Determining physical location based upon received signals

• US 7,933,612 B2
• Filed: 06/30/2006
• Issued: 04/26/2011
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Glenner, Steve C., Krumm, John C., Schwartz, Jordan L. K., Counts, Scott J.
• Primary Examiner(s): Pan; Yuwen
• Application Number:
  US11/427,957
• Publication Number:
  US 20070202887A1
• Time in Patent Office: 1,761 Days
• Field of Search: 455/456.1, 455/456.2, 455/456.5, 455/457
• US Class Current: 455/457
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/0295 Proximity-based methods, e.g. position inferred from reception of particular signals
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

The subject disclosure pertains to systems and methods for determining locations of mobile devices. In particular, a set of regions is defined based upon the relative strength of signals received from one or more base stations within the region. Each region has associated location information (e.g., latitude and longitude). The location of a mobile device can be determined by analyzing the strength of received signals, identifying base stations and generating an ordered list of base stations based upon signal strength. The ordered list can be compared to the set of regions to determine the region in which the mobile device is located. The location information for the retrieved region can be used to estimate the location of the mobile device.

Claims

1. A system for determining a location of a mobile device, comprising:

a receiver component for the mobile device that receives signals from a plurality of base stations;

a ranking component that generates a ranking of base stations based upon signal strengths of signals received at a specific mobile device location;

a rank region data store that maintains a plurality of rank regions, each of the plurality of rank regions being associated with a physical region and being defined by a base station ranking of signal strengths of a plurality of base stations, the signal strengths measured at one or more particular locations located within the physical region and each of the plurality of rank regions having location information including a location estimate for the rank region, the location estimate being based at least in part on the one or more particular locations; and

a search component that obtains location information from the rank region data store by matching the generated ranking of base stations to one of the base station rankings defining one of the rank regions and retrieving the location information associated with that rank region.

2. The system of claim 1, wherein the location information includes a confidence indicator that indicates the accuracy of the location information.

3. The system of claim 1, further comprising:

an output component that returns the obtained location information.

4. The system of claim 3, wherein the location information associated with the rank region is represented as a single geographic point.

5. The system of claim 3, wherein the location information associated with the rank region is based at least in part upon an average of a plurality of data points within the rank region.

6. The system of claim 1, further comprising:

a confidence component that generates a confidence indicator for the location information.

7. The system of claim 6, wherein the confidence indicator is based at least in part upon the ranking.

8. A method for determining a location of a mobile device, comprising:

obtaining, by a computing device, signals from a plurality of base stations at a specific mobile device location;

generating, by the computing device, an ordered list of the base stations based upon signal strengths of the obtained signals;

matching, by the computing device, the ordered list of base stations to a base station ranking which defines a rank region, the rank region being one of a plurality of rank regions, each of the plurality of rank regions being associated with a physical region and being defined by a base station ranking of signal strengths of a plurality of base stations, the signal strengths measured at one or more particular locations located within the physical region and each of the plurality of rank regions having a location estimate for the rank region, the location estimate being based at least in part on the one or more particular locations; and

obtaining, by the computing device, the location estimate associated with the rank region defined by the matching base station ranking.

9. The method of claim 8, wherein the location estimate is a single geographic point.

10. The method of claim 8, further comprising:

generating the plurality of rank regions based at least in part upon a plurality of input data points for a geographic area.

11. The method of claim 10, wherein generating the plurality of rank regions further comprises:

grouping the plurality of input data points into rank regions based upon received signal strengths for the input data points; and

generating a summary representation for each rank region in the plurality of rank regions.

12. The method of claim 11, wherein generating the summary representation includes averaging the input data points.

13. The method of claim 8, further comprising generating a confidence level for the location estimate.

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

means for receiving signals from a plurality of base stations;

means for generating an ordered list of the base stations based at least in part upon signal strengths of signals received at a specific mobile device location;

means for matching the ordered list of base stations to a base station ranking which defines a rank region, the rank region being one of a plurality of rank regions, each of the plurality of rank regions being associated with a physical region and being defined by a base station ranking of signal strengths of a plurality of base stations, the signal strengths measured at one or more particular locations located within the physical region and each of the plurality of rank regions having location information including a location estimate for the rank region, the location estimate being based at least in part on the one or more particular locations; and

means for obtaining the location information associated with the rank region defined by the matching base station ranking.

15. The system of claim 14, further comprising:

means for obtaining a confidence indicator associated with the rank region defined by the matching base station ranking.

16. The system of claim 15, wherein the confidence indicator is based at least in part upon number of base stations in the generated, ordered list.

17. The system of claim 14, wherein the location information is obtained based upon a subset of the ordered list.