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

• US 7,932,830 B2
• Filed: 05/06/2005
• Issued: 04/26/2011
• Est. Priority Date: 05/07/2004
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Inventors: Bauer, Donald G., Rasband, Paul B., Spedden, Richard H., Jones, Matthew A., Campero, Richard J.
• Primary Examiner(s): TWEEL JR, JOHN ALEXANDER
• Application Number:
  US11/579,637
• Publication Number:
  US 20080266092A1
• Time in Patent Office: 2,181 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: G01S 13/82 wherein continuous-type signals are transmitted
• CPC Class Codes: G06K 17/0012 with more than one selection steps, e.g. selection of a record carrier from a selected compartment of a compartmented storage storage devices for articles B65G1/0407
• 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

Abstract

In accordance with preferred embodiments of 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 deducing the location of a plurality of items, the method comprising the steps of:

designating first and second detection zones respectively associated with first and second detectors;

assigning the items to the first detection zone and the second detection zone;

designating the first detection zone and the second detection zone as related zones; and

resolving the location of an item detected in both the first detection zone and the second detection zone by assigning the detected item to the first detection zone or to the second detection zone.

2. The method of claim 1, further comprising pre-assigning items to the first or second detection zones prior to performance of said resolving step.

3. The method of claim 1, wherein an item detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 50% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

4. The method of claim 1, wherein an item detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 66% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

5. The method of claim 1, wherein an item detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 80% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

6. The method of claim 1, further comprising the step of providing a plurality of items each having an RFID tag comprising a unique identification number.

7. The method of claim 1, wherein said step of providing a plurality of items comprises selecting a unique identification number for each RFID tag from the group consisting of a manufacturer number, a stock keeping unit number, and a serial number.

8. A method of assigning the location of a plurality of items, the method comprising the steps of:

designating first and second detection zones respectively associated with first and second detectors;

comparing the number of items detected in the first detection zone and the second detection zone;

determining the number of items detected in both the first detection zone and the second detection zone; and

deducing a location of an item detected in both the first detection zone and the second detection zone based on assignment of the item to one of the first and second detection zones, wherein said deducing step comprises the step of assigning the item to one of the first and second detection zones in accordance with the proportion of the items in the first detection zone compared to the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

9. The method of claim 8, wherein the location of the items detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 50% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

10. The method of claim 8, wherein the location of the items detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 66% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

11. The method of claim 8, wherein the location of the items detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 80% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

12. The method of claim 8, wherein the location of 50% the items detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected only in the first detection zone is equal to the number of items detected in both the first and second detection zones.

13. The method of claim 8, wherein the total number of items assigned to a detection zone does not exceed a predetermined capacity for the detection zone.

14. The method of claim 8, wherein the predetermined capacity of the detection zone is determined by the area of the detection zone.

15. The method of claim 8, wherein the predetermined capacity of the detection zone is determined by the volume of the detection zone.

16. A method of assigning the location of a plurality of items, the method comprising the steps of:

designating first and at least a second detection zone respectively associated with first and at least a second RFID reader antennae;

detecting the items with an RFID reader antenna;

comparing the number of items detected in the first detection zone and the at least a second detection zone;

identifying a joint item detected in both the first detection zone and the at least a second detection zone; and

assigning a first percentage of the joint item to the first detection zone and a second percentage of the joint item to the at least a second detection zone.

17. The method of claim 16, further comprising detecting the joint item in a third detection zone.

18. The method of claim 16, wherein the first percentage of the joint item is 50% if the number of detection zones is two.

19. The method of claim 17, wherein the first percentage of the joint item is 33% if the number of detection zones is three.

20. The method of claim 16, wherein the first percentage of the joint item is 50% for the first detection zone and the second percentage of the joint item is 25% for a second detection zone.

21. The method of claim 17, where the first detection zone is adjacent to the second detection zone and the third detection zone.

22. The method of claim 17, wherein the percentage of the location is 100% for the first detection zone, 0% for the second detection zone, and 0% for the third detection zone.

23. The method of claim 22, where the first detection zone is adjacent to the second detection zone and the third detection zone.

24. A method of confirming that an item is missing, the method comprising the steps of:

providing a plurality of items wherein each item is associated with an RFID tag;

designating a detection zone associated with an RFID reader antennae;

detecting the presence of an item in the detection zone at a first time by polling the RFID reader antenna;

determining if the item is present during at least a second time, wherein if the item is not present during the at least second time, the RFID reader antenna is polled a predetermined number of times; and

confirming that the item is missing if the item is not detected after the RFID reader antenna is polled for the predetermined number of times.

25. The method of claim 24, wherein the predetermined number of times is increased if the packaging of the item interferes with the polling of the RFID antenna.

26. A method of reporting information regarding detection of at least one item that is associated with an RFID tag, the method comprising the steps of:

detecting an item during a first read cycle;

reporting information regarding detection of the item during the first read cycle;

detecting the item during subsequent read cycles; and

suppressing information regarding detection of the item during a predetermined number of subsequent read cycles.

27. The method of suppressing data as recited in claim 26, wherein said step of detecting the item during subsequent read cycles comprises the step of detecting the item during a period less than a predetermined length of time after the first read cycle;

and

wherein the step of suppressing information comprises the step of suppressing the information regarding detection of the item during the subsequent read cycles for the predetermined length of time.

28. The method of suppressing data as recited in claim 26, wherein said steps of detecting an item during a first read cycle and detecting the item during subsequent read cycles are both performed using a first reader antenna.

29. The method of suppressing data as recited in claim 26, wherein said steps of detecting an item during a first read cycle and detecting the item during subsequent read cycles are performed using a first reader antenna and second reader antenna, respectively.

30. A system for deducing 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 a first detection zone and at least a second detection zone are related zones if an item is detected in both the first detection zone and the at least a second detection zone; and

at least one RFID reader coupled to the plurality of RFID reader antennae for detecting an item wherein the location of an item detected in the related zone is assigned to the first detection zone or to the at least a second detection zone.

31. A system for assigning the location of a plurality of items comprising RFID tags, the system comprising:

a plurality of RFID reader antennae, each of the plurality of RFID antennae having a first detection zone and at least a second detection zone; and

at least one RFID reader coupled to the RFID reader antennae for determining the number of items within the first detection zone and the at least a second detection zone, wherein the number of items within the first detection zone is compared to the number of items within the second detection zone and the deduced location of the items is assigned according to the proportion of the number items in the first detection zone compared to the number of items in the at least a second detection zone.