Estimating network based locating error in wireless networks

• US 9,519,043 B2
• Filed: 07/21/2011
• Issued: 12/13/2016
• Est. Priority Date: 07/21/2011
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Fix, Jeremy, Kosseifi, Mario, Meredith, Sheldon
• Primary Examiner(s): Issing, Gregory C
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US13/188,136
• Publication Number:
  US 20130021199A1
• Time in Patent Office: 1,972 Days
• Field of Search: 342/450, 342463-465, 342/357.31, 73/17.9
• US Class Current: 1/1
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence

Abstract

Systems and techniques for determining the accuracy of network based user equipment (UE) locating methods and results thereof are disclosed. Periodic direct measurements of location error for a network based location result are determined by the difference in the network based location result and an assisted global positioning system (AGPS) location result. The location error is associated with a cell-pair contributing to data employed to determine the network based location result. The error associated with the cell-pair is then applied as a measure of accuracy in future network based location results that also employ data associated with the cell-pair to determine the future network based location result.

Claims

1. A method, comprising:

issuing, by a system comprising a processor, a command for a first mobile device to perform an assisted global positioning system location determination;

receiving, by the system, a response from the first mobile device comprising a result of the assisted global positioning system location determination and a first time at which the result was determined by the first mobile device;

receiving, by the system, reports from mobile devices comprising signal information indicating arrival times of signals that were respectively received by the mobile devices from three base station devices;

identifying, by the system, a first report of the reports comprising first signal information indicating first arrival times of first signals that were received by the first mobile device from the three base station devices at the first time, and based on the identifying;

determining, by the system, first observed time difference of arrival measurements for respective pairs of the three base station devices based on the first signal information;

determining, by the system, an approximate location of the first mobile device at the first time based on the first observed time difference of arrival measurements;

determining, by the system, first error values respectively associated with the first observed time difference of arrival measurements based on a difference between the approximate location and the result of the global positioning system location determination;

storing, by the system, error information respectively associating the first error values with the respective pairs of the three base station devices; and

employing the first error values to calibrate a subsequent approximate location determination for the first mobile device based on a second observed time difference of arrival measurement determined for the respective pairs of the three base station devices.

2. The method of claim 1, wherein the determining the approximate location of the first mobile device includes employing timed fingerprinting.

3. The method of claim 1, wherein the the response is included in a radio resource control report received from the first mobile device.

4. The method of claim 1, wherein the reports comprise radio access network application part reports.

5. The method of claim 1, further comprising:

employing, by the system, the first errors values to calibrate a subsequent approximate location determination for a second mobile device based on a third observed time difference of arrival measurement determined for the respective pairs of the three base station devices.

6. The method of claim 1, wherein the receiving the first report and the second report is based on the first mobile device being in an active CELL_DCH state.

7. The method of claim 1, wherein the assisted global positioning system location determination was made by the first mobile device at the first time based on the issuing of the command.

8. A method, comprising:

sending, by a system comprising a processor, a request to a first mobile device to perform an assisted global positioning system location determination for the mobile device;

receiving, by the system, a response from the first mobile device comprising a result of the assisted global positioning system location determination and a first time at which the result was determined by the first mobile device;

receiving, by the system, reports from mobile devices comprising signal information indicating arrival times of signals that were respectively received by the mobile devices from three base station devices;

identifying, by the system, a first report of the reports comprising first signal information indicating first arrival times of first signals that were received by the first mobile device from the three base station devices at substantially the first time, and based on the at the first time identifying;

determining, by the system, first observed time difference of arrival measurements for respective pairs of the three base station devices based on the first signal information;

determining, by the system, an approximate location of the first mobile device at the first time based on the first observed time difference of arrival measurements;

determining, by the system, first error values respectively associated with the first observed time difference of arrival measurements based a difference between the approximate location and the location determined according to the assisted global positioning system location determination;

storing, by the system, error information respectively associating the first error values with the respective pairs of the three base station devices; and

employing, by the system, a first error value of the first error values associated with a first pair of the respective pairs of the three base station devices to calibrate a subsequent approximate location determination for a second mobile device based on a second observed time difference of arrival measurement determined for the first pair of the respective pairs of the three base station devices.

9. The method of claim 8, further comprising:

determining, by the system, a median error value for the first pair of the respective pairs of the three base station devices based on error values comprising the first error value and additional error values respectively associated with the first pair of the respective pairs of the three base station devices.

10. The method of claim 9, further comprising:

determining, by the system, a set of the error values associated with the first pair of the respective pairs of the three base station devices that constitute outliers based on the median error; and

disassociating, by the system, the set of the error values that constitute the outliers from the first pair of the respective pairs of the three base station devices.

11. The method of claim 8, wherein the determining the approximate location of the first mobile device includes employing timed fingerprinting.

12. The method of claim 8, wherein the is included in a radio resource control report provided by the first mobile device.

13. The method of claim 8, wherein the reports comprise radio access network application part reports.

14. The method of claim 8, further comprising:

employing, by the system, the first error value to calibrate a subsequent approximate location determination for the first mobile device based on a third observed time difference of arrival measurement determined for the first pair of the respective pairs of the three base station devices.

15. The method of claim 8, wherein the assisted global positioning system location determination was made by the first mobile device at the first time based on the sending of the request.

16. A non-transitory machine-readable storage medium comprising executable instructions that, when executed by a processor, facilitate performance of operations, comprising:

commanding mobile devices to perform assisted global positioning system location determinations;

receiving responses from the mobile device comprising results of the assisted global positioning system location determinations and first times at which the results were respectively determined by the mobile devices;

receiving reports from the mobile devices comprising signal information indicating arrival times of signals that were respectively received by the mobile devices from three base station devices;

identifying a group of the reports of the reports comprising first signal information indicating arrival times of signals that were received by respective ones of the mobile devices from the three base station devices at or near the first times, and based on the at the first time identifying;

determining first observed time difference of arrival measurements for respective pairs of the three base station devices based on the first signal information;

determining first locations of the respective ones of the mobile devices at the first times based on the observed time difference of arrival measurements;

determining errors respectively associated with the first observed time difference of arrival measurements based on comparison of the first locations and the results of the assisted global positioning system location determinations for the respective ones of the mobile devices; and

storing information respectively associating the errors with the respective pairs of the three base station devices; and

employing the errors to calibrate a subsequent approximate location determination for a mobile device other than the mobile devices based on a second observed time difference of arrival measurement determined for the respective pairs of the three base station devices.

17. The non-transitory machine-readable storage medium of claim 16, the operations further comprising:

determining mean error rates for the respective pairs of the three base station devices based on the errors respectively associated therewith; and

employing the mean error rates to calibrate the subsequent approximate location determination for the mobile device based on the second observed time difference of arrival measurements.

18. The non-transitory machine-readable storage medium of claim 16, wherein the respective ones of the mobile devices performed the assisted global positioning system location determinations at the first times based on the commanding.