Method and apparatus for calculating a device location

• US 7,616,965 B2
• Filed: 07/31/2006
• Issued: 11/10/2009
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Strutt, Guenael T., Goldberg, Keith J., Rudravaram, Pavan K.
• Primary Examiner(s): Appiah, Charles N
• Assistant Examiner(s): DOAN, KIET M
• Application Number:
  US11/461,178
• Publication Number:
  US 20080026770A1
• Time in Patent Office: 1,198 Days
• Field of Search: 455/446, 455/456.1, 455/456.2, 455/456.3, 375/141
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 4/021 Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 4/33 for indoor environments, e.g. buildings
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and apparatus for calculating a location of a device is provided. A likelihood of the device being located at a particular location point or a particular location floor is determined using a likelihood calculation at each of a plurality of locations. The location point or location floor is then identified as that location having an associated highest likelihood calculation. The likelihood calculation includes calculating a distance from the device to each of a plurality of reference routers including one or more virtual coplanar reference routers, wherein each of the one or more virtual coplanar reference routers comprise a projection of a non-coplanar reference router onto the floor.

Claims

1. A method for determining a location floor of a device within a building, the method comprising:

determining a likelihood of the device being located on each of a plurality of floors of the building using a likelihood calculation; and

identifying the location floor of the plurality of floors as a floor having an associated highest likelihood calculation,

wherein the likelihood calculation for a floor includes calculating a distance from the device to each of a plurality of reference routers including one or more virtual coplanar reference routers, wherein each of the one or more virtual coplanar reference routers comprise a projection of a location of a non-coplanar reference router located on another floor to a virtual reference point within the floor, and wherein calculating the distance to each of the one or more virtual coplanar reference routers comprises calculating a virtual time of arrival between the device and the virtual coplanar reference router by;

calculating a time of arrival between the device and the non-coplanar reference router

determining a distance between the other floor and the floor, and using the time of arrival and the distance, and

calculating the virtual time of arrival using the time of arrival and the distance, wherein the projection of the non-coplanar reference router comprises projecting a three dimensional measurement onto a two dimensional plane.

2. A method for determining a location of a device within a building as claimed in claim 1, wherein the projection of the location of the non-coplanar reference router includes calculating the distance between a reference router floor in which the non-coplanar reference router is located and the floor.

3. A method for determining a location of a device within a building as claimed in claim 1, wherein calculating the distance to each of the plurality of reference routers comprises calculating a time of arrival between the device and the reference router.

4. A method for determining a location of a device within a building as claimed in claim 1, wherein the virtual time of arrival is calculated by:

TOA′

=√

{square root over (TOA²−

H²)}

where TOA′

is the virtual time of arrival

TOA is the time of arrival, and

H is the distance between the first floor and the second floor.

5. A method for determining a location point of a device within a floor of a building, the method comprising:

determining a likelihood of the device being located at each of a plurality of locations on the floor using a likelihood calculation; and

identifying the location point of the plurality of locations as the location having an associated highest likelihood calculation,

wherein the likelihood calculation for a location includes calculating a distance from the device to each of a plurality of reference routers including one or more virtual coplanar reference routers, wherein each of the one or more virtual coplanar reference routers comprise a projection of a location of a non-coplanar reference router located on an other floor to a virtual reference point within the floor, wherein calculating the distance to each of the one or more virtual coplanar reference routers comprises calculating a virtual time of arrival between the device and the virtual coplanar reference router, and further wherein calculating the virtual time of arrival comprises;

calculating a time of arrival between the device and the non-coplanar reference router,

determining a distance between the other floor and the floor, and using the time of arrival and the distance, and

calculating the virtual time of arrival using the time of arrival and the distance, wherein the projection of the location of the non-coplanar reference router comprises projecting a three dimensional measurement onto a two dimensional plane.

6. A method for determining a location of a device within a floor of a building as claimed in claim 5, further comprising prior to the determining step:

identifying the floor.

7. A method for determining a location of a device within a floor of a building as claimed in claim 6, wherein the identifying the floor step comprises:

determining a likelihood of the device being located on each of a plurality of floors of the building using a likelihood calculation; and

identifying a location floor of the plurality of floors as a floor having an associated highest floor likelihood calculation,

wherein the floor likelihood calculation for a floor includes calculating a distance from the device to each of a plurality of reference routers including one or more virtual coplanar reference routers, wherein each of the one or more virtual coplanar reference routers comprise a projection of a location of a non-coplanar reference router to a virtual reference point within the floor.

8. A method for determining a location point of a device within a floor of a building as claimed in claim 5, wherein the projection of the non-coplanar reference router includes calculating the distance between a reference router floor in which the non-coplanar reference router is located and the floor.

9. A method for determining a location point of a device within a floor of a building as claimed in claim 5, wherein calculating the distance to each of the plurality of reference routers comprises calculating a time of arrival between the device and the reference router.

10. A method for determining a location point of a device within a floor of a building as claimed in claim 5, wherein the virtual time of arrival is calculated by:

TOA′

=√

{square root over (TOA²−

H²)}

where TOA′

is the virtual time of arrival

TOA is the time of arrival, and

H is the distance between the first floor and the second floor.

11. A system for determining a location of a mobile device within a building, the system comprising:

a plurality of reference routers communicating within a wireless network and communicatively coupled to the mobile device; and

an incident command console communicatively coupled to the wireless network, the incident command console including;

a memory for storing position information associated with each of the plurality of reference routers, and

a processor for calculating the location of the mobile device by;

determining a likelihood of the device being located on each of a plurality of floors of the building using a likelihood calculation; and

identifying the location floor of the plurality of floors as a floor having an associated highest likelihood calculation,

wherein the likelihood calculation for a floor includes calculating a distance from the device to each of a plurality of reference routers including one or more virtual coplanar reference routers, wherein each of the one or more virtual coplanar reference routers comprise a projection of a location of a non-coplanar reference router located on an other floor to a virtual reference point within the floor, wherein calculating the distance to each of the one or more virtual coplanar reference routers comprises calculating a virtual time of arrival between the device and the virtual coplanar reference router, and further wherein calculating the virtual time of arrival comprises;

calculating a time of arrival between the device and the non-coplanar reference router,

determining a distance between the other floor and the floor, and using the time of arrival and the distance, and

calculating the virtual time of arrival using the time of arrival and the distance,

wherein the projection of the location of the non-coplanar reference router comprises projecting a three dimensional measurement onto a two dimensional plane.

12. A system for determining a location of a mobile device within a building as claimed in claim 11 wherein the wireless network comprises an ad-hoc wireless multi-hopping communications network.