Methods and systems for tracking RFID devices

• US 8,120,486 B2
• Filed: 06/10/2008
• Issued: 02/21/2012
• Est. Priority Date: 06/10/2008
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Rinkes, Charles
• Primary Examiner(s): Tweel, Jr., John A
• Application Number:
  US12/136,578
• Publication Number:
  US 20090303047A1
• Time in Patent Office: 1,351 Days
• Field of Search: 340/572.1, 340/572.4, 340/5.1, 340/10.1, 235/375
• US Class Current: 340/572.1
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00

Abstract

Methods, systems, and apparatuses for tracking and monitoring tagged objects in an RFID environment is described. By varying RFID reader antenna output power levels and detecting RFID devices in the vicinity, data about position and orientation of the RFID devices can be gathered. This gathered data is used to correlate with pre-stored data about RFID devices'"'"' position and orientation. Such a correlation then can be used to infer data about neighboring RFID devices based upon data stored in the database. Such an inferential technique also results in a faster analysis of position and orientation data of RFID devices, and also leads to faster tracking of RFID enabled devices. Unnecessary reads and high power operations of the RFID reader are also avoided.

Claims

1. A system for tracking movement of employees and/or inventory, comprising:

an RFID (Radio Frequency Identification) reader including;

a power control module configured to modify the output power of the RFID reader for each read cycle in a set of read cycle;

reader circuitry configured to perform the set of read cycle according to the output power levels determined by the power control module; and

a location/orientation module coupled to the power control module and the reader circuitry, the location/orientation module configured to compare data obtained by the reader circuitry during each read cycle and the associated power level of the read cycle to determine location and orientation information for an RFID enabled device.

2. The system of claim 1, further comprising:

a database configured to store an output power level for each performed read cycle and the data obtained by the reader circuitry during each read cycle.

3. The system of claim 2, wherein the location/orientation module is further configured to compare historical data stored in the database for the RFID enabled device to develop a view of movement of the RFID enabled device.

4. The system of claim 2, wherein the database is coupled to the location/orientation module.

5. The system of claim 1, wherein the location/orientation module is external to the RFID reader.

14. The system of claim 1, wherein the location/orientation module is configured to consider a type of antenna associated with the RFID reader and a resulting antenna pattern in determining the location and orientation information.

15. The system of claim 5, further comprising:

one or more additional RFID readers communicatively coupled to the location/orientation module, wherein the location/orientation module is configured to correlate data from the RFID reader and the one or more additional RFID readers for determining the location and orientation information.

6. A method for tracking movement of employees and/or inventory using an RFID (Radio Frequency Identification) reader, comprising:

performing a series of read cycles including;

setting an output power level of the RFID reader to a predetermined value for the read cycle being performed,

performing a read of a tag population;

for each read cycle, storing the output power used during the read cycle and tag identification data obtained during the read cycle;

comparing the data for each read cycle to determine the location and orientation of an RFID device.

7. The method of claim 6, wherein setting an output level of the RFID reader includes:

setting the output level of the RFID reader to a predetermined value based on a location/orientation tracking algorithm.

8. The method of claim 6, wherein storing the output power further comprises:

storing a time stamp associated with the read cycle.

9. The method of claim 8, further comprising:

comparing historical data for the RFID reader over a pre-defined time period to develop a view of movement of the RFID device during the time period.

16. The method of claim 6, further comprising:

considering a type of antenna associated with the RFID reader and a resulting antenna pattern in determining the location and orientation information.

10. A computer program product for tracking movement of employees and/or inventory using an RFID (Radio Frequency Identification) reader comprising a computer useable medium having a computer program logic recorded thereon for controlling at least one processor, the computer program logic comprising:

computer program code means for performing a series of read cycles including;

code for setting an output power level of the RFID reader to a predetermined value for the read cycle being performed,

code for performing a read of a tag population;

code for storing the output power used during the read cycle and tag identification data obtained during the read cycle, for each read cycle;

code for comparing the data for each read cycle to determine the location and orientation of an RFID device.

11. The computer program product of claim 10, wherein said code for setting an output level of the RFID reader includes:

code for setting the output level of the RFID reader to a predetermined value based on a location/orientation tracking algorithm.

12. The computer program product of claim 10, wherein said code for storing the output power further comprises:

code for storing a time stamp associated with the read cycle.

13. The computer program product of claim 12, comprising:

code for comparing historical data for the RFID reader over a pre-defined time period to develop a view of movement of the RFID device during the time period.

17. The computer program product of claim 12, wherein the computer program logic further comprising:

code for considering a type of antenna associated with the RFID reader and a resulting antenna pattern in determining the location and orientation information.