Methods and apparatus for automatic magnetic compensation
First Claim
1. A method for characterizing distortions in the earth'"'"'s magnetic field caused by a vehicle, a magnetic detection device affixed to the vehicle, said method comprising:
- repeatedly measuring the distorted magnetic field utilizing the magnetic detection device;
obtaining a heading of the vehicle axes with respect to the earth at a time corresponding to each magnetic field measurement;
receiving undistorted earth magnetic field data for the vicinity of the vehicle relative to the earth at the time of each magnetic field measurement; and
utilizing the magnetic field measurements, a true heading of the vehicle, and the undistorted earth magnetic field data to characterize distortions caused by one or more of the vehicle and magnetic detection device errors.
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Abstract
A method for characterizing distortions in the earth'"'"'s magnetic field caused by a vehicle having a magnetometer affixed therein is described. The method includes repeatedly measuring the distorted magnetic field utilizing the magnetometer and obtaining a three-dimensional orientation of the vehicle axes with respect to the earth at a time of each magnetometer measurement. The method also includes receiving undistorted earth magnetic field data for the vicinity of the vehicle relative to the earth at the time of each magnetometer measurement and characterizing distortions caused by one or more of the vehicle and magnetometer errors utilizing the magnetic field measurements, the orientations of the vehicle, and the undistorted earth magnetic field data.
65 Citations
22 Claims
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1. A method for characterizing distortions in the earth'"'"'s magnetic field caused by a vehicle, a magnetic detection device affixed to the vehicle, said method comprising:
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repeatedly measuring the distorted magnetic field utilizing the magnetic detection device; obtaining a heading of the vehicle axes with respect to the earth at a time corresponding to each magnetic field measurement; receiving undistorted earth magnetic field data for the vicinity of the vehicle relative to the earth at the time of each magnetic field measurement; and utilizing the magnetic field measurements, a true heading of the vehicle, and the undistorted earth magnetic field data to characterize distortions caused by one or more of the vehicle and magnetic detection device errors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A magnetic compass compensation unit for characterizing distortions in the earth'"'"'s magnetic field caused by a vehicle in which said unit is mounted, the distortions relative to an undisturbed magnetic field of the earth, said unit comprising:
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a magnetic detection device; and a processor configured to receive measurements of the distorted magnetic field from said magnetic detection device, obtain a heading of the vehicle axes with respect to the earth at a time corresponding to each said magnetic detection device measurement, receive undistorted earth magnetic field data for the vicinity of the vehicle relative to the earth at the time corresponding to each said magnetic detection device measurement, and characterize the distortions utilizing the magnetic field measurements, true heading of the vehicle, and the undistorted earth magnetic field data. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for determining a true earth magnetic field from a magnetic field measured by a magnetic detection device, said method comprising:
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generating a truth reference field vector from sources of pitch, roll, heading, and position independent of the magnetic detection device and a map of the earth'"'"'s magnetic field; determining a difference between a vector as measured by the magnetic detection device and the truth reference vector; and utilizing the difference to estimate corrections to model coefficients. - View Dependent Claims (22)
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Specification