System and method for magnetic field data compression
First Claim
1. A method for calculating values based on magnetic field information from a magnetic sensor in a sensing unit containing the magnetic sensor and at least one other sensing modality capable of providing a direct or derivative measure of change in orientation, the method comprising:
- sampling a magnetic field via the magnetic sensor at a plurality of points in time at a sample rate;
sampling the at least one other sensing modality capable of providing a direct or derivative measure of change in orientation of the sensor unit at each of the plurality of points in time;
rotating to a common time instant one or more of the plurality of magnetic field samples collected within a time interval using the orientation of the sensing unit at each of the plurality of points in time, estimated by means of the other sensing modality, in order to eliminate variations between magnetic samples due to changes in orientation of the sensor unit within such time interval;
using the magnetic samples corrected for the sensor rotation in such interval to calculate magnetic field related information specific to the given time interval; and
communicating to a receiver the magnetic field related information at an average rate lower than the sample rate.
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Accused Products
Abstract
A technique for calculating magnetic field information from a magnetic sensor employs a sensing unit containing the magnetic sensor and another sensor capable of providing a measure of change in orientation. The method includes sampling a magnetic field at points in time and sampling the other sensor at each point in time. The method then entails rotating to a common time instant the magnetic field samples using the orientation of the sensing unit estimated by means of the other sensing modality in order to eliminate variations between magnetic samples due to changes in orientation of the sensor unit within such time interval. The magnetic samples, corrected for the sensor rotation in such interval, are used to calculate magnetic field related information specific to the given time interval and the magnetic field related information is communicated to a receiver at a rate lower than the sample rate.
18 Citations
12 Claims
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1. A method for calculating values based on magnetic field information from a magnetic sensor in a sensing unit containing the magnetic sensor and at least one other sensing modality capable of providing a direct or derivative measure of change in orientation, the method comprising:
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sampling a magnetic field via the magnetic sensor at a plurality of points in time at a sample rate; sampling the at least one other sensing modality capable of providing a direct or derivative measure of change in orientation of the sensor unit at each of the plurality of points in time; rotating to a common time instant one or more of the plurality of magnetic field samples collected within a time interval using the orientation of the sensing unit at each of the plurality of points in time, estimated by means of the other sensing modality, in order to eliminate variations between magnetic samples due to changes in orientation of the sensor unit within such time interval; using the magnetic samples corrected for the sensor rotation in such interval to calculate magnetic field related information specific to the given time interval; and communicating to a receiver the magnetic field related information at an average rate lower than the sample rate. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for calculating values based on magnetic field information from a magnetic sensor in a sensing unit containing the magnetic sensor and at least one other sensing modality capable of providing a direct or derivative measure of change in orientation, the method comprising:
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sampling a magnetic field via the magnetic sensor at a plurality of points in time at a sample rate; sampling the at least one other sensing modality capable of providing a direct or derivative measure of change in orientation of the sensor unit at each of the plurality of points in time; rotating to a common time instant one or more of the plurality of magnetic field samples collected within a time interval using the orientation of the sensing unit at each of the plurality of points in time, estimated by means of the other sensing modality, in order to eliminate variations between magnetic samples due to changes in orientation of the sensor unit within such time interval; providing a measure of the sensing unit velocity at each of the plurality of points in time; using the magnetic samples corrected for the sensor rotation in such interval and the sensing unit velocity at each of the plurality of points in time, to calculate magnetic field related information specific to the given time interval; and communicating to a receiver the magnetic field related information at an average rate lower than the sample rate. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification