Methods and Apparatus for Mobile Station Location Estimation

• US 20140213287A1
• Filed: 03/18/2014
• Published: 07/31/2014
• Est. Priority Date: 04/03/2001
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: MacDonald, Alan Denis, Sather, Marc W., Snapp, John Lawrence
• Granted Patent: US 9,439,167 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04W 4/026 using orientation information, e.g. compass
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/003 locating network equipment
• CPC Class Codes: H04W 88/14 Backbone network devices

Abstract

Methods and apparatus for estimating mobile station location include receiving reported signal strengths or other attachment indicator values from a mobile station. The reported signal strengths are compared with characteristic received signal strength values in a coverage area of a mobile network. A mobile switching center determines if a local function is requested and initiates a location estimation process by a mobile location module (MLM). The MLM receives the reported signal strength contours associated with the attachment points. Based on a comparison of the reported attachment indicator values with characteristic values, the MLM provides a mobile location estimate.

Claims

1. A method, for determining a location of a mobile communication device in a network service area when a quality of locating signals is not stable, comprising:

obtaining, from a locating unit, periodically, instantaneous location coordinates corresponding to the mobile communication device;

calculating, by a processor in the mobile communication device, average location coordinates corresponding to a sliding time window over a plurality of time periods;

calculating, by the processor, for the sliding time window over the time periods, error values indicating deviations between the instantaneous location coordinates and the average location coordinates;

determining, by the processor, for the sliding time window over the time periods, peak error values; and

determining, by the processor, for the sliding time window over the time periods, the location of the mobile communication device based at least in part on the instantaneous location coordinates if the peak error values are within pre-defined threshold.

2. The method of claim 1, further comprising determining, by the processor, for the sliding tune window over the time periods, the location of the mobile communication device based at least in part on stored location coordinates if the peak error values are not within pre-defined thresholds.

3. The method of claim 1, further comprising storing, by the processor, the instantaneous location coordinates as stored location coordinates if the peak error values are within the pre-defined threshold.

4. The method of claim 1, wherein largest values among the error values in the sliding time window are chosen as the peak error values.

5. A method, for determining a location of a mobile communication device when a quality of locating signals is not stable, comprising:

defining, by a processor in the mobile communication device, a first zone and a second zone, the first zone being a coverage area of a cell serving the mobile communication device, the second zone being defined based on strength of signals received from the cell and from two adjacent cells;

obtaining, from a locating unit, periodically, instantaneous location coordinates for the mobile communication device;

calculating, by the processor, average location coordinates corresponding to a sliding time window over a plurality of time periods;

calculating, by the processor, for the sliding time window, error values indicating deviations between the instantaneous location coordinates and the average location coordinates;

determining, by the processor, for the sliding time window, peak error values;

determining, by the processor, if the peak error values are within pre-defined threshold, whether the instantaneous location coordinates define a location within the first zone;

determining, by the processor, if the instantaneous location coordinates are within the first zone, whether the instantaneous location coordinates define a location within the second zone; and

determining, by the processor, if the instantaneous location coordinates are within the second zone, in association with a high level of confidence that the instantaneous location coordinates represent the location of the mobile communication device.

6. The method of claim 5, further comprising determining, by the processor, if the instantaneous location coordinates do not defined a location within the second zone, in association with a moderate level of confidence that the instantaneous location coordinates represent the location of the mobile communication device.

7. The method of claim 5, further comprising determining, by the processor, if the instantaneous location coordinates do not defined a location within the first zone, in association with a moderate level of confidence that the second zone represents the location of the mobile communication device.

8. The method of claim 5, further comprising:

determining, if the peak error values do not defined a location within pre-defined thresholds, whether stored location coordinates define a location within the first zone;

determining, if the stored location coordinates define a location within the first zone, whether the stored location coordinates define a location within the second zone; and

determining, if the stored location coordinates define a location within the second zone, in association with a high level of confidence that the stored location coordinates represent the location of the mobile communication device.

9. The method of claim 8, further comprising, determining, if the stored location coordinates do not define a location within the second zone, in association with a moderate level of confidence that the stored location coordinates represent the location of the mobile communication device.

10. The method of claim 8, further comprising determining, if the stored location coordinates do not define a location within the first zone, in association with a low level of confidence that the second zone represents the location of the mobile communication device.

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

a processor; and

a tangible computer-readable storage device having computer-executable instructions that, when executed by the processor, cause the processor to perform operations comprising;

defining a first zone and a second zone, the first zone being a coverage area of a cell serving the mobile communication device, the second zone being defined based on strength of signals received from the cell and from two adjacent cells;

obtaining, periodically, instantaneous location coordinates corresponding to the mobile communication device;

calculating average location coordinates corresponding to a sliding time window over a plurality of time periods;

calculating for the sliding time window over the time periods, error values indicating deviations between the instantaneous location coordinates and the average location coordinates;

determining for the sliding time window over the time periods, peak error values;

determining, if the peak error values are within pre-defined thresholds, whether the instantaneous location coordinates define a location within the first zone;

determining, if the instantaneous location coordinates are within the first zone, whether the instantaneous location coordinates define a location within the second zone; and

determining, if the instantaneous location coordinates are within the second zone, in association with a high level of confidence that the instantaneous location coordinates represent the location of the mobile communication device.

12. The location system of claim 11, wherein the operations further comprise determining, if the instantaneous location coordinates do not defined a location within the second zone, in association with a moderate level of confidence that the instantaneous location coordinates represent the location of the mobile communication device.

13. The location system of claim 11, wherein the operations further comprise determining, if the instantaneous location coordinates do not define a location within the first zone, in association with a moderate level of confidence that the second zone represents the location of the mobile communication device.

14. The location system of claim 11, wherein the operations further comprise:

determining, if the peak error values do not defined a location within pre-defined thresholds, whether stored location coordinates define a location within the first zone;

determining, if the stored location coordinates define a location within the first zone, whether the stored location coordinates define a location within the second zone; and

determining, if the stored location coordinates define a location within the second zone, in association with a high level of confidence that the stored location coordinates represent the location of the mobile communication device.

15. The location system of claim 14, wherein the operations further comprise determining, if the stored location coordinates do not define a location within the second zone, in association with a moderate level of confidence that the stored location coordinates represent the location of the mobile communication device.

16. The location system of claim 14, wherein the operations further comprise determining, if the stored location coordinates do not define a location within the first zone, in association with a low level of confidence that the second zone represents the location of the mobile communication device.

17. The location system of claim 11, wherein largest values among the error values in the sliding time window are chosen as the peak error values.

18. A tangible computer-readable storage device comprising instructions that, when executed by a processor, cause the processor to perform operations, for determining a location of a mobile communication device, comprising:

obtaining, from a locating unit, periodically, instantaneous location coordinates for the mobile communication device;

calculating an average location coordinates corresponding to a sliding time window over a plurality of time periods;

calculating, for the sliding time window over the time periods, error values indicating deviations between the instantaneous location coordinates and the average location coordinates;

determining, for the sliding time window over the time periods, peak error values; and

determining, for the sliding time window over the time periods, the location of the mobile communication device based at least in part on the instantaneous location coordinates if the peak error values are within pre-defined thresholds.

19. The method of claim 18, further comprising determining, for the sliding time window over the time periods, the location of the mobile communication device based at least in part on stored location coordinates if the peak error values are not within pre-defined thresholds.

20. The method of claim 18, further comprising storing the instantaneous location coordinates as stored location coordinates if the peak error values are within pre-defined thresholds.