UTILIZATION OF MOTION AND SPATIAL IDENTIFICATION IN MOBILE RFID INTERROGATOR

• US 20090207024A1
• Filed: 02/13/2009
• Published: 08/20/2009
• Est. Priority Date: 02/14/2008
• Status: Active Grant

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Schatz, Steven V., Spiess, Gary, Anderson, Maury, Ternes, Thaddeus, Leland, Hunter
• Granted Patent: US 8,237,563 B2
• Time in Patent Office: Days
• US Class Current: 340/572.100
• 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 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions

Abstract

A system and method of using motion or spatial identification technology with a mobile RFID reader to detect whether an RFID tag is part of a forklift load or other ambulatory space includes determining if a tag is within a defined space or if a tag is in motion relative to a mobile RFID reader. The system and method determines whether a particular RFID tag is part of a forklift load/space, has been added to or removed, is an extraneous tag, etc.

Claims

1. A system for identifying a radio frequency identification (RFID) tag within a defined zone, comprising:

an RFID reader configured to scan for an RFID tag within a read zone of the RFID reader, wherein the read zone at least partially overlaps with the defined zone, and wherein the defined zone is at a location near one or more antennas of the RFID reader;

a sensor component configured to provide data to at least assist in determining positional data of the RFID tag relative to the RFID reader;

a database storing the positional data and limits of the defined zone; and

,

a processor communicatively coupled to the RFID reader, the sensor component, and the database, wherein the processor is configured to

compare the positional data from the sensor component with the defined zone limits to determine whether the RFID tag is within the defined zone, and

store the determination in the database.

2. The system of claim 1 wherein the RFID reader is secured or removably secured to a vehicle, and wherein the read zone is movable with respect to the vehicle.

3. The system of claim 1 wherein the sensor component is an accelerometer or gyroscope.

4. The system of claim 1 wherein the defined zone is a load space of a forklift truck, and wherein the sensor component is configured to determine a position of the RFID tag.

5. The system of claim 1 wherein the sensor component uses spatial identification technology.

6. The system of claim 1 wherein the sensor component includes two or more RF antennas that have a known separation for determining a location of the RFID tag.

7. The system of claim 1 wherein the sensor component includes logic for determining a distance between the RFID reader and the RFID tag based upon a received signal strength.

8. The system of claim 1 wherein the processor is further configured to determine a phase between received signals from the RFID tag and to determine whether the RFID tag is in motion relative to the RFID reader based on a change in phase.

9. The system of claim 1 wherein the processor is further configured to determine whether the RFID tag is in motion relative to the RFID reader based on backscatter modulation.

10. A system for identifying an RFID tag within a movable load space, comprising:

an RFID reader configured;

to scan for an RFID tag within a read zone of the RFID reader and

to determine a distance and an angle between the RFID reader and the RFID tag, wherein the read zone at least partially overlaps with the movable load space, and the movable load space is near the RFID reader;

a data store storing the distance and the angle and limits of the movable load space;

a processor communicatively coupled to the RFID reader and the data store, wherein the processor is configured to;

compare the distance and the angle between the RFID reader and the RFID tag with the load space limits to determine whether the RFID tag is within the movable load space; and

store the determination in the database.

11. The system of claim 10 wherein the load space moves with a forklift truck, and further wherein the RFID reader is secured or removably secured to the forklift truck.

12. The system of claim 10 wherein determining a distance and an angle between the RFID reader and the RFID tag comprises using wireless backscatter modulation.

13. The system of claim 10 wherein determining a distance and an angle between the RFID reader and the RFID tag comprises using multiple RF antennas having known separations to triangulate a position of the RFID tag.

14. The system of claim 10 wherein determining a distance and an angle between the RFID reader and the RFID tag comprises using received signal strength and logic to determine a distance between the RFID reader and the RFID tag.

15. A system for identifying an RFID tag within a defined zone, comprising:

an RFID reader configured to read an RFID tag;

means, coupled to the RFID reader, for determining positional data of the RFID tag; and

,

means, coupled to the means for determining positional data, for determining whether the RFID tag is within a defined space based at least in part on the positional data determined from the means for determining positional data.

16. A system for distinguishing an RFID tag within a movable load space from at least one extraneous tag, the system comprising:

an RFID tag detector configured to scan for a first RFID tag within a detection zone of the RFID detector, wherein the detection zone at least partially overlaps with the load space;

a first sensor configured to monitor movement of the RFID detector;

a second sensor configured to monitor movement of the first RFID tag;

a processor communicatively coupled to the RFID detector, the first sensor, and the second sensor, wherein the processor is configured to

compare movement of the first RFID tag relative to movement of the RFID detector, and.

determine whether the first RFID tag is in the load space, is not in the load space, has been added to the load space, has been removed from the load space, or is an extraneous tag based upon the movement of the first RFID tag within the read zone.

17. The system of claim 16 wherein the load space moves with a forklift truck, and further wherein the RFID reader is secured or removably secured to the forklift truck.

18. The system of claim 16 wherein the first sensor receives a signal from a speedometer or other instrument of a vehicle carrying the load.

19. The system of claim 17 wherein the first sensor is configured to detect a predetermined movement profile corresponding to movement of the forklift truck.

20. The system of claim 16 wherein the second sensor uses spatial identification technology.

21. The system of claim 16 wherein the second sensor uses wireless backscatter modulation.

22. The system of claim 16 wherein the second sensor uses phase angle measurements.

23. A method of identifying an RFID tag within a movable and defined zone, the method comprising:

determining a position of the RFID tag;

comparing limits of the defined zone with the determined position of the RFID tag, wherein the defined zone moves relative to a set location; and

,

determining whether the RFID tag is within the defined zone.

24. The system of claim 23 wherein determining a position of the RFID tag comprises using spatial identification technology.

25. The system of claim 23 wherein determining a position of the RFID tag comprises using backscatter modulation.

26. A method of distinguishing an RFID tag within a load from an extraneous tag, comprising:

monitoring movement of an RFID reader;

reading a first RFID tag;

monitoring movement of the first RFID tag within a read zone of the RFID reader; and

,

determining whether the first RFID tag is part of the load, is not part of the load, has been added to the load, has been removed from the load, or is an extraneous tag based upon movement of the first RFID tag within the read zone.

27. The method of claim 26, further comprising performing a measurement of a distance between the RFID tag and the RFID reader.

28. The method of claim 26 wherein monitoring movement of the first RFID tag comprises measuring a phase angle change of a response of the first RFID tag.

29. The method of claim 26 wherein monitoring movement of an RFID reader comprises detecting a predetermined movement profile of the RFID reader.

30. A method of determining motion of an RFID tag, comprising:

determining a first set of values for I and Q from an RFID tag read;

calculating a first phase angle from the RFID tag read using the first set of values for I and Q;

determining a second set of values for I and Q from reading of the RFID tag;

measuring a second phase angle using the second set of values for I and Q;

calculating a phase angle change from the first phase angle and the second phase angle; and

,

converting the phase angle change to distance traveled based upon a frequency of the RFID tag response.

31. The method of claim 30, wherein determining a first set of values for I and Q from an RFID tag read comprises taking a root mean square of several first sets of values for I and Q.