RFID tag locationing using dynamic beacon tag association

Patent metadata

Field	Value
Publication number	US-9733335-B2
Application number	US-201414540070-A
Country	US
Kind code	B2
Filing date	Nov 13, 2014
Priority date	Nov 13, 2014
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A method and apparatus for determining the position of a RFID tag. The method includes the following: (1) measuring the position of an active device to an accuracy of better than 1.0 meter using a radio locating system to determine the position of a reference point; (2) detecting a first RF signal from a reference RFID tag near the reference point with an RF receiver in an RFID reading system; (3) detecting a second RF signal from a RFID tag of interest with the RF receiver in the RFID reading system; and (4) processing both the first RF signal and the second RF signal and relying upon at least partially the position of the reference point to determine the position of the RFID tag of interest.

First claim

What is claimed is:

1. A method for using a radio frequency identification (RFID) reading system to communicate with a reference RFID tag via a RFID communication protocol, the method comprising:
using a radio locating system to wirelessly communicate with an active device via a second protocol that is different than the RFID communication protocol used by the RFID reading system to communicate with the reference RFID tag, including measuring the position of the active device to an accuracy of better than 1.0 meter using the radio locating system to determine the position of a reference point, wherein the active device is a mobile device and the reference point is a mobile reference point;
using the RFID reading system to communicate with the reference RFID tag and a RFID tag of interest via the RFID communication protocol, including:
(i) detecting a first RF signal from the reference RFID tag with an RF receiver in the RFID reading system, the radio locating system being a type of system that is different from the RFID reading system, wherein the reference RFID tag is located essentially at the same position of the mobile reference point, with the distance between the reference RFID tag and the reference point being less than 0.2 meter, and wherein the distance between the reference RFID tag and the RF receiver in the RFID reading system is more than 3.0 meter; and
(ii) detecting a second RF signal from the RFID tag of interest with the RF receiver in the RFID reading system; and

processing both the first RF signal and the second RF signal and relying upon at least partially the position of the reference point to determine a position of the RFID tag of interest.

2. The method of claim 1 , wherein the radio locating system comprises:
a plurality of radio locating devices distributed at multiple locations.

3. The method of claim 1 , wherein said processing comprises at least one of:
processing the difference between the time stamp of the first RF signal and the time stamp of the second RF signal;
processing the difference between the received signal strength indicator (RSSI) of the first RF signal and the RSSI of the second RF signal; and
processing the difference between the phase of the first RF signal and the phase of the second RF signal.

4. The method of claim 1 , wherein said processing comprises:
processing both the first RF signal and the second RF signal to determine an offset between the position of the RFID tag of interest and the position of the reference point.

5. The method of claim 1 , wherein said measuring the position of the active device comprises at least one of:
measuring the angle of arrival of a radio signal; and
measuring the angle of departure of a radio signal.

6. The method of claim 1 , wherein said measuring the position of the active device comprises:
measuring the time of flight of a radio signal.

7. The method of claim 1 , wherein the reference RFID tag and the RFID tag of interest have substantially identical antenna design.

8. The method of claim 1 , wherein the reference RFID tag and the RFID tag of interest have substantially identical backscattering characteristics at the RF frequency of an interrogating signal from the RFID reading system.

9. The method of claim 1 , wherein both the reference RFID tag and the RFID tag of interest are passive RFID devices.

10. The method of claim 1 , wherein the active device is a mobile computing device including one of a smartphone, a tablet computer, a smart badge, and a smart watch.

11. The method of claim 1 , wherein the active device is configured to establish wireless connections with the radio locating system based upon a standard including one of BLUETOOTH™ and ZIGBEE™.

12. The method of claim 1 , further comprising:
transmitting from the active device to the radio locating system one or more digital communication packet containing the Electronic Product Code (EPC) of the reference RFID tag.

13. The method of claim 1 , wherein the active device has a media access control address (MAC address) for establishing digital communication with the radio locating system.

14. The method of claim 13 , further comprising:
transmitting from the reference RFID tag to the RFID reading system the MAC address of the active device.

15. The method of claim 1 , further comprising:
triggering beacon activity on the active device with a radio signal from one of the RFID tags including the reference RFID tag and the RFID tag of interest.

16. The method of claim 15 , further comprising:
generating said radio signal from said one of the RFID tags in response to said one of the RFID tags being interrogated by the RFID reading system.

17. The method of claim 1 , wherein the distance between the reference RFID tag and the reference point is less than 0.1 meter.

18. The method of claim 1 , wherein the distance between the reference RFID tag and the reference point is less than 0.05 meter.

19. The method of claim 1 , wherein the distance between the reference RFID tag and the reference point is less than 0.01 meter.

20. An apparatus for using with radio frequency identification (RFID) tags, the apparatus comprising:
an RFID reading system configured to communicate with a reference RFID tag and a RFID tag of interest via a RFID communication protocol;
a radio locating system configured to wirelessly communicate with an active device via a second protocol that is different than the RFID communication protocol used by the RFID reading system to communicate with the reference RFID tag and the RFID tag of interest, wherein the radio locating system is configured to measure the position of the active device to an accuracy of better than 1.0 meter to determine the position of a reference point, wherein the active device is a mobile device and the reference point is a mobile reference point;
the RFID reading system having a RF receiver configured to:
(i) detect a first RF signal from the reference RFID tag, wherein: (a) the reference RFID tag is more than 3.0 meter away from said RF receiver, (b) the radio locating system is a type of system that is different from the RFID reading system, (c) the reference RFID tag is located essentially at the same position of the mobile reference point, and (d) the distance between the reference RFID tag and the reference point is less than 0.2 meter; and
(ii) detect a second RF signal from the RFID tag of interest; and

a controller configured to process both the first RF signal and the second RF signal and to rely upon at least partially the position of the reference point to determine the position of the RFID tag of interest.

21. The apparatus of claim 20 , wherein the radio locating system comprises:
a plurality of radio locating devices distributed at multiple locations.

22. The apparatus of claim 20 , wherein the controller is configured to process at least one of:
the difference between the time stamp of the first RF signal and the time stamp of the second RF signal;
the difference between the received signal strength indicator (RSSI) of the first RF signal and the RSSI of the second RF signal; and
the difference between the phase of the first RF signal and the phase of the second RF signal.

23. The apparatus of claim 20 , wherein the controller is configured to process both the first RF signal and the second RF signal to determine an offset between the position of the RFID tag of interest and the position of the reference point.

Assignees

• Symbol Technologies Inc
• Symbol Technologies Llc

Inventors

• Connolly Sean A
• Wulff Thomas E

Classifications

• G01S13/751 Primary

  wherein the responder or reflector radiates a coded signal · CPC title

• G01S5/0284 Primary

  Relative positioning · CPC title

• G06K9/00362

  Physics · mapped topic

• G06K7/10009

  sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves · CPC title

• G01S3/14

  Systems for determining direction or deviation from predetermined direction {(aerial arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00; combinations of different interacting aerial units for giving a desired directional characteristic H01Q21/29; aerials or aerial systems providing at least two radiation patterns H01Q25/00)} · CPC title