LOCATION ESTIMATION BY OBSERVING WIRELESS SIGNALS

• US 20110182238A1
• Filed: 02/03/2011
• Published: 07/28/2011
• Est. Priority Date: 08/06/2008
• Status: Active Grant

• Current Assignee: U-Blox AG (u-blox Holding AG)
• Original Assignee: U-Blox AG (u-blox Holding AG)
• Inventors: Marshall, Christopher, Yale, Andrew Thomas
• Granted Patent: US 8,804,551 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• 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 estimating the position of an electronic device. The method comprises: receiving an observation comprising the identity of at least one wireless transmitter detected by the device at the position to be estimated; comparing the observation with the contents of a set of records; detecting respective first and second matches between the observation and records, and retrieving the corresponding positions. The method comprises estimating the position of the electronic device based on at least one of the first position estimate and the second position estimate, depending upon quality characteristics of the first match and the second match and indications of the sources of the respective records.

Claims

1. A method of estimating the position of an electronic device, comprising:

receiving an observation including the identity of at least one wireless transmitter detected by the device at the position to be estimated;

comparing the observation with a plurality of records, each record comprising the identity of one or more wireless transmitters and a corresponding position, the position being based on a location or set of locations at which the one or more transmitters were detected;

detecting a first match between the observation and a first record, the first record comprising a corresponding first position;

determining a first indication of the source of the first record;

detecting a second match between the observation and a second record, the second record comprising a corresponding second position;

determining a second indication of the source of the second record, wherein the second indication is different from the first indication; and

estimating the position of the electronic device based on at least one of the first and second positions, depending upon the first indication and the second indication.

2. The method of claim 1, wherein at least one of the first and second indications of source indicates at least one of:

the identity of one or more devices which contributed to the record by having detected the one or more transmitters at the location or set of locations;

the identity of one or more software programs which caused said one or more devices to contribute the record and

a group to which said one or more devices or software programs belong,

wherein said group is preferably associated with at least one of;

a type of said one or more devices or software programs; and

a user or group of users with which said one or more devices or software programs are associated.

3. The method of claim 2, wherein:

the first indication indicates that the source of the first record is the electronic device itself; and

preferably

the second indication indicates that the source of the second record is one or more devices among a limited group of devices.

4. The method of claim 1, wherein at least one of the firs and second indications comprises a label in the respective matched record.

5. The method of claim 1, wherein if the first and second indications suggest that the first record originates from a source that is more closely related to the electronic device than the source of the second record, then the estimation is based preferentially on the first position.

6. The method of claim 1, wherein the step of estimating the position of the electronic device comprises a linear or non-linear combination of the first and second positions.

7. The method of claim 6, wherein:

the position corresponding to each match is assigned a priority, wherein each priority is based on the indication of the source of the corresponding record; and

the step of estimating the position of the electronic device comprises selecting the position having the highest priority.

8. The method of claim 6, wherein:

the position corresponding to each match is assigned a weight, wherein each weight is based on the indication of the source of the corresponding record; and

the step of estimating the position of the electronic device comprises calculating a weighted average of the positions according to the assigned weights.

9. The method of claim 1, further comprising determining a quality characteristic of the first match and a quality characteristic of the second match,

wherein the step of estimating the position of the electronic device depends upon the first indication, the quality characteristic of the first match, the second indication and the quality characteristic of the second match.

10. The method of claim 9, wherein the quality characteristic of the first match and second match comprises a measure of how specific each match is, preferably comprising at least one of:

a degree of similarity between the set of at least one identity comprised in the observation and the set of one or more identities comprised in the matched record; and

a degree of geographic precision implied by the match.

11. The method of claim 10, wherein the identity of each transmitter has a hierarchical structure, whereby successive levels of the hierarchy correspond to successively more limited geographic areas;

and

wherein the measure of specificity of the match is based on the degree of similarity between the hierarchical identity of the at least one transmitter in the observation and hierarchical identity of the one or more transmitters in the matched record.

12. The method of claim 10, wherein the first and second indications suggest that the first record originates from a source that is more closely related to the electronic device than the source of the second record, wherein:

if the second match is more specific than the first match, then the estimation of the position of the electronic device is based preferentially on the second position;

otherwise the estimation is based preferentially on the first position.

13. The method of claim 9, wherein:

the position corresponding to each match is assigned a priority,

wherein each priority is based jointly on;

the quality characteristic of the match; and

the indication of the source of the corresponding record, and

the step of estimating the position of the electronic device comprises selecting the position having the highest priority.

14. The method of claim 9, wherein:

the position corresponding to each match is assigned a weight, wherein each weight is based jointly on;

the quality characteristic of the match; and

the indication of the source of the corresponding record, and

the step of estimating the position of the electronic device comprises calculating a weighted average of the positions according to the assigned weights.

15. The method of claim 1, further comprising submitting data to the plurality of records, the data comprising:

the observation;

an estimate of the position of the electronic device; and

preferably

a label identifying at least one of;

the electronic device;

its type;

or a group of devices to which it belongs.

16. A computer program comprising computer program code means adapted to perform all the steps of claim 1 if said program is run on a computer.

17. A computer program as claimed in claim 16 embodied on a computer readable medium.

18. A portable device, comprising:

a wireless receiver, adapted to observe the identity of at least one wireless transmitter detectable by the device at a position to be estimated;

a query processor, operable to issue the observed identity as a query to be compared with a plurality of records, each record comprising the identity of one or more wireless transmitters and a corresponding position, the position being based on a location or set of locations at which the one or more transmitters were detected,

the query processor being operable to receive, in response to the query, the result of a first match between the observation and a first one of the records, the result comprising;

a first indication of the source of the first record;

a first position estimate, being the position corresponding to the first record,

the query processor also being operable to receive, in response to the query, the result of a second match between the observation and a second one of the records, the result comprising;

a second indication of the source of the second record, wherein the second indication is different from the first indication;

a second position estimate, being the position corresponding to the second record; and

a position estimator, adapted to estimate the position of the portable device based on at least one of the first position estimate and the second position estimate, depending upon the first indication and the second indication.

19. The portable device of claim 18, further comprising an onboard memory, for storing the whole or part of the plurality of records.