SYSTEM FOR DETERMINING ITEM LOCATION BASED ON FEEDBACK FROM FIXED RADIO FREQUENCY IDENTIFICATION (RFID) READERS AND/OR FIXED RFID BEACON TAGS

• US 20100201520A1
• Filed: 02/12/2009
• Published: 08/12/2010
• Est. Priority Date: 02/12/2009
• Status: Abandoned Application

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Bekrisky, Benjamin, Stern, Miklos
• Application Number:
  US12/369,866
• Publication Number:
  US 20100201520A1
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/75 using transponders powered from received waves, e.g. using passive transponders , or using passive reflectors
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence

Abstract

The present disclosure describes a system, methods and apparatus for determining location of an item within a space. Each particular item is associated with a particular Radio Frequency Identification (RFID) item tag that uniquely identifies the particular item. A plurality of fixed Radio Frequency Identification (RFID) readers are provided in the space, and each of the fixed RFID readers is fixed at a particular known location within the space. Each of the fixed RFID readers can transmit an interrogation signal. Upon receiving a first interrogation signal from one of the fixed RFID readers, a first RFID item tag transmits a response signal. The first fixed RFID reader receives the response signal transmitted by the first RFID item tag, and can therefore determine that the first RFID item tag is located within a read range of the first fixed RFID reader.

Claims

1. A method for determining item location within a space based on feedback from a fixed Radio Frequency Identification (RFID) reader and fixed RFID beacon tags, the method comprising:

transmitting a first interrogation signal from a first fixed RFID reader at a first transmit power, wherein the first fixed RFID reader is fixed at a first known location within the space;

transmitting a response signal from each of a first set of fixed RFID beacon tags and from each of a first set of RFID item tags upon receiving the first interrogation signal, wherein each of the fixed RFID beacon tags are fixed at known locations and, wherein the first set of RFID item tags comprises a first RFID item tag;

defining a first coverage area of the first fixed RFID reader based on one or more of;

the first known location of the first fixed RFID reader and the known locations of the first set of fixed RFID beacon tags; and

determining that the first set of RFID item tags are located within the first coverage area of the first fixed RFID reader.

2. A method according to claim 1, further comprising:

transmitting a second interrogation signal from a second fixed RFID reader that is fixed at a second known location within the space;

transmitting response signals from a second set of fixed RFID beacon tags and from a second set of RFID item tags upon receiving the second interrogation signal, wherein each of the second set of fixed RFID beacon tags are fixed at other known locations;

defining a second coverage area of the second fixed RFID reader based on one or more of;

the second known location of the second fixed RFID reader and the other known locations of the second set of fixed RFID beacon tags; and

determining that the second set of RFID item tags are located within the second coverage area of the second fixed RFID reader.

3. A method according to claim 2, wherein each of the first and second fixed RFID readers, comprise a battery that powers the first and second fixed RFID readers.

4. A method according to claim 3, wherein each of the batteries is rechargeable via ambient lighting.

5. A method according to claim 1, wherein each of the RFID item tags is attached to an item.

6. A Radio Frequency Identification (RFID) system for determining item location within a space, the RFID system comprising:

a first fixed RFID reader designed to transmit a first interrogation signal at a first transmit power, wherein the first fixed RFID reader is fixed at a first known location within the space;

a first set of fixed RFID beacon tags designed to transmit response signals upon receiving the first interrogation signal, wherein each of the fixed RFID beacon tags are fixed at other known locations;

a first set of RFID item tags designed to transmit response signals upon receiving the first interrogation signal, wherein the first set of RFID item tags comprises a first RFID item tag;

wherein the first fixed RFID reader is designed to define a first coverage area of the first fixed RFID reader based on the first known location and the known locations of the first set of fixed RFID beacon tags, and to determine that the first set of RFID item tags are located within the first coverage area of the first fixed RFID reader.

7. A RFID system according to claim 6, further comprising:

a second fixed RFID reader designed to transmit a second interrogation signal, wherein the second fixed RFID reader is fixed at a second known location within the space;

a second set of fixed RFID beacon tags designed to transmit response signals in response to receiving the second interrogation signal, wherein each of the second set of fixed RFID beacon tags are fixed at other known locations; and

a second set of RFID item tags designed to transmit response signals in response to receiving the second interrogation signal, wherein the second set of RFID item tags comprise at least one RFID item tag;

wherein the second fixed RFID reader is designed to define a second coverage area of the second fixed RFID reader based on the second known location of the second fixed RFID reader and the other known locations of the second set of fixed RFID beacon tags, and to determine that the second set of RFID item tags are located within the second coverage area of the second fixed RFID reader.

8. A RFID system according to claim 7, wherein each of the first and second fixed RFID readers comprise a battery that powers the first and second fixed RFID readers.

