RFID material tracking method and apparatus

• US 7,808,367 B2
• Filed: 08/28/2002
• Issued: 10/05/2010
• Est. Priority Date: 08/09/1999
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Round Rock Research LLC
• Inventors: Moore, Scott E.
• Primary Examiner(s): Zimmerman; Brian
• Assistant Examiner(s): Nguyen; Nam V
• Application Number:
  US10/230,045
• Publication Number:
  US 20030001726A1
• Time in Patent Office: 2,960 Days
• Field of Search: 340/10.3, 340/825.49, 340 101- 102, 340 1031- 1032, 340/10.4, 340/10.42, 340/825.73, 340/10.51, 340/568.1, 340/572.1, 341/33, 235/376, 235/385
• US Class Current: 340/10.3
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00

Abstract

A method and apparatus for tracking items automatically is described. A passive RFID (Radio Frequency IDentification) tag is used with a material tracking system capable of real-time pinpoint location and identification of thousands of items in production and storage areas. Passive RFID tags are attached to the item to be tracked, remote sensing antennas are placed at each remote location to be monitored, interrogators with several antenna inputs are connected to the sensing antennas to multiplex the antenna signals, and a host computer communicates with the interrogators to determine item locations to an exacting measure.

Claims

1. A method of detecting a presence or absence of an identification tag, comprising:

providing one sensing antenna positioned at a storage location remote from an interrogator, the sensing antenna coupled to the interrogator;

exciting by the interrogator the sensing antenna to interrogate, the sensing antenna being separate from the identification tag;

decoding a detected signal in the interrogator, the detected signal responsive to the exciting of the sensing antenna and generated from the identification tag; and

storing information indicative of the presence or absence of the identification tag based on the detected signal, including storing timing information related to the identification tag.

2. The method of claim 1, wherein the exciting of the sensing antenna comprises exciting a tuned tank circuit with a square wave power signal, the tuned tank circuit including the sensing antenna.

3. The method of claim 2, wherein the exciting of the tuned tank circuit includes providing a signal through a first inductor to a driver to the tuned tank circuit, the driver coupled to ground by a second inductor, wherein the first inductor and the second inductor are used to control rise and fall times of the driver.

4. The method of claim 1, wherein the detected signal includes identification tag data.

5. The method of claim 1, wherein the storing of the information indicative of the presence or absence of an identification tag includes storing the information in a database coupled to a plurality of interrogators.

6. The method of claim 1, wherein the storing of the information indicative of the presence or absence of the identification tag includes storing a serial number.

7. The method of claim 1, wherein the storing of the information indicative of the presence or absence of the identification tag includes storing the information in a processor having on board memory.

8. The method of claim 1, wherein the storing of the information indicative of the presence or absence of the identification tag includes storing the information in a processor for subsequent communication to a host computer.

9. The method of claim 1, further comprising communicating the information to a host computer wirelessly.

10. The method of claim 1, further comprising communicating the information to a host computer using an ETHERNET protocol.

11. A method of detecting a presence or absence of a plurality of identification tags, comprising:

for each location of a plurality of locations near a plurality of storage spaces configured to store objects to which the identification tags are attached, wherein a plurality of sensing antennas are disposed at the plurality of locations respectively,

providing a sensing antenna disposed at the location, the sensing antenna coupled to a remote interrogator;

exciting the sensing antenna to interrogate an identification tag in vicinity of the sensing antenna, the sensing antenna being separate from the identification tag; and

based on whether a signal from the identification tag is detected and decoded via the sensing antenna, storing information indicating a presence or absence an object to which the identification tag is attached, wherein the information includes timing information related to the identification tag.

12. The method of claim 11, wherein the method further includes removing excitation from the sensing antenna prior to exciting a sensing antenna disposed at a separate location.

13. The method of claim 11, wherein the exciting the sensing antenna includes exciting a tuned tank circuit with a square wave power signal, the tuned tank circuit including the sensing antenna, the tuned tank circuit being local to the sensing antenna and remote to the interrogator.

14. The method of claim 13, wherein the exciting of the tuned tank circuit includes providing a signal through a first inductor to a driver to the tuned tank circuit, the driver coupled to ground by a second inductor, wherein the first inductor and the second inductor are used to control rise and fall times of the driver.

15. The method of claim 11, further comprising rectifying the signal with a diode.

16. The method of claim 11, further comprising extracting identification tag data from the signal.

17. The method of claim 11, wherein the storing includes storing information indicative of the presence or absence of the object at a storage space associated with the location.

18. The method of claim 11, wherein the storing includes storing the information in a database coupled to a plurality of interrogators.

19. The method of claim 11, wherein the information comprises a serial number.

20. The method of claim 11, wherein the storing includes storing the information in a processor having on board memory.

21. The method of claim 20, further comprising communicating the information from the processor to a host computer.

22. A tangible computer readable medium encoded with a computer program to cause a computer to perform a method of detecting a presence or absence of a plurality of identification tags, the method comprising:

for each location of a plurality of locations near a plurality of storage spaces configured to store objects to which the identification tags are attached, wherein a plurality of sensing antennas are disposed at the plurality of locations respectively,

providing a sensing antenna disposed at the location, the sensing antenna coupled to a remote interrogator;

causing exciting of the sensing antenna to interrogate an identification tag in vicinity of the sensing antenna, the sensing antenna being separate from the identification tag; and

based on whether a signal from the identification tag is detected and decoded via the sensing antenna, storing information indicative of a presence or absence an object to which the identification tag is attached, wherein the information indicative of the presence or absence of the object includes information related to arrival or departure of the object.

