OPPORTUNISTIC CALIBRATION OF A BAROMETER IN A MOBILE DEVICE

• US 20150247917A1
• Filed: 02/26/2015
• Published: 09/03/2015
• Est. Priority Date: 02/28/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gum, Arnold Jason, Moeglein, Mark Leo
• Granted Patent: US 10,094,905 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: H04W 4/025 using location based information parameters
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 4/40 for vehicles, e.g. vehicle-to-pedestrians [V2P]

Abstract

Disclosed are systems, methods and techniques for calibrating an altimeter of a mobile device. For example, a characterized motion of a mobile device may be used to infer an altitude of the mobile device. If it is further inferred that the mobile device is in an outdoor environment, an altitude of the mobile device may be based on application of an estimated location of the mobile device to an altitude terrain map.

Claims

1. A method comprising, at a mobile device :

determining that said mobile device is located in an outdoor environment at a ground level;

determining that said mobile device is located at a discernible altitude level based, at least in part, on;

(i) a signal obtained from a sensor onboard said mobile device;

(ii) an electronic map indicative of a local terrain;

or (iii) a combination of (i) and (ii); and

in response to an estimation that said mobile device is at said discernible altitude level, initiating a calibration process of a barometer onboard said mobile device, said calibration process to identify a reference atmospheric pressure for said discernible altitude level.

2. The method as recited in claim 1, wherein determining that said mobile device is located at said discernable altitude level further comprises:

determining an estimated horizontal location of said mobile device based, at least in part, on one or more signals obtained from said sensor onboard said mobile device; and

applying said electronic map indicative of said local terrain to said estimated horizontal location to determine an estimated altitude of said mobile device.

3. The method as recited in claim 2, wherein determining that said mobile device is located at said discernable altitude level further comprises:

estimating an error in said estimated altitude; and

determining said discernable altitude level as said estimated altitude if said estimated error is less than a threshold value.

4. The method as recited in claim 1, wherein determining that said mobile device is located at said discernable altitude level further comprises:

estimating that said mobile device is at said discernible altitude level, is based, at least in part, on an estimated movement routine corresponding to said mobile device.

5. The method as recited in claim 1, wherein determining that said mobile device is located at said discernable altitude level further comprises:

estimating that said mobile device is in motion at said discernible altitude level, based, at least in part, on a wireless signal acquired from a transmitting device.

6. The method as recited in claim 1, wherein determining that said mobile device is located in said outdoor environment at said ground level further comprises inferring that said mobile device is on said ground level based, at least in part, on an estimated motion speed of the mobile device, and wherein determining that said mobile device is located at the discernable altitude level further comprises:

determining an altitude of said ground level based, at least in part, on said electronic map indicative of said local terrain.

7. The method as recited in claim 6, and further comprising, at said mobile device:

obtaining a history of detected movements suggestive of travelling over a particular outdoor contour of said local terrain.

8. The method as recited in claim 1, and further comprising, at said mobile device:

identifying;

(1) an altitude uncertainty value corresponding to said discernible altitude level;

(2) a reference pressure uncertainty value corresponding to said reference atmospheric pressure;

or (3) both (1) and (2).

9. The method as recited in claim 1, and further comprising, at said mobile device:

transmitting a message to another device, said message being indicative of said discernible altitude level and said reference atmospheric pressure.

10. The method as recited in claim 1, and further comprising, at said mobile device:

maintaining a calibration history corresponding to a plurality of completed calibration operations, said calibration history being indicative of at least a plurality of estimated discernible altitude levels, times of said plurality of completed calibration operations or reference atmospheric pressure values corresponding to said completed calibration operations, or any combination thereof.

11. An apparatus for use in a mobile device, the apparatus comprising:

means for determining that said mobile device is located in an outdoor environment at a ground level;

means for determining that said mobile device is located at a discernible altitude level based, at least in part, on;

(i) a signal obtained from a sensor onboard said mobile device;

(ii) an electronic map indicative of a local terrain;

or (iii) a combination of (i) and (ii); and

means for initiating a calibration process of a barometer onboard said mobile device in response to an estimation that said mobile device is in motion at said discernible altitude level, said calibration process to identify a reference atmospheric pressure for said discernible altitude level.

12. The apparatus as recited in claim 11, wherein said means for determining that said mobile device is located at said discernable altitude level further comprises:

means for determining an estimated horizontal location of said mobile device based, at least in part, on one or more signals obtained from said sensor onboard said mobile device; and

means for applying said electronic map indicative of said local terrain to said estimated horizontal location to determine an estimated altitude of said mobile device.

13. The apparatus as recited in claim 12, wherein said means for determining that said mobile device is located at said discernable altitude level further comprises:

means for estimating an error in said estimated altitude; and

means for determining said discernable altitude level as said estimated altitude if said estimated error is less than a threshold value.

14. The apparatus as recited in claim 11, wherein said means for determining that said mobile device is located at said discernable altitude level further comprises:

means for estimating that said mobile device is in motion at said discernible altitude level, based, at least in part, on an estimated movement routine corresponding to said mobile device.

