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US 7,921,572 B2Granted
Accuracy indications for an electronic compass in a portable device
AssigneeApple Inc.
InventorsRobert Mayor, Patrick S. Piemonte, Ronald K. Huang, Parin Patel
Life of this patent
Estimating the term…
Abstract
Multiple instances of a geomagnetic field are calculated. Multiple instances of an average magnitude of a subset of the instances of the geomagnetic field are also calculated. When the average magnitude changes by more than a first predetermined threshold, the user is informed that compass accuracy has degraded. Other embodiments are also described and claimed.
Claims20
A machine-implemented method for providing a user with accuracy indications for a compass, comprising:
- calculating a first plurality of instances of a geomagnetic field;
- calculating a second, different plurality of instances of the geomagnetic field;
- calculating an average magnitude of the first plurality of instances of the geomagnetic field;
- calculating an average magnitude of the second plurality of instances of the geomagnetic field;
- detecting whether the average magnitudes of the first plurality of instances and the second plurality of instances differ by more than a first predetermined threshold;
- and
- informing the user that compass accuracy has degraded, in response to having detected that the average magnitudes differ by more than the first predetermined threshold.
4 more elements
A portable device comprising:
- a portable device housing having integrated therein
- a magnetic sensor;
- a compass calibrator to compute a plurality of instances of a geomagnetic field based on an observed magnetic field and an estimated magnetic interference field;
- a compass accuracy indicator module to calculate a plurality of instances of an average magnitude of a subset of the plurality of instances of the geomagnetic field, and to detect whether the average magnitude changes by more than a predetermined threshold;
- and
- a user interface module coupled to drive one of a speaker and a display screen of the portable device, wherein the compass accuracy indicator module is to use the user interface module to inform a user of the portable device that compass accuracy has degraded in response to having detected that the average magnitude has changed by more than the predetermined threshold.
3 more elements
An article of manufacture comprising:
- a non-transitory machine-readable medium having stored therein instructions that program a processor, of a portable device having an integrated magnetic sensor, to compute a plurality of instances of a geomagnetic field using the magnetic sensor, calculate a plurality of instances of an average magnitude of a subset of the plurality of instances of the geomagnetic field, detect whether the average magnitude changes by more than a predetermined threshold, and signal a user interface module of the portable device that compass accuracy has degraded in response to having detected that the average magnitude has changed by more than the predetermined threshold.
A machine-implemented method for providing a user with accuracy indications for a compass, comprising:
- calculating a first set of two or more instances of a geomagnetic field;
- calculating a second, different set of two or more instances of the geomagnetic field;
- calculating an average magnitude of the first set of two or more instances of the geomagnetic field;
- calculating an average magnitude of the second set of two or more instances of the geomagnetic field;
- detecting whether a difference between the average magnitudes of the first set and second set exceeds a first predetermined threshold;
- and
- informing the user that compass accuracy has degraded, in response to having detected that the difference between the average magnitudes has exceeded the first predetermined threshold.
4 more elements
A machine-implemented method for providing a user with accuracy indications for a compass, comprising:
- calculating a plurality of instances of a geomagnetic field;
- calculating a magnitude for each instance of the geomagnetic field;
- maintaining a moving average of the magnitudes of the plurality of instances of the geomagnetic field;
- detecting whether the moving average changes by more than a first predetermined threshold;
- and
- informing the user that compass accuracy has degraded, in response to having detected that the moving average has changed by more than the first predetermined threshold.
3 more elements
Dependencies are inferred from the claim text.