Network for locating a wireless tag

• US 20070096984A1
• Filed: 09/23/2004
• Published: 05/03/2007
• Est. Priority Date: 09/27/2003
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Bird, Neil, Leitch, Adam
• Granted Patent: US 7,679,523 B2
• Time in Patent Office: Days
• US Class Current: 342/453
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 1/68 Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks

Abstract

A network for locating a wireless tag comprises a plurality of wireless nodes. The nodes are not connected together by a wired network. Each node is included in a floor tile for installation inside a building and configured to be wirelessly connectable to at least one other node. When the floor tiles are installed, the plurality of nodes form a mesh or grid and provide overlapping wireless coverage for locating the tag by reference to mesh.

Claims

11. A network for locating a wireless tag said network comprising:

a layer for installation inside a building; and

a plurality of independent wireless nodes included in said layer, each node configured to be wirelessly connectable to at least one other node.

1. A network for locating a wireless tag said network comprising a plurality of independent wireless nodes, each node being included in a layer or respective layer unit for installation inside a building and configured to be wirelessly connectable to at least one other node such that when said layer or layer units are installed, said plurality of nodes have a determinable spaced arrangement and provide overlapping wireless coverage for locating said tag by reference to said spaced arrangement.

2. A network according to claim 1, wherein said layer comprises a floor covering.

3. A network according to claim 1, wherein said layer comprises a carpet underlay.

4. A network according to claim 1, wherein layer units include tiles for covering a floor.

5. A network according to claim 1, wherein said layer units include tiles for covering a ceiling.

6. A network according to claim 1, wherein said spaced arrangement comprises a regular pattern of nodes.

7. A network according to claim 1, wherein each wireless node includes means for receiving a wireless signal and means for transmitting a wireless signal.

8. A network according to claim 1, wherein each wireless node includes means for determining a range to a neighbouring wireless mode.

9. A network according to claim 8, wherein said means for determining a range comprises means for determining a time of arrival of a received signal.

10. A network according to claim 8, wherein said means for determining a range comprises means for determining a value of signal strength of a received signal.

13. A network according to claim 11 further comprising means for generating power for a wireless node.

14. A network or a network element according to claim 13, wherein said means for generating power comprises a piezoelectric crystal.

15. A network according to claim 11 or a network element according to claim 12, further comprising means for receiving power for a wireless node from an external source.

16. A network or a network element according to claim 15, wherein said means for receiving power comprises inductive means.

12. A network element for forming part of a network for locating a wireless tag, said network element comprising:

a layer unit for installation inside a building; and

an independent wireless node included in said layer unit and configured to be wirelessly connectable to at least one other node.

16-1. A network or a network element according to claim 15, wherein said means for receiving power comprises inductive means.

17. A method of locating a wireless tag using a network comprising a plurality of independent wireless nodes each node being included in a layer or respective layer unit installed inside a building and configured to be wirelessly connectable to at least one other node, the method comprising:

determining a spaced arrangement of said wireless nodes; and

determining the location of said wireless tag with reference to said spaced arrangement.

18. A method according to claim 17, wherein determining said spaced arrangement of said wireless nodes comprises:

transmitting a first message from a first node said first message identifying said first node;

noting a time of arrival of said first message at a second node and

transmitting a second message from said second node, said second message identifying said first and second nodes, the time of arrival of said first message and a time of transmission of said second message.

19. A method according to claim 18, further comprising:

transmitting a message from said first node identifying the location of said first node within said spaced arrangement.

20. A method of operating a wireless node included in a layer or respective layer unit installed inside a building and configured to be wirelessly connectable to at least one other node, the method comprising:

co-operating with said at least one other node so as to determine location of said wireless node within a spaced arrangement of wireless nodes and

co-operating with a wireless tag so as to determine location of said wireless tag with reference to said spaced arrangement of wireless nodes.

21. A computer program comprising instructions which, when executed by data processing apparatus causes said data processing apparatus to perform the method according to claim 20.