Method of assigning and deducing the location of articles detected by multiple RFID antennae

• US 8,339,265 B2
• Filed: 04/25/2011
• Issued: 12/25/2012
• Est. Priority Date: 01/09/2002
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Inventors: Campero, Richard J., Bauer, Donald G., Rasband, Paul B., Spedden, Richard H., Jones, Matthew A.
• Primary Examiner(s): Tweel, Jr., John A
• Application Number:
  US13/093,081
• Publication Number:
  US 20110199211A1
• Time in Patent Office: 610 Days
• Field of Search: 340/572.7, 340/572.1, 340/10.1, 340/10.2, 340/572.4, 340/568.1, 340/539.1
• US Class Current: 340/572.7
• 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 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: G07G 1/0045 with a code reader for reading of an identifying code of the article to be registered, e.g. barcode reader or radio-frequency identity [RFID] reader
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00
• CPC Class Codes: G08B 13/2474 Antenna or antenna activator geometry, arrangement or layout loop antennae H01Q1/22
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

In accordance with preferred embodiments or the invention, a method (and corresponding apparatus) is provided for deducing the location of one or more items or objects to be monitored. In exemplary embodiments, the method (and corresponding apparatus) is implemented in RFID (radio frequency identification) applications (e.g., reading RFID tags at 13.56 MHz and approximately 900 MHz) by deducing the location of an item associated with a unique RFID tag in one or more areas of detection covered by multiple RFID reader antennae.

Claims

1. A method of determining a location of an item, the method comprising the steps of:

designating first and second detection zones respectively associated with first and second detectors, wherein the first detection zone overlaps at least an area of second detection zone;

designating the overlap area as a virtual detection zone;

detecting the presence of an item in the virtual detection zone when the item is detected by both the first and second detectors;

assigning a first percentage of the item to the first detection zone; and

assigning a second percentage of the item to the second detection zone.

2. The method of claim 1, wherein said detecting steps detects the presence of an item in the virtual detection zone after the first detector detects the presence of the item at a first time and the second detector detects the presence of an item at a second time.

3. The method of claim 1, wherein said detecting steps detect the presence of an item in the virtual detection zone by both the first and second detectors at the same time.

4. The method of claim 1, further comprising adjusting a size of the virtual detection zone by changing power supplied to at least one of the first and second detectors.

5. The method of claim 4, wherein the first and second detectors are RFID read antennae and said adjusting step comprises increasing the size of the virtual detection zone by increasing the power of at least one of the first RFID antenna and the second RFID antenna.

6. The method of claim 4, wherein said adjusting step comprises of decreasing the size of the virtual detection zone by decreasing the power of at least one of the first RFID antenna and the second RFID antenna.

8. The method of claim 1, further comprising associating the item with an RFID tag detectable by the first and second detectors.

9. The method of claim 8, further comprising assigning a unique identification number to the RFID tag selected from the group consisting of a manufacturer number, a stock keeping unit number, and a serial number.

10. The method of claim 9, further comprising:

reporting the detection of the item using the unique identification number when the item is detected by both the first and second detectors, wherein the reporting is performed only once.

7. A method of determining a location of an item, the method comprising the steps of:

designating first and second detection zones respectively associated with first and second detectors, wherein the first detection zone overlaps at least an area of second detection zone;

designating the overlap area as a virtual detection zone;

detecting the presence of an item in the virtual detection zone when the item is detected by both the first and second detectors;

adjusting a size of the virtual detection zone by changing power supplied to at least one of the first and second detectors;

wherein said adjusting step further comprises reducing the power of the first detector until the item is not detected in the virtual zone; and

resolving the location of the item wherein the item is assigned to the detection zone where it is detected.

11. A system for reading a plurality of items comprising RFID tags, the system comprising:

a plurality of RFID reader antennae capable of detecting the RFID tags; and

a plurality of RFID readers coupled to the plurality of RFID reader antennae for detecting items with a first RFID reader antenna and at least a second RFID reader antenna; and

a controller for identifying items detected by the first RFID reader antenna and at least a second RFID reader antenna and determining the location of the items;

wherein the location of the items is assigned according to the proportion of RFID tags detected by the first RFID reader antenna compared to the proportion of RFID tags detected by the second RFID reader antenna.

12. The system of claim 11, wherein the location of the items detected by both the first RFID reader antenna and the at least a second RFID reader antenna is determined to be in proximity to the first RFID reader antenna and the at least a second RFID reader antenna.

13. The system of claim 12, wherein the location of the items detected by both the first RFID reader antenna and the at least a second RFID antenna is determined to be in between the first RFID reader antenna and the at least a second RFID reader antenna.

14. A system for determining the location of a plurality of items comprising RFID tags, the system comprising:

a plurality of RFID reader antennae, each RFID antenna having a detection zone, wherein the detection zone of a first RFID antenna overlaps the detection zone of a second RFID antenna forming a virtual detection zone; and

at least one RFID reader coupled to the plurality of RFID reader antennae for detecting an item in the virtual detection zone when the presence of the item is detected by both the first and second RFID antennas, the at least one RFID reader for assigning a first percentage of the item to the first detection zone; and

assigning a second percentage of the item to the second detection zone.

15. A system for reading items comprising RFID tags, the system comprising:

a plurality of items each having an RFID tag and each RFID tag having a unique identification number;

a plurality of RFID reader antennae for reading the RFID tags wherein the RFID reader antennae have a first detection zone and at least a second detection zone;

at least one RFID reader for reading data from the RFID tags within the first detection zone and the at least a second detection zone; and

a controller for activating the plurality of RFID reader antennae to read the RFID tags, determining the location of items, and storing the data in a local database;

wherein the location of the items is in the first detection zone when said at least one RFID reader detects the item in at least the first predetermined number of read attempts out of a total number of read attempts.

16. The system of claim 15, wherein the location of the items is in the first detection zone or the at least a second detection zone.

17. The system of claim 15, wherein the first predetermined number of read attempts for which said at least one RFID reader determines that the item is in the first detection zone is 80% of the total number of read attempts made by said at least one RFID reader.

18. A method of determining a location of an item, the method comprising the steps of:

designating first and second detection zones respectively associated with first and second detectors, wherein the first detection zone overlaps at least an area of second detection zone;

designating the overlap area as a virtual detection zone;

detecting the presence of an item in the virtual detection zone when the item is detected by both the first and second detectors;

associating the item with an RFID tag detectable by the first and second detectors;

assigning a unique identification number to the RFID tag selected from the group consisting of a manufacturer number, a stock keeping unit number, and a serial number;

detecting the unique identification number during a first read cycle; and

detecting the unique identification number during a second read cycle, wherein the detection of the unique identification number during the second read cycle is suppressed when the second read cycle is performed less than a predetermined number of read cycles from the first read cycle.