Vehicle compass system with continuous automatic calibration
First Claim
1. A method for calibrating an electronic compass, comprising:
- calculating a first averaged data point using a first predetermined number of data points;
calculating a second averaged data point using a second predetermined number of data points;
calculating a third averaged data point;
calculating deviation compensation data based on a combination of the first averaged data point, the second averaged data point, and the third averaged data point;
determining if a vehicle is moving a predetermined speed; and
obtaining data for at least one of the first averaged data point, the second averaged data point, and the third averaged data point based on the determination of vehicle speed.
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Accused Products
Abstract
The compass system of the present invention utilizes an improved calibration routine in which a processing circuit of the compass recalibrates the compass each time three data points are obtained from a magnetic field sensor that meet predetermined criteria. One such criterion is that the three data points define corners of a triangle that is substantially non-obtuse. When three data points have been obtained that define a triangle meeting this criterion, the processing circuit calculates a center point for a circle upon which all three data points lie by solving the equation x2+y2+Ax+By+C=0 for A, B, and C, using the coordinate values (x,y) for the three data points and defining the center point as (−A/2, −B/2).
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Citations
7 Claims
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1. A method for calibrating an electronic compass, comprising:
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calculating a first averaged data point using a first predetermined number of data points;
calculating a second averaged data point using a second predetermined number of data points;
calculating a third averaged data point;
calculating deviation compensation data based on a combination of the first averaged data point, the second averaged data point, and the third averaged data point;
determining if a vehicle is moving a predetermined speed; and
obtaining data for at least one of the first averaged data point, the second averaged data point, and the third averaged data point based on the determination of vehicle speed. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification