The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Mar. 21, 2017

Filed:

May. 04, 2015
Applicant:

Blackberry Limited, Waterloo, CA;

Inventors:

Nazih Almalki, Waterloo, CA;

Robert George Oliver, Waterloo, CA;

Assignee:

BlackBerry Limited, Waterloo, Ontario, CA;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01R 35/00 (2006.01); G01C 19/00 (2013.01); G01R 33/07 (2006.01); G01C 17/38 (2006.01);
U.S. Cl.
CPC ...
G01R 35/005 (2013.01); G01C 17/38 (2013.01); G01C 19/00 (2013.01); G01R 33/07 (2013.01);
Abstract

A method for calibrating a magnetometer following a temperature event is described. The magnetometer includes three sensors, including a Hall Effect sensor associated with a first sensing axis and a sensor of another type associated with a second sensing axis. The method includes: maintaining a cache of gyroscope data and magnetometer data representing magnetometer readings obtained from the magnetometer; detecting a temperature event; determining an expected magnetometer reading following the temperature event; comparing the expected magnetometer reading to a magnetometer reading obtained from the magnetometer after the temperature event to determine a calibration correction amount; compare a difference between the magnetometer reading obtained after the temperature event and the expected magnetometer reading for the second sensing axis to a threshold and, based on the comparison to the threshold, generating new calibration data for the magnetometer based on the calibration correction amount.


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