23. The machine-readable medium of claim 22, wherein excitation is removed from the sensing antenna prior to exciting a separate sensing antenna using the interrogator.

24. The machine-readable medium of claim 22, wherein the sensing antenna is excited with a square wave power signal.

25. The machine-readable medium of claim 22, wherein the sensing antenna is excited via a signal provided through a first inductor to a driver to a tuned tank circuit including the sensing antenna, the driver coupled to ground by a second inductor, wherein the first inductor and the second inductor control rise and fall times of the driver.

26. The machine-readable medium of claim 22, wherein the signal is detected via rectifying the signal with a diode.

27. The machine-readable medium of claim 22, wherein the signal is decoded to extract identification tag data.

28. The machine-readable medium of claim 22, wherein the information indicative of the presence or absence of the object includes timing information.

29. The machine-readable medium of claim 28, wherein the information indicative of the presence or absence of the object is stored in a database.

30. The machine-readable medium of claim 28, wherein the information indicative of the presence or absence of the object includes a serial number.

31. The machine-readable medium of claim 28, wherein the information indicative of the presence or absence of the object is stored in a processor having on board memory.

32. The machine-readable medium of claim 28, wherein the information indicative of the presence or absence of the object is stored in a processor for subsequent communication to a host computer.

33. A method to detect a presence of an object, the method comprising:

providing one sensing antenna at a location, the sensing antenna coupled to a radio frequency (RF) communications apparatus;

exciting, by the RF communications apparatus, the sensing antenna to wirelessly communicate with an RF device, the RF device physically associated with the object and storing an identification code, the sensing antenna being separate from the RF device;

decoding a detected signal in the RF communications apparatus, the detected signal responsive to the exciting of the sensing antenna and generated from the RF device physically associated with the object; and

storing information indicative of the presence of the object based at least in part on the detected signal, including storing timing information related to the object.

34. The method of claim 33, wherein the sensing antenna is being positioned at the location remote from the RF communications apparatus.

35. The method of claim 33, wherein the information indicative of the presence of the object indicates the presence of the object in vicinity of the location.

36. The method of claim 33, wherein the detected signal includes identification tag data.

37. The method of claim 36, wherein the identification tag data comprises a serial number.

38. The method of claim 36, wherein the identification tag data comprises the identification code.

39. The method of claim 33, wherein the RF communications apparatus comprises an interrogator.

40. The method of claim 39, wherein the storing of the information indicative of the presence of the object includes storing the information in a database coupled to a plurality of interrogators.

41. The method of claim 33, wherein the information indicative of the presence of the object includes information related to arrival or departure of the object.

42. A method to detect a presence of a plurality of objects, the method comprising:

providing a sensing antenna at each location of a plurality of locations, the sensing antenna connected to a respective radio frequency (RF) communications apparatus;

exciting, by the respective RF communications apparatus, the sensing antenna to wirelessly communicate with a RF device in vicinity of the sensing antenna, the RF device storing an identification code and being physically associated with a respective object, the sensing antenna being separate from the RF device; and

based on a signal from the RF device, detected and decoded via the sensing antenna, storing information indicating a presence of the object with which the RF device is physically associated, wherein the information includes timing information related to the object.

43. The method of claim 42, wherein the plurality of locations are near a plurality of storage spaces configured to store the plurality of objects with which respective RF devices are physically associated.

44. The method of claim 42, wherein the sensing antenna is provided at the location remote to the RF communications apparatus.

45. The method of claim 42, further comprising extracting identification tag data from the signal.

46. The method of claim 45, wherein the identification tag data comprises a serial number.

47. The method of claim 42, further comprising extracting the identification code from the signal.

48. The method of claim 42, wherein the information indicating the presence of the object indicates the presence of the object in vicinity of the location.

49. The method of claim 42, wherein the information indicating the presence of the object indicates the presence of the object at a storage space associated with the location.

50. The method of claim 42, wherein the respective RF communications apparatus comprises an interrogator.

51. The method of claim 50, wherein the storing includes storing the information in a database coupled to a plurality of interrogators.

52. The method of claim 42, wherein the information indicating the presence of the object includes information related to arrival or departure of the object.

53. A system to detect a presence of a plurality of objects, the system comprising:

a plurality of radio frequency (RF) communications apparatuses;

a plurality of sensing antennas positioned at a plurality of locations respectively, each sensing antenna of the sensing antennas coupled to and excited by one of the RF communications apparatuses to wirelessly communicate with a RF device in vicinity of the sensing antenna, the RF device storing an identification code and being physically associated with a respective object, the sensing antenna being separate from the RF device; and

a data storage device to store, based on a signal from the RF device detected and decoded via the sensing antenna, information indicating a presence of the object with which the RF device is physically associated, wherein the information includes timing information related to the object.

54. The system of claim 53, wherein the plurality of locations are near a plurality of storage spaces configured to store the plurality of objects with which respective RF devices are physically associated.

55. The system of claim 53, wherein each of the RF communications apparatuses is configured to extract identification tag data from signals from RF devices physically associated with the objects.

56. The system of claim 55, wherein the identification tag data comprises serial number.

57. The system of claim 55, wherein the identification tag data comprises identification code.

58. The system of claim 53, wherein each of the RF communications apparatuses comprises an interrogator.

59. The system of claim 58, wherein the data storage device is coupled to a plurality of interrogators.

60. The system of claim 53, wherein the information indicating the presence of the object includes information related to arrival or departure of the object.