VEHICLE COMPASS SYSTEM WITH CONTINUOUS AUTOMATIC CALIBRATION
First Claim
1. A compass system configured to operate with a magnetic field sensor configured to provide magnetic field data in response to Earth'"'"'s magnetic field and a global position system configured to receive position data from a positioning satellite, the compass system comprising:
- a processor coupled to the magnetic field sensor and to the global position data, the processor configured to receive the magnetic field data and data from the global positioning system, to process the data to compensate the data, and to provide a heading output based on the compensated data; and
a memory coupled to the microprocessor, the memory configured to store compass compensation data.
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Accused Products
Abstract
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 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
20 Claims
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1. A compass system configured to operate with a magnetic field sensor configured to provide magnetic field data in response to Earth'"'"'s magnetic field and a global position system configured to receive position data from a positioning satellite, the compass system comprising:
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a processor coupled to the magnetic field sensor and to the global position data, the processor configured to receive the magnetic field data and data from the global positioning system, to process the data to compensate the data, and to provide a heading output based on the compensated data; and
a memory coupled to the microprocessor, the memory configured to store compass compensation data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A compass system, comprising:
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a heading indicator configured to provide a heading output;
a magnetic field sensor configured to provide data in response to Earth'"'"'s magnetic field;
a global position system configured to receive position data from a positioning satellite;
a microprocessor coupled to the magnetic field sensor and the global positioning system, the microprocessor configured to receive data from the magnetic field sensor and the global positioning system, to process the data, and to provide a heading output to be displayed by the heading indicator. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A compass system mounted in a vehicle a display configured to provide a heading output data, comprising:
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a magnetic field sensor configured to provide data in response to Earth'"'"'s magnetic field;
a global position system configured to receive position data from a positioning satellite;
a vehicle speed sensor configured to receive data indicative of a speed traveled by the vehicle;
a memory configured to store compass data; and
a processor coupled to the magnetic field sensor, the global positioning system, and the memory, the processor configured to receive data from the magnetic field sensor and the global positioning system and to process the data, the processor further configured to compensate the data from the magnetic field sensor based on compensation data from the memory, the processor still further configured to at least one of calculate compensation data and control a heading to be output based on data from the vehicle speed sensor. - View Dependent Claims (20)
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Specification