RF tracking system and method

• US 20040027251A1
• Filed: 08/08/2002
• Published: 02/12/2004
• Est. Priority Date: 08/08/2002
• Status: Active Grant

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Sharony, Jacob
• Granted Patent: US 7,019,663 B2
• Time in Patent Office: Days
• US Class Current: 340/825.49
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations

Abstract

Described is a system and method for tracking an asset. The system may include an RF tag coupled to the asset; a wireless wide area network (“WWAN”) including a plurality of transceivers and having a first coverage area; and a plurality of wireless local area networks (“WLAN”). Each of the WLANs has a second coverage area within the first coverage area. In addition, the system includes a computer which communicates with the WWAN and the WLANs. The computer generates a signal to be transmitted to the asset using a first transceiver of the WWAN. The asset receives the signal and generates a response signal; the asset transmits the response signal to a particular WLAN within which second coverage area the asset is located via a plurality of second transceivers. The computer determines the location of the asset within the second coverage area as a function of the response signal.

Claims

1. A system for tracking a location of an asset, comprising:

an RF tag coupled to the asset;

a wireless wide area network (“

WWAN”

) including a first transceiver and having a first coverage area;

a plurality of wireless local area networks (“

WLAN”

), each of the WLANs having a second coverage area within the first coverage area and a plurality of second transceivers; and

a computer communicating with the WWAN and the WLANs, the computer generating a signal and transmitting the signal to the asset over the first coverage area using the first transceiver,

wherein the RF tag receives the signal and generates a response signal to the signal, the response signal being transmitted to one WLAN of the plurality of WLANs, the RF tag being located within the second coverage area of the one WLAN, and

wherein the second transceivers receive the response signal and forward it to the computer, the computer determining the location of the asset within the particular WLAN as a function of the response signal.

2. The system according to claim 1, wherein the computer determines the location of the asset as a function of at least one of the signal, a first reception time of the signal by the RF tag, a second reception time of the response signal by the second transceivers, a first power strength of the signal, a second power strength of the response signal and a location of each of the second transceivers.

3. The system according to claim 1, wherein the plurality of second transceivers includes at least three transceivers.

4. The system according to claim 1, wherein the RF tag is a dual-mode tag capable of communications with the WWAN and the WLANs.

5. The system according to claim 1, wherein the WLAN is an IEEE 802.11 network.

6. The system according to claim 1, wherein the signal is a high power low bit-rate signal.

7. The system according to claim 1, wherein the response signal is a low power high bit-rate signal.

8. A computing arrangement for tracking a location of an asset having a RF tag, comprising:

a processor;

a memory device coupled to the processor; and

a communication device,

wherein the processor generates a signal and transmits the signal, via the communication device, to the asset using a first transceiver of a wireless wide area network (“

WWAN”

), the WWAN having a first coverage area,

wherein the RF tag receives the signal and generates a response signal to the signal, the response signal being transmitted to a wireless local area network (“

WLAN”

), the WLAN having a second coverage area which is within the first coverage area, and

wherein the WLAN receives the response signal via a plurality of second transceivers and forwards it to the processor, the processor determining the location of the asset within the second coverage area as a function of the response signal.

9. The computer arrangement to claim 8, wherein the processor determines the location of the asset as a function of at least one of the signal, a first reception time of the signal by the RF tag, a second reception time of the response by the second transceivers, a first power strength of the signal, a second power strength of the response signal and a location of each of the second transceivers.

10. The computing arrangement according to claim 8, wherein the signal is a high power low bit-rate signal.

11. The computing arrangement according to claim 8, wherein the response signal is a low power high bit-rate signal.

12. A method for tracking a location of an asset having an RF tag, the asset being located within a wireless wide area network (“

WWAN”

), the WWAN including a plurality of wireless local area networks (“

WLANs”

), the method comprising the steps of;

generating a signal;

transmitting the signal to the asset using a first transceiver of the WWAN;

receiving a response signal from the asset via a plurality of second transceivers of a particular one of the WLANs; and

determining the location of the asset within the particular WLAN as a function of the response signal.

