Johnson Controls Technology Company

Prince Corporation

Johnson Controls Gmbh

Jeffrey N Parks

Thomas R Olson

David J Slater

Paul S Vanlente

The compass system of the present invention utilizes an improved calibration route 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 x+y+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 (&#x2212;A/2, &#x2212;B/2).

Vehicle compass system with continuous automatic calibration

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 x+y+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 (&#x2212;A/2, &#x2212;B/2).

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 x+y+Ax+By+C=for A, B, and C, using the coordinate values (x,y) for the three data points and defining the center point as (&#x2212;A/2, &#x2212;B/2).

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 x+y+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 (&#x2212;A/, &#x2212;B/).

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 &plus;y &plus;Ax&plus;By&plus;C&equals;0 for A, B, and C, using the coordinate values (x,y) for the three data points and defining the center point as (&minus;A/2, &minus;B/2).

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 x,&plus;y,&plus;Ax&plus;By&plus;C&equals;0 for A, B, and C, using the coordinate values (x,y) for the three data points and defining the center point as (&minus;A/2, &minus;B/2).

An electrical system providing automatic calibration of a vehicle compass for abrupt and significant changes in vehicle magnetism. The system includes a magnetic field sensor providing signal information representing the magnetic field sensed within the vehicle. Coupled to the sensor is an electrical circuit for processing the signal information from the sensor to determine if a shift in vehicle magnetism has occurred and for calculating compensation signal information to provide a corrected heading display.

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Holland, MI, United States of America

Jeffrey N Parks