter from the calibration device is analyzed upon detecting a change in an environmental condition.

14. A method for calibrating an RFID interrogator comprising:

sending a signal from an interrogator to a calibration device;

receiving a backscatter signal from the calibration device;

analyzing the backscatter from the calibration device; and

setting the interrogator to selectively respond to tags returning a backscatter signal strength selected based on the analysis.

15. The method as recited in claim 14, wherein the calibration device is permanently coupled to a structure.

16. The method as recited in claim 14, wherein the calibration device is detachably coupled to a structure.

17. The method as recited in claim 14, wherein the calibration device is located at a known distance from an antenna of the interrogator.

18. The method as recited in claim 14, wherein the calibration device is coupled to a fixed power supply.

19. The method as recited in claim 14, wherein the calibration device is a semi-passive RFID tag.

20. The method as recited in claim 14, wherein the calibration device is a passive RFID tag

21. The method as recited in claim 14, wherein results of the analysis are maintained in a table.

22. The method as recited in claim 21, wherein the results of the analysis include analysis of backscatter at differing interrogator power levels.

23. The method as recited in claim 21, wherein the table contains historical data.

24. The method as recited in claim 14, wherein the backscatter signal is of varying strength as a result of varying a transmitting power of the outgoing signal, the analysis including analyzing the backscatter signal at each of the various transmitted power levels.

25. The method as recited in claim 14, wherein the backscatter from the calibration device is analyzed at a specified time increment.

26. The method as recited in claim 14, wherein the backscatter from the calibration device is analyzed upon detecting a change in an environmental condition.

27. A method for setting a response comparison criteria for a Radio Frequency (RF) device, comprising:

sending a signal from an interrogator to a calibration device;

receiving a backscatter signal from the calibration device;

analyzing the backscatter from the calibration device;

selecting comparison criteria based on the analysis of the backscatter signal; and

instructing an RF device to store the comparison criteria,

wherein the comparison criteria is used by the RF device to selectively respond to an interrogator signal having at least a desired strength.

28. The method as recited in claim 27, wherein the calibration device is permanently coupled to a structure.

29. The method as recited in claim 27, wherein the calibration device is detachably coupled to a structure.

30. The method as recited in claim 27, wherein the calibration device is located at a known distance from an antenna of the interrogator.

31. The method as recited in claim 27, wherein the calibration device is coupled to a fixed power supply.

32. The method as recited in claim 27, wherein the calibration device is a semi-passive RFID tag.

33. The method as recited in claim 27, wherein the calibration device is a passive RFID tag.

34. The method as recited in claim 27, wherein results of the analysis are maintained in a table.

35. The method as recited in claim 34, wherein the results of the analysis include analysis of backscatter at differing interrogator power levels.

36. The method as recited in claim 34, wherein the table contains historical data.

37. The method as recited in claim 27, wherein the backscatter signal is of varying strength as a result of varying a transmitting power of the outgoing signal, the analysis including analyzing the backscatter signal at each of the various transmitted power levels.

38. The method as recited in claim 27, wherein the backscatter from the calibration device is analyzed at a specified time increment.

39. The method as recited in claim 27, wherein the backscatter from the calibration device is analyzed upon detecting a change in an environmental condition.

40. A Radio Frequency Identification (RFID) system, comprising:

an interrogator sending an outgoing signal; and

a calibration device backscattering the interrogator signal;

wherein the backscatter signal from the calibration device is analyzed,

wherein an outgoing signal strength of the interrogator is adjusted based on the analysis of the backscattered signal.

41. A. Radio Frequency Identification (RFID) system, comprising:

an interrogator sending an outgoing signal; and

a calibration device backscattering the interrogator signal;

wherein the backscatter from the calibration device is analyzed,

wherein the interrogator is set to selectively respond to one or more RFID tags returning a backscatter signal having at least a desired strength based on the analysis of the backscatter signal.

42. A Radio Frequency Identification (RFID) system, comprising:

an interrogator sending an outgoing signal;

a calibration device backscattering the interrogator signal; and

a plurality of RFID tags.

wherein the backscatter from the calibration device is analyzed,

wherein the RFID tags are set to selectively respond to an interrogator signal having at least a desired strength based on the analysis of the backscatter signal.

43. A computer program product comprising a computer useable medium including a computer readable program, wherein the computer readable program when executed on a computing device causes the computing device to:

send a signal from an interrogator to a calibration device;

receive a backscatter signal from the calibration device;

analyze the backscatter from the calibration device; and

adjust an outgoing signal strength of the interrogator based on the analysis.

44. A computer program product comprising a computer useable medium including a computer readable program, wherein the computer readable program when executed on a computing device causes the computer device to:

send a signal from an interrogator to a calibration device;

receive a backscatter signal from the calibration device;

analyze the backscatter from the calibration device; and

set the interrogator to selectively respond to tags returning a backscatter signal strength selected based on the analysis.

45. A computer program product comprising a computer useable medium including a computer readable program, wherein the computer readable program when executed on a computing device causes the computing device to:

send a signal from an interrogator to a calibration device;

receive a backscatter signal from the calibration device;

analyze the backscatter from the calibration devices;

select comparison criteria based on the analysis of the backscatter signals; and

instruct an RF device to store the comparison criteria;

wherein the comparison criteria is used by the RF device to selectively respond to an interrogator signal having at least a desired strength.