9. A RFID system according to claim 8, wherein each of the batteries is rechargeable via ambient lighting.

10. A RFID system according to claim 7, wherein each of the RFID item tags is attached to an item.

11. A Radio Frequency Identification (RFID) system for determining item location within a space, the RFID system comprising:

a first fixed RFID reader designed to transmit a first interrogation signal at a first transmit power, wherein the first fixed RFID reader is fixed at a first known location within the space;

a first set of fixed RFID beacon tags designed to transmit response signals upon receiving the first interrogation signal, wherein the fixed RFID beacon tags are fixed at other known locations;

a first set of RFID item tags designed to transmit response signals upon receiving the first interrogation signal, wherein each of the RFID item tags is attached to an item, and wherein the first set of RFID item tags comprises a first RFID item tag; and

a monitoring server designed to receive the identification information from the first fixed RFID reader that identifies first set of fixed RFID beacon tags and the first set of RFID item tags, and to define a first coverage area of the first fixed RFID reader based on the first known location and other known locations the first set of fixed RFID beacon tags, and to determine that the first set of RFID item tags are located within the first coverage area of the first fixed RFID reader.

12. A method for determining location of an item within a space, the method comprising:

providing a plurality of fixed Radio Frequency Identification (RFID) readers in the space, wherein each of the fixed RFID reader is fixed at a particular known location within the space;

transmitting interrogation signals from each of the fixed RFID readers;

transmitting a response signal from a first RFID item tag upon receiving a first interrogation signal from a first fixed RFID reader of the plurality of fixed RFID readers; and

receiving the response signal at the first fixed RFID reader, and

determining that the first RFID item tag is located in the space within a first coverage area of the first fixed RFID reader.

13. A method for verifying Radio Frequency Identification (RFID) reader coverage of a space, comprising:

placing a plurality of fixed RFID readers and a plurality of fixed RFID beacon tags at known locations within the space;

transmitting interrogation signals from the fixed RFID readers;

transmitting response signals from at least some of the fixed RFID beacon tags upon receiving one of the interrogation signals;

receiving response signals from at least some of the fixed RFID beacon tags at least some of the fixed RFID readers;

extracting identification information from the response signals received from the at least some of the fixed RFID beacon tags at some of the fixed RFID readers, and communicating the identification information to a monitoring server; and

verifying, at the monitoring server, that the fixed RFID readers provide full coverage of the space by determining whether identification information for all of the fixed RFID beacon tags was received by at least one of the fixed RFID readers.

14. A method according to claim 13, wherein the monitoring server determines that the fixed RFID readers provide full coverage of the space when all of the fixed RFID beacon tags transmitted a response signal that was received by at least one of the fixed RFID readers.

15. A method according to claim 13, wherein the monitoring server determines that the fixed RFID readers do not provide full coverage of the space when one or more of the fixed RFID beacon tags did not transmit a response signal that was received by at least one of the fixed RFID readers.

16. A method according to claim 13, further comprising:

determining, at a first fixed RFID reader of the plurality of fixed RFID readers, an approximate location where the first fixed RFID reader is located based on particular locations of particular ones of the fixed RFID beacon tags that the first fixed RFID reader received response signals from.

17. A method for determining coverage area of a Radio Frequency Identification (RFID) reader based on feedback from fixed RFID beacon tags, the method comprising:

transmitting a first interrogation signal from the RFID reader;

transmitting a response signal from each of a first set of fixed RFID beacon tags upon receiving the first interrogation signal, wherein each of the fixed RFID beacon tags are fixed at known locations;

measuring a signal strength value associated with each of the response signals; and

defining a coverage area of the RFID reader based on one or more of;

a first known location of the RFID reader, known locations of the first set of fixed RFID beacon tags, and measured signal strength values associated with each of the response signals.

18. A method for determining relative location of a particular item within a retail store that comprises a plurality of Radio Frequency Identification (RFID) readers, the method comprising:

transmitting, in response to a command to look for the particular item, interrogation signals from each of the RFID readers to interrogate RFID item tags within a read range of each of the RFID readers;

transmitting a particular response signal from a first RFID item tag upon receiving a first interrogation signal from a first RFID reader of the plurality of RFID readers;

receiving response signals at each of the RFID readers, the response signals including the particular response signal;

communicating the response signals to a monitoring server; and

determining, at the monitoring server, that the first RFID item tag is located within a first coverage area of the first RFID reader.

19. A method for determining relative location of a particular item within a retail store that comprises a plurality of Radio Frequency Identification (RFID) readers, the method comprising:

transmitting, in response to a command to look for the particular item, interrogation signals from each of the RFID readers to interrogate RFID item tags within a read range of each of the RFID readers;

transmitting a particular response signal from a first RFID item tag upon receiving a first interrogation signal from a first RFID reader of the plurality of RFID readers;

receiving the particular response signal at the first RFID reader and determining that the particular item is located within read range of the first RFID reader;

communicating a signal from the first RFID reader to a monitoring server over a wireless communication link, wherein the signal indicates that the first RFID item tag is located within a first coverage area of the first RFID reader; and

determining at the monitoring server based on the signal that the first RFID item tag is located within the first coverage area of the first RFID reader.

20. A method for determining location of a Radio Frequency Identification (RFID) reader located within a space based on feedback from fixed RFID beacon tags, the method comprising:

transmitting an interrogation signal from the RFID reader;

transmitting a response signal from each of a first set of fixed RFID beacon tags upon receiving the interrogation signal, wherein each of the fixed RFID beacon tags are fixed at known locations; and

determining a location of the RFID reader and a coverage area of the RFID reader based on the known locations of the first set of fixed RFID beacon tags.