Azimuth