15. The apparatus as recited in claim 11, wherein said means for determining that said mobile device is located at said discernable altitude level further comprises:

means for estimating that said mobile device is in motion at said discernible altitude level, based, at least in part, on a wireless signal acquired from a transmitting device.

16. The apparatus as recited in claim 11, and further comprising:

means for maintaining a calibration history corresponding to a plurality of completed calibration operations, said calibration history being indicative of at least a plurality of estimated discernible altitude levels, times of said completed calibration operations or corresponding identified reference atmospheric pressures, or any combination thereof.

17. A mobile device comprising:

a plurality of sensors, wherein at least one of said plurality of sensors comprises a barometer;

memory; and

a processing unit to;

determine that said mobile device is located in an outdoor environment at a ground level;

determine that said mobile device is located at a discernible altitude level based, at least in part, on;

(i) a signal obtained from one of said plurality of sensors;

(ii) an electronic map stored in said memory and which is indicative of a local terrain;

or (iii) a combination of (i) and (ii); and

in response to an estimation that said mobile device is in motion at said discernible altitude level, initiate a calibration process of said barometer, to identify a reference atmospheric pressure for said discernible altitude level.

18. The mobile device as recited in claim 17, said processing unit to further:

determine that said mobile device is in located at said discernible altitude level, based, at least in part, on an estimated horizontal location of said mobile device based, at least in part, on one or more signals obtained from said barometer; and

application of said electronic map indicative of said local terrain to said estimated horizontal location to determine an estimated altitude of said mobile device.

19. The mobile device as recited in claim 18, said processing unit to further:

determine that said mobile device is located at said discernable altitude level based , at least in part, on an estimated error in said estimated altitude being less than a threshold value.

20. The mobile device as recited in claim 17, said processing unit to further:

determine that said mobile device is located at said discernible altitude level, based, at least in part, on an estimated movement routine corresponding to said mobile device.

21. The mobile device as recited in claim 17, and further comprising:

a receiver; and

said processing unit to further;

determine that said mobile device is located at said discernible altitude level, based, at least in part, on a wireless signal acquired from a transmitting device via said receiver.

22. The mobile device as recited in claim 17, said processing unit to further:

determine that said mobile device is located in said outdoor environment at said ground level based, at least in part, on an inference that said mobile device is on said ground level based, at least in part, on an estimated motion speed of the mobile device; and

determine an altitude of said ground level based, at least in part, on said electronic map indicative of said local terrain.

23. The mobile device as recited in claim 17, said processing unit to further:

identify;

(1) an altitude uncertainty value corresponding to said discernible altitude level;

(2) a reference pressure uncertainty value corresponding to said reference atmospheric pressure;

or (3) both (1) and (2).

24. The mobile device as recited in claim 17, said processing unit to further:

maintain a calibration history corresponding to a plurality of completed calibration operations in said memory, said calibration history being indicative of at least a plurality of estimated discernible altitude levels, times of said completed calibration operations or corresponding identified reference atmospheric pressures, or any combination thereof.

25. A non-transitory computer readable medium having stored therein computer implementable instructions executable by a processing unit of a mobile:

determine that said mobile device is located in an outdoor environment at a ground level;

determine that said mobile device is located at a discernible altitude level based, at least in part, on;

(i) a signal obtained from a sensor onboard said mobile device;

(ii) an electronic map indicative of a local terrain;

or (iii) a combination of (i) and (ii); and

initiate a calibration process of a barometer onboard said mobile device in response to an estimation that said mobile device is in motion at said discernible altitude level, said calibration process to identify a reference atmospheric pressure for said discernible altitude level.

26. The non-transitory computer readable medium as recited in claim 25, said computer implementable instructions being further executable by said processing unit of said mobile device to:

determine an estimated horizontal location of said mobile device based, at least in part, on one or more signals obtained from said sensor onboard said mobile device; and

apply said electronic map indicative of said local terrain to said estimated horizontal location to determine an estimated altitude of said mobile device.

27. The non-transitory computer readable medium as recited in claim 26, said computer implementable instructions being further executable by said processing unit of said mobile device to:

determine an estimated error in said estimated altitude; and

determine said discernable altitude level as said estimated altitude if said estimated error is less than a threshold value.

28. The non-transitory computer readable medium as recited in claim 25, said computer implementable instructions being further executable by said processing unit of said mobile device to:

estimate that said mobile device is located at said discernible altitude level, based, at least in part, on an estimated movement routine corresponding to said mobile device.

29. The non-transitory computer readable medium as recited in claim 25, said computer implementable instructions being further executable by said processing unit of said mobile device to:

estimating that said mobile device is located at said discernible altitude level, based, at least in part, on a wireless signal acquired from a transmitting device.

30. The non-transitory computer readable medium as recited in claim 25, said computer implementable instructions being further executable by said processing unit of said mobile device to:

maintain a calibration history corresponding to a plurality of completed calibration operations, said calibration history being indicative of at least a plurality of estimated discernible altitude levels, times of said completed calibration operations or corresponding identified reference atmospheric pressures, or any combination thereof.