RFID reader location self-discovery

• US 9,092,679 B2
• Filed: 04/12/2013
• Issued: 07/28/2015
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Walmart Apollo, LLC (WalMart Inc.)
• Original Assignee: Wal Mart Stores Inc (WalMart Inc.)
• Inventors: Jones, Nicholaus Adam, Taulbee, Alvin Scott
• Primary Examiner(s): BEE, ANDREW W.
• Application Number:
  US13/862,350
• Publication Number:
  US 20140306808A1
• Time in Patent Office: 837 Days
• Field of Search: 340/10.4, 340/10.1, 340/572.7
• US Class Current: 1/1
• CPC Class Codes: G01S 1/68 Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 5/0284 Relative positioning
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• 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 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
• CPC Class Codes: G06K 7/10099 the directional field being used for pinpointing the location of the record carrier, e.g. for finding or locating an RFID tag amongst a plurality of RFID tags, each RFID tag being associated with an object, e.g. for physically locating the RFID tagged object in a warehouse
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

A system and method of determining the location of a RFID reader is disclosed. The system comprises a first RFID reader, and at least one other RFID reader, and a processor. The RFID readers associate unique RFID tag information with at least one antenna that reads the information. The processor receives RFID data from the first RFID reader and the at least one other RFID reader and determines the location of the first RFID reader relative to the at least one other RFID reader based on the association of unique RFID tag information with at least one antenna of at least two readers.

Claims

1. A method of determining a location of an RFID reader comprising:

receiving first RFID data from a first RFID reader comprising a first plurality of antennas, wherein the first RFID data associates first tag information with each of the first plurality of antennas that reads the first tag information, wherein the first tag information uniquely identifies at least one RFID tag;

receiving second RFID data from a second RFID reader having a second plurality of antennas, wherein the second RFID data associates the first tag information with each of the second plurality of antennas that reads the first tag information; and

determining a location of the first RFID reader relative to the second RFID reader with a processor based on the associations in the first and the second RFID data.

2. The method of claim 1, further comprising:

locating the RFID readers in an overhead position.

3. The method of claim 1, further comprising:

determining the orientation of the RFID readers.

4. The method of claim 1, further comprising:

identifying each of the first plurality of antennas and each of the second plurality of antennas associated with the first tag information that uniquely identifies a first RFID tag of the at least one RFID tag.

5. The method of claim 4, further comprising:

identifying each of the first plurality of antennas and each of the second plurality of antennas associated with the first tag information that uniquely identifies a second RFID tag of the at least one RFID tag.

6. The method of claim 1, further comprising:

determining an internal boundary of the facility based on the first and second RFID data.

7. The method of claim 1, further comprising repeating the determination step over a duration of time.

8. The method of claim 1, further comprising determining properties of the at least one RFID tag uniquely identified by the first tag information.

9. The method of claim 1, further comprising determining a quantity of the at least one RFID tag uniquely identified by the first tag information.

10. The method of claim 1, further comprising determining a mix of the at least one RFID tag uniquely identified by the first tag information.

11. The method of claim 1, further comprising:

receiving third RFID data from a third RFID reader having a third plurality of antennas, wherein the third RFID data associates the first tag information with each of the third plurality of antennas that reads the first tag information; and

determining a location of the first RFID reader relative to the second RFID reader and the third RFID reader based on the associations in the first, the second, and the third RFID data.

12. A system for determining a location of a RFID reader comprising:

a first RFID reader having a first plurality of antennas configured to generate first RFID data, wherein the first RFID data associates first tag information with each of the first plurality of antennas that reads the first tag information, and wherein the first tag information uniquely identifies at least one RFID tag;

a second RFID reader having a second plurality of antennas configured to generate second RFID data, wherein the second RFID data associates the first tag information with each of the second plurality of antennas that reads the first tag information; and

a processor configured to receive the first RFID data and the second RFID data and to determine a location of the first RFID reader relative to the second RFID reader based on associations in the first RFID data and the second RFID data.

13. The system of claim 12, further comprising:

a third RFID reader having a third plurality of antennas configured to generate third RFID data, wherein the third RFID data associates the first tag information with each of the third plurality of antennas that reads the first tag information; and

wherein the processor is further configured to receive the third RFID data and to determine a location of the first RFID reader relative to the second RFID reader and the third RFID reader based on associations in the first RFID data, the second RFID data, and the third RFID data.

14. The system of claim 12, wherein the first plurality of the antennas are distributed 360°

around the first RFID reader.

15. The system of claim 12, wherein the first RFID reader arranged in an overhead position.

16. The system of claim 12, wherein the processor is further configured to determine an internal boundary of a facility based on the first RFID data and the second RFID data.

17. The system of claim 12, wherein the processor is further configured to periodically compare the first RFID data and the second RFID data.

18. The system of claim 12, wherein the processor is further configured to compare the first RFID data and the second RFID data, based on a property of the at least one RFID tag uniquely identified by the first tag information.

19. The system of claim 12, wherein the processor is further configured to compare the first RFID data and the second RFID data, based on a quantity of the at least one RFID tag uniquely identified by the first tag information.

20. The system of claim 12, wherein the processor is further configured to compare the first RFID data and the second RFID data, based on a mix of the at least one RFID tag uniquely identified by the first tag information.

21. A non-transitory computer readable medium comprising instructions configured to cause a computer processor to execute a method comprising the steps of:

receive first RFID data from a first RFID reader comprising a first plurality of antennas, wherein the first RFID data associates first tag information with each of the first plurality of antennas that reads the first tag information, wherein the first tag information uniquely identifies at least one RFID tag;

receive second RFID data from a second RFID reader having a second plurality of antennas, wherein the second RFID data associates the first tag information with each of the second plurality of antennas that reads the first tag information; and

determine a location of the first RFID reader relative to the second RFID reader with a processor based on the associations of the first RFID data and the second RFID data including where the RFID data is first tag information associated with each of a plurality of antennas included with each reader, as presented in the claimed invention.