Method and apparatus for determining location

• US 8,224,350 B2
• Filed: 05/22/2009
• Issued: 07/17/2012
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: U-Blox AG (u-blox Holding AG)
• Original Assignee: U-Blox AG (u-blox Holding AG)
• Inventors: Marshall, Chris, Thomason, Graham
• Primary Examiner(s): Doan, Phuoc
• Application Number:
  US12/993,459
• Publication Number:
  US 20110294516A1
• Time in Patent Office: 1,152 Days
• Field of Search: 455/456.1, 455/433, 455/414.3, 455/414.4, 455/414.1, 375/220, 340/539.1, 379/92.02
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting
• CPC Class Codes: G06F 16/29 Geographical information databases
• CPC Class Codes: G06F 16/58 Retrieval characterised by using metadata, e.g. metadata not derived from the content or metadata generated manually
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method of determining the location of a portable device comprises obtaining identities of wireless communication devices detectable by the portable device at a particular location which is to be determined, thereby to obtain a set of identities. The set of identities is compared with the content of a database, which database stores a plurality of findings, to select one or more findings; each finding comprising a reference location and a set of identities of wireless communication devices sighted at that location. The location of the portable device is found based on processing the selected findings.

Claims

1. A method of determining the location of a portable device, comprising:

obtaining identities of wireless communication devices detectable by the portable device at a particular location which is to be determined, thereby to obtain a set of identities;

comparing the set of identities with the content of a database, which database stores a plurality of findings, to select one or more findings;

each finding comprising a reference location and a set of identities of wireless communication devices sighted at that location; and

determining the location of the portable device based on processing the selected findings, comprising selecting a location based on one or more reference locations,

wherein the reference locations to be used are those associated with findings based on;

the number of devices associated to the finding which correspond to identities in the set;

the number of devices associated to the finding which do not correspond to any identities in the set; and

the number of identities in the set which are not identified in the database as being associated to the finding.

2. A method as claimed in claim 1, wherein deriving a location from a plurality of reference locations comprises obtaining an average location from those reference locations.

3. A method as claimed in claim 1, further comprising determining if one or more of the identities of the set should be disregarded.

4. A method as claimed in claim 1, wherein obtaining the identities is carried out by the portable device at the particular position, and determining the location is carried out at a different time and without requiring the portable device location at the time of the location determination to correspond to the particular position.

5. A method as claimed in claim 1, wherein the wireless communication devices comprise short range wireless access points, and the identities comprises MAC addresses.

6. A positioning method comprising:

populating a database with identities of wireless communication devices detectable at a plurality of reference locations; and

determining the location of a portable device using the method of claim 1.

7. A positioning method as claimed in claim 6, wherein the database content is updated using the obtained identities of wireless communication devices detectable by the portable device, once the particular location has been determined.

8. A positioning method as claimed in claim 6, wherein the database is populated by conducting a wardrive and/or by processing wireless communication device information received from other sources.

9. A positioning method, comprising:

determining position based on a satellite positioning system; and

determining location using the method as claimed in claim 1 to assist or enhance the position determination using the satellite positioning system.

10. A method as claimed in claim 1, wherein obtaining identities of detectable wireless communication devices further comprises measuring one or more of:

signal strength,

signal to noise ratio,

error rate,

Doppler frequency.

11. A method as claimed in claim 1, wherein the database content includes, in respect of a signal of a given communication device from a given reference location, one or more of:

signal strength,

signal to noise ratio,

error rate,

Doppler frequency.

12. A method as claimed in claim 1, wherein the step of obtaining identities of wireless communication devices detectable by the portable device at a particular location which is to be determined is carried out using a camera.

13. A method as claimed in claim 12, further comprising appending the identities to an image file to enable subsequent analysis to determine the particular location.

14. A system for determining the location of a portable device, comprising:

the portable device, which comprises a wireless receiver for obtaining identities of wireless communication devices detectable by the portable device at a particular location thereby to obtain a set of identities;

a database which stores the identities of wireless communication devices detectable at a plurality of reference locations;

comparison means, for comparing the set of identities with the content of the database,

location-determination means, for determining the location of the portable device, comprising selecting a location based on one or more reference locations,

wherein the reference locations to be used are those associated with findings based on;

the number of devices associated to the finding which correspond to identities in the set;

the number of devices associated to the finding which do not correspond to any identities in the set; and

the number of identities in the set which are not identified in the database as being associated to the finding.