13. The method according to claim 12, wherein in the determining step, the location of the asset is determined as a function of at least one of the signal, a first reception time of the signal by the RF tag, a second reception time of the response by the second transceivers, a first power strength of the signal, a second power strength of the response signal and a location of each of the second transceivers.

14. The method according to claim 12, wherein the signal is a high power low bit-rate signal.

15. The method according to claim 12, wherein the response signal is a low power high bit-rate signal.

16. A system for tracking a location of an asset, comprising:

an RF tag coupled to the asset;

a wireless wide area network (“

WWAN”

) including a first transceiver and having a first coverage area;

a plurality of wireless local area networks (“

WLAN”

), each of the WLANs having a second coverage area within the first coverage area and including a plurality of second transceivers; and

a computer communicating with the WWAN and the WLANs, the computer generating a first signal and transmitting the first signal to the asset using the first transceiver,

wherein the RF tag receives the first signal and generates a first response in response to the first signal, the first response being transmitted to the WWAN,

wherein the computer determines a particular WLAN within which coverage area the asset is located as a function of the first signal and the first response, the computer generating a second signal and transmitting the second signal to the asset using the second transceivers of the particular WLAN,

wherein the RF tag receives the second signal and transmits a second response to the second signal to the particular WLAN, and

wherein the computer determines the location of the asset within the particular WLAN as a function of the second signal.

17. The system according to claim 16, wherein the computer determines the location of the asset as a function of at least one of the signal, a first reception time of the signal by the RF tag, a second reception time of the response by the second transceivers, a first power strength of the signal, a second power strength of the response signal and a location of each of the second transceivers.

18. The system according to claim 16, wherein the plurality of second transceivers includes at least three transceivers.

19. The system according to claim 16, wherein the RF tag is a dual mode tag capable of communications with the WWAN and the WLANs.

20. The system according to claim 16, wherein the WLAN is IEEE 802.11 network.

21. The system according to claim 16, wherein the first signal is a high power low bit-rate signal.

22. The system according to claim 16, wherein each of the second signal and the second response is a low power high bit-rate signal.

23. A computing arrangement for tracking a location of an asset having a RF tag, comprising:

a processor;

a memory device coupled to the processor; and

a communication device,

wherein the processor generates a first signal and transmits the first signal, via the communication device, to the asset using a first transceiver of a wireless wide area network (“

WWAN”

), the WWAN having a first coverage area,

wherein the RF tag receives the first signal and generates a first response in response to the first signal, the first response being transmitted to the WWAN,

wherein the processor determines a particular wireless local area network (“

WLAN”

) of a plurality of WLANs within which coverage area the asset is located as a function of the first signal and the first response, each of the WLANs having a second coverage area within the first coverage area and a plurality of second transceivers,

wherein the processor generates a second signal and transmits, via the communication device, the second signal to the RF tag using the second transceivers;

wherein the RF tag receives the second signal and transmit a second response in response to the second signal to the particular WLAN, and

wherein the processor determines the location of the asset within the second coverage area as a function of the second response.

24. The computing arrangement according to claim 23, wherein the computer determines the location of the asset as a function of at least one of the signal, a first reception time of the signal by the RF tag, a second reception time of the response by the second transceivers, a first power strength of the signal, a second power strength of the response signal and a location of each of the second transceivers.

25. The computing arrangement according to claim 23, wherein the first signal is a high power low bit-rate signal.

26. The computing arrangement according to claim 23, wherein each of the second signal and the second response is a low power high bit-rate signal.

27. A method for tracking a location of an asset having an RF tag, the asset being located within a wireless wide area network (“

WWAN”

), the WWAN including a plurality of wireless local area networks (“

WLANs”

), the method comprising the steps of;

generating a first signal;

transmitting the first signal to the asset using a first transceiver of the WWAN;

receiving a first response from the asset, the first response being generated in response to the first signal;

determining a particular WLAN where the asset is located as a function of the first signal and the first response;

generating a second signal;

transmitting the second signal to the asset using a second transceiver of the particular WLANs;

receiving a second response from the asset to the second signal; and

determining the location of the asset within the particular WLAN as a function of the second response.