RF systems and methods for tracking and singulating tagged items

• US 7,525,434 B2
• Filed: 06/09/2006
• Issued: 04/28/2009
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: Zest Labs, Inc.
• Original Assignee: Intelleflex Corporation
• Inventors: Batra, Naresh
• Primary Examiner(s): Goins; Davetta W.
• Assistant Examiner(s): Labbees; Edny
• Application Number:
  US11/423,410
• Publication Number:
  US 20070285236A1
• Time in Patent Office: 1,054 Days
• Field of Search: 342/42, 342450-453, 342463-465, 342/139, 342/140, 342385-391, 235375-385, 700/45, 700/225, 340/572.1, 340/572.2, 340/572.4, 340/572.9, 340/572.3
• US Class Current: 340/572.1
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• 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

Abstract

A method for identifying an approximate location of a radio frequency tag includes scanning zones of an area in an active mode at a first power level for identifying the zone in which the tag is located, and scanning portions of the zone in which the tag is located in a passive mode at a second power level for identifying the portion of the zone in which the tag is located. An RFID system includes a plurality of RFID tags and an RFID interrogator in communication with the RFID tags.

Claims

1. A method for identifying an approximate location of a radio frequency tag, the method comprising:

scanning zones of an area in an active mode as a first power level for identifying the zone in which the tag is located;

scanning portions of the zones in which the tag is located in a passive mode at a second power level for identifying the portion of the zone in which the tag is located.

2. A method as recited in claim 1, further comprising scanning sub-zones of the zone in which the tag is located in an active mode at a third power level, the third power level being lower than the first power level.

3. A method as recited in claim 1, further comprising scanning sub-portions of the portion of the zone in which the tag is located in a passive mode at a fourth power level, the fourth power level being lower than the second power level.

4. A method as recited in claim 1, wherein the zones are individually scanned.

5. A method as recited in claim 4, wherein a single interrogator is physically moved to each zone.

6. A method as recited in claim 5, wherein the portions of the zones in which the tag is located are also scanned by the single interrogator.

7. A method as recited in claim 5, wherein each zone is defined by an effective range of the interrogator at the first power level.

8. A method as recited in claim 4, wherein each zone is scanned by an individual interrogator, wherein the portions of the zone in which the tag is located are scanned by a single interrogator.

9. A method as recited in claim 1, wherein the tag is coupled to an object, the tag storing information about the object.

10. A method as recited in claim 1 , wherein the tag is coupled to an object, the tag having a unique identifier, the identifier being correlated with information about the object in a database.

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

a plurality of RFID tags; and

an RFID interrogator in communication with the RFID tags, the RFID interrogator performing at least a portion of the scanning of method 1.

12. A method for identifying an approximate location of a radio frequency tag, the method comprising:

scanning zones of an area in an active mode at a first power level for identifying the zone in which the tag is located;

scanning sub-zones of the zone in which the tag is located in an active mode at a second power level for identifying the sub-zone in which the tag is located, the second power level being lower than the first power level;

scanning portions of the sub-zone in which the tag is located in a passive mode at a third power level for identifying the portion of the zone in which the tag is located; and

scanning sub-portions of the portion of the sub-zone in which the tag is located in a passive mode at a fourth level, the fourth power level being lower than the third power level.

13. A method as recited in claim 12, wherein the zones are individually scanned.

14. A method as recited in claim 12, wherein each zone, portion of the sub-zone, and sub-portion of the portion of the sub-zone is defined by an effective range of the interrogator at the associated power level.

15. A method as recited in claim 14, wherein a single interrogator is physically moved to each zone.

16. A method as recited in claim 15, wherein the portions of the zone in which the tag is located are also scanned by the single interrogator.

17. A method as recited in claim 14, wherein each zone is scanned by an individual interrogator, wherein the portions of the zone in which the tag is located are scanned by a single interrogator.

18. A method as recited in claim 12, wherein the tag is coupled to an object, the tag storing information about the object.

19. A method as recited in claim 12, wherein the tag is coupled to an object, the tag having a unique identifier, the identifier being correlated with information about the object in a database.

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

p1 a plurality of RFID tags; and

a plurality of RFID interrogators in communication with the plurality of RFID tags, at least one of the RFID interrogators scanning zones of an area in an active mode at a first power level for identifying the zone in which at least one of the RFID tags is located;

scanning portions of the zone in which the tag is located in a passive mode at a second power level for identifying the portion of the zone in which the tag is located.

21. A system for identifying an approximate location of a radio frequency tag, the system comprising:

an interrogator for scanning zones of an area in an active mode at a first power level for identifying the zone in which the tag is located;

wherein the interrogator also scans sub-zones of the zone in which the tag is located in an active mode at a second power level for identifying the sub-zone in which the tag is located, the second power level being lower than the first power level;

wherein the interrogator also scans portions of the sub-zone in which the tag is located in a passive mode at a third power level for identifying the portion of the zone in which the tag is located; and

wherein the interrogator also scans sub-portions of the portion of the sub-zone in which the tag is located in a passive mode at a fourth power level, the fourth power level being lower than the third power level.