System and method for calibrating a magnetometer according to a quality threshold

• US 8,922,198 B2
• Filed: 09/19/2011
• Issued: 12/30/2014
• Est. Priority Date: 10/26/2010
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Almalki, Nazih, Snow, Christopher Harris, Dods, Jeffrey Alton Hugh, Parco, Adam Louis
• Primary Examiner(s): LEDYNH, BOT L
• Application Number:
  US13/235,824
• Publication Number:
  US 20120096921A1
• Time in Patent Office: 1,198 Days
• Field of Search: 324/202
• US Class Current: 324/202
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses
• CPC Class Codes: G01R 33/0023 Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration G01R33/0017 takes precedence
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence
• CPC Class Codes: H04M 1/0214 Foldable telephones, i.e. with body parts pivoting to an open position around an axis parallel to the plane they define in closed position combined with translation movement H04M1/0235
• CPC Class Codes: H04M 1/72427 for supporting games or graphical animations
• CPC Class Codes: H04M 1/72454 according to context-related or environment-related conditions
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion telephones including GPS signal receivers H04M2250/10

Abstract

A method and system are provided for calibrating a magnetometer. The method comprises determining a current quality level associated with magnetometer readings obtained using an active set of calibration parameters; and lowering a quality threshold for a background calibration of the magnetometer when the current quality level exceeds a threshold quality level needed by an application utilizing the magnetometer readings.

Claims

1. A method of calibrating a magnetometer on a mobile device, the method comprising:

determining a current quality level associated with magnetometer readings obtained using an active set of calibration parameters; and

lowering a quality threshold for a background calibration of the magnetometer when the current quality level exceeds a threshold quality level needed by an application utilizing the magnetometer readings.

2. The method according to claim 1, wherein lowering the quality threshold prevents an ongoing background calibration from attempting to achieve a higher quality level.

3. The method according to claim 1, wherein the threshold quality level needed by the application is provided in an instruction from the application to calibrate the magnetometer.

4. The method according to claim 3, wherein the instruction is associated with an absence of calibration parameters for the magnetometer.

5. The method according to claim 1, further comprising initiating a foreground calibration of the magnetometer if the threshold quality level needed by the application is higher than the current quality level.

6. The method according to claim 1, wherein the application is any one of a digital compass application, a stud-finder application, and an augmented reality based application.

7. A non-transitory computer readable medium comprising computer executable instructions for calibrating a magnetometer on a mobile device, the computer readable medium comprising instructions for:

determining a current quality level associated with magnetometer readings obtained using an active set of calibration parameters; and

lowering a quality threshold for a background calibration of the magnetometer when the current quality level exceeds a threshold quality level needed by an application utilizing the magnetometer readings.

8. The non-transitory computer readable medium according to claim 7, wherein lowering the quality threshold prevents an ongoing background calibration from attempting to achieve a higher quality level.

9. The non-transitory computer readable medium according to claim 7, wherein the threshold quality level needed by the application is provided in an instruction from the application to calibrate the magnetometer.

10. The non-transitory computer readable medium according to claim 9, wherein the instruction is associated with an absence of calibration parameters for the magnetometer.

11. The non-transitory computer readable medium according to claim 7, further comprising instructions for initiating a foreground calibration of the magnetometer if the threshold quality level needed by the application is higher than the current quality level.

12. The non-transitory computer readable medium according to claim 7, wherein the application is any one of a digital compass application, a stud-finder application, and an augmented reality based application.

13. A mobile device comprising a processor coupled to a memory, and a magnetometer, the memory comprising computer executable instructions for:

determining a current quality level associated with magnetometer readings obtained using an active set of calibration parameters; and

lowering a quality threshold for a background calibration of the magnetometer when the current quality level exceeds a threshold quality level needed by an application utilizing the magnetometer readings.

14. The mobile device according to claim 13, wherein lowering the quality threshold prevents an ongoing background calibration from attempting to achieve a higher quality level.

15. The mobile device according to claim 13, wherein the threshold quality level needed by the application is provided in an instruction from the application to calibrate the magnetometer.

16. The mobile device according to claim 15, wherein the instruction is associated with an absence of calibration parameters for the magnetometer.

17. The mobile device according to claim 13, further comprising initiating a foreground calibration of the magnetometer if the threshold quality level needed by the application is higher than the current quality level.

18. The mobile device according to claim 13, wherein the application is any one of a digital compass application, a stud-finder application, and an augmented reality based application.