Estimating and predicting structures proximate to a mobile device

• US 9,817,125 B2
• Filed: 09/07/2012
• Issued: 11/14/2017
• Est. Priority Date: 09/07/2012
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Liu, Jie, Zhong, Lin, Chu, David, Sidhu, Gursharan, Priyantha, Nissanka Arachchige Bodhi, Agarwal, Sharad
• Primary Examiner(s): Issing, Gregory C
• Application Number:
  US13/606,029
• Publication Number:
  US 20140070991A1
• Time in Patent Office: 1,894 Days
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/39 the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
• CPC Class Codes: G01S 19/428 using multipath or indirect path propagation signals in position determination

Abstract

The description relates to mobile device location. One example can identify global navigation satellite system (GNSS) satellites expected to be in line-of-sight of a mobile device. This example can detect differences between received GNSS data signals and expected GNSS data signals from the expected GNSS satellites. The example can also determine a direction from the mobile device of an obstruction that is causing at least some of the detected differences.

Claims

1. A method comprising:

approximating a location of a mobile device based at least upon a last accurate global navigation satellite system (GNSS) reading associated with actual GNSS data received by the mobile device, the actual GNSS data being sensed according to a predetermined default setting;

identifying expected GNSS data from a set of GNSS satellites that should be in line of sight to the mobile device based at least upon the last accurate GNSS reading and ephemeris information;

detecting differences between the expected GNSS data and the actual GNSS data received by the mobile device;

distinguishing between at least one unobstructed GNSS satellite and at least one obstructed GNSS satellite using the differences, the at least one unobstructed GNSS satellite having corresponding actual GNSS data that matches the expected GNSS data and the at least one obstructed GNSS satellite having associated actual GNSS data that does not match the expected GNSS data;

recognizing that a geographic feature is proximate to the mobile device and that the geographic feature is located in the direction of the at least one obstructed GNSS satellite;

predicting effects of the geographic feature on the mobile device at a subsequent time; and

sensing the actual GNSS data more frequently than the predetermined default setting based at least in part on the predicted effects of the geographic feature.

2. The method of claim 1, wherein the identifying comprises obtaining the ephemeris information from the set of GNSS satellites.

3. The method of claim 1, further comprising:

based at least on the differences between the expected GNSS data and the actual GNSS data, determining that the mobile device is in a penumbral region created by the geographic feature.

4. The method of claim 1, wherein the detecting comprises comparing signal strengths of the actual GNSS data to a signal strength threshold, the corresponding actual GNSS data for the at least one unobstructed GNSS satellite exceeding the signal strength threshold and the associated actual GNSS data for at least one obstructed GNSS satellite falling below the signal strength threshold.

5. The method of claim 1, further comprising:

determining that the mobile device is on a particular side of a street that is relatively closer to the geographic feature than another side of the street.

6. The method of claim 1, wherein the predicting comprises:

predicting whether the mobile device will enter an umbral region created by the geographic feature.

7. The method of claim 1, wherein the predicting comprises:

determining whether the mobile device is moving toward the geographic feature, away from the geographic feature, or parallel to the geographic feature.

8. The method of claim 7, further comprising:

activating dead reckoning functionality on the mobile device based at least in part on the predicted effects of the geographic feature.

9. The method of claim 7, wherein the predicting comprises:

in an instance when the mobile device is moving toward the geographic feature, predicting a time when the mobile device will clear the geographic feature and be able to accurately determine a subsequent location of the mobile device.

10. The method of claim 9, further comprising:

determining a size and relative location of the geographic feature and a direction and velocity of the mobile device,

wherein the time is predicted based at least on the size, the relative location, the direction, and the velocity.

11. The method of claim 1, further comprising:

in at least one instance, determining a path of the mobile device from the location.

12. The method of claim 1, performed entirely by the mobile device.

13. A mobile device comprising:

a processor; and

hardware storage storing instructions which, when executed by the processor, configure the processor to;

approximate a location of the mobile device based at least upon a last accurate global navigation satellite system (GNSS) reading associated with actual GNSS data received by the mobile device according to a periodic setting;

identify expected GNSS data from a set of GNSS satellites that are expected to be in line of sight to the mobile device based at least upon the last accurate GNSS reading;

detect differences between the expected GNSS data and the actual GNSS data received by the mobile device to identify at least one obstructed GNSS satellite having associated actual GNSS data that does not match the expected GNSS data;

recognize that a geographic feature is proximate to the mobile device and that the geographic feature is located in the direction of the at least one obstructed GNSS satellite; and

responsive to recognizing that the geographic feature is proximate to the mobile device, receive the actual GNSS data more frequently than the periodic setting.

14. The mobile device of claim 13, wherein the instructions, when executed by the processor, configure the processor to:

determine a refined location of the mobile device that is relatively closer to the geographic feature than the location approximated using the last accurate GNSS reading.

15. The mobile device of claim 14, wherein the instructions, when executed by the processor, configure the processor to:

responsive to recognizing that the at least one obstructed GNSS satellite is to the North of the mobile device, determine the refined location such that the refined location is to the North of the location approximated using the last accurate GNSS reading.

16. The mobile device of claim 13, wherein the instructions, when executed by the processor, configure the processor to:

responsive to recognizing that the geographic feature is proximate to the mobile device, control the mobile device by activating a relative location mechanism on the mobile device.

17. The mobile device of claim 16, wherein the relative location mechanism comprises a dead reckoning mechanism.

18. A system comprising:

a processor; and

hardware storage storing instructions which, when executed by the processor, configure the processor to;

approximate a location of a mobile device based at least upon a last accurate global navigation satellite system (GNSS) reading associated with actual GNSS data received by the mobile device according to a predetermined setting;

identify expected GNSS data from a set of GNSS satellites that should be in line of sight to the mobile device based at least upon the last accurate GNSS reading;

detect differences between the expected GNSS data and the actual GNSS data received by the mobile device;

based at least on the detected differences between the expected GNSS data and the actual GNSS data, determine that there is at least one obstructed GNSS satellite at the location of the mobile device; and

responsive to determining that there is at least one obstructed GNSS satellite at the location of the mobile device, cause the mobile device to receive the actual GNSS data more frequently than the predetermined setting.

19. The system of claim 18, embodied as a computer located remotely from the mobile device.

20. The system of claim 18, embodied as the mobile device.