Vehicle compass system with continuous automatic calibration
First Claim
1. A method for calibrating an electronic vehicular compass, comprising:
- receiving electronic data from a sensor circuit in the vehicle, the sensor circuit configured to measure an effect of the earth'"'"'s magnetic field;
calculating deviation compensation data based on a plurality of data points obtained based on data received from the sensor circuit, the plurality of data points comprising a first data point and a second data point; and
determining to use the second data point to calculate deviation compensation data based on a criteria that the second data point is a minimum distance from the first data point;
wherein the minimum distance is variable.
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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).
101 Citations
20 Claims
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1. A method for calibrating an electronic vehicular compass, comprising:
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receiving electronic data from a sensor circuit in the vehicle, the sensor circuit configured to measure an effect of the earth'"'"'s magnetic field;
calculating deviation compensation data based on a plurality of data points obtained based on data received from the sensor circuit, the plurality of data points comprising a first data point and a second data point; and
determining to use the second data point to calculate deviation compensation data based on a criteria that the second data point is a minimum distance from the first data point;
wherein the minimum distance is variable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10, 11)
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9. A method for calibrating an electronic vehicular compass, comprising:
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receiving electronic data from a sensor circuit in the vehicle, the sensor circuit configured to measure an effect of the earth'"'"'s magnetic field;
obtaining a plurality of data points based on data received from the sensor, the plurality of data points comprising a first data point, a second data point, a third data point, and a fourth data point;
determining whether the first data point, second data point, third data point, and fourth data point meet a criteria, the criteria comprising that the evaluated data point is a minimum distance from other data points of the plurality of data points; and
calculating deviation compensation data based on the determination.
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12. A method for calibrating an electronic vehicular compass, comprising:
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receiving electronic data from a sensor circuit in the vehicle, the sensor circuit configured to measure an effect of the earth'"'"'s magnetic field;
calculating deviation compensation data based on a plurality of data points obtained based on data received from the sensor circuit, the plurality of data points comprising a first data point and a second data point; and
determining to use the second data point to calculate deviation compensation data based on a criteria that the second data point is a minimum distance from the first data point, and based on a determination that suggests that a noise level that interferes with data received from the sensor is low. - View Dependent Claims (13, 14, 15, 16)
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17. A method for calibrating an electronic vehicular compass, comprising:
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receiving electronic data from a sensor circuit in the vehicle, the sensor circuit configured to measure an effect of the earth'"'"'s magnetic field;
obtaining a plurality of data points based on data received from the sensor circuit, the plurality of data points comprising a first data point and a second data point;
determining to use the first data point to calculate deviation compensation data;
determining to use the second data point to calculate deviation compensation data based on a criteria that the second data point is a minimum distance from the first data point; and
calculating new deviation compensation data based on old deviation compensation data and the plurality of data points. - View Dependent Claims (18, 19, 20)
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Specification