AUTOMATICALLY UPDATING HARD IRON AND SOFT IRON COEFFICIENTS OF A MAGNETIC SENSOR
First Claim
1. A method of automatically updating hard iron and soft iron coefficients of a magnetic sensor of a device, comprising:
- making measurements of a magnetic field by the magnetic sensor during rotations of the device;
determining by at least a criterion whether to input the measurements of the magnetic field into a coefficient estimator;
calculating, by the coefficient estimator, new hard iron and soft iron coefficients upon receiving the measurements of the magnetic field;
determining a quality of the newly calculated hard iron and soft iron calculated coefficients; and
updating existing hard iron and soft iron coefficients to the newly calculated hard iron and soft iron coefficients only if the quality of the newly calculated hard iron and soft iron coefficients is better than a quality of the existing hard iron and soft iron coefficients.
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Accused Products
Abstract
Apparatuses, methods and systems apparatus for automatically updating hard iron and soft iron coefficients of a magnetic sensor of a device are disclosed. One method includes making measurements of a magnetic field by the magnetic sensor during rotations of the device, determining by at least a criterion whether to input the measurements of the magnetic field into a coefficient estimator, calculating, by the coefficient estimator, new hard iron and soft iron coefficients upon receiving the measurements of the magnetic field, determining a quality of the newly calculated hard iron and soft iron calculated coefficients, and updating existing hard iron and soft iron coefficients to the newly calculated hard iron and soft iron coefficients only if the quality of the newly calculated hard iron and soft iron coefficients.
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Citations
20 Claims
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1. A method of automatically updating hard iron and soft iron coefficients of a magnetic sensor of a device, comprising:
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making measurements of a magnetic field by the magnetic sensor during rotations of the device; determining by at least a criterion whether to input the measurements of the magnetic field into a coefficient estimator; calculating, by the coefficient estimator, new hard iron and soft iron coefficients upon receiving the measurements of the magnetic field; determining a quality of the newly calculated hard iron and soft iron calculated coefficients; and updating existing hard iron and soft iron coefficients to the newly calculated hard iron and soft iron coefficients only if the quality of the newly calculated hard iron and soft iron coefficients is better than a quality of the existing hard iron and soft iron coefficients. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A sensing system that automatically updates hard iron and soft iron coefficients of a magnetic sensor of the system, comprising:
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the magnetic sensor operative to make measurements of a magnetic field during rotations of the device; electronic control circuitry, the electronic control circuitry operative to; determine by at least a criterion whether to input the measurements into a coefficient estimator to generate a new hard iron and soft iron coefficient calculation; calculate a quality of the new hard iron and soft iron coefficients; update existing hard iron and soft iron coefficients to the newly calculated hard iron and soft iron coefficients only if the quality of the newly calculated hard iron and soft iron coefficients is better than a quality of the existing hard iron and soft iron coefficients. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method of automatically updating coefficients of a magnetic sensor input to a Kalman filter of a device, comprising:
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sensing, by a magnetic sensor, a magnetic vector of an ambient magnetic field; tracking motion of the magnetic vector, wherein a tip of the magnetic vector traces to a surface of an ellipsoid; detecting whether the tip is tracing a new surface area of the ellipsoid, wherein a new surface area has not been previously traced; detecting whether the tip trace moves more than a predetermined minimum angular rotation; recording a certain number of magnetic measurements while the tip is tracing the new surface area and moving more than the a predetermined minimum angular rotation; for each new magnetic measurement; a. comparing angular rotation between successive new measurements and an angular rotation of a gyroscope measurement, and comparing angular rotation between successive prior measurements and angular rotation of the gyroscope measurement, and determine if the new magnetic measurements more closely match the gyroscope measurement; b. comparing a difference of a magnetic magnitude of successive measurements using newly calculated hard iron and soft iron coefficients, with a difference of magnetic magnitude of successive measurements using the previously calculated hard iron and soft iron coefficients, and determining if a magnitude difference for the newly calculated hard iron and soft iron coefficients is less than a magnitude difference for the previous calculated hard iron and soft iron coefficients; updating magnetic coefficients of the Kalman filter with the newly calculated hard iron and soft iron coefficients if the difference based on the newly calculated hard iron and soft iron coefficients more closely match, and differ by less.
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20. A method of tracking a magnetic field, comprising:
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measuring, by a magnetic sensor, successive magnetic vectors of a magnetic field; comparing an angular rotation between successive new measurements and angular rotation of gyro measurement, and comparing angular rotation between successive prior measurements and angular rotation of gyro measurement, and determining if the new measurements more closely match the gyro measurement; comparing a difference of magnetic magnitude of successive measurements using newly calculated hard iron and soft iron coefficients, with a difference of magnetic magnitude of successive measurements using previously calculated hard iron and soft iron coefficients, and determining if a magnitude difference for the newly calculated hard iron and soft iron coefficients is less than a magnitude difference for the previously calculated hard iron and soft iron coefficients; and updating magnetic coefficients of an adaptive filter with new coefficients if a difference based on the newly calculated hard iron and soft iron coefficients more closely match, and differ by less.
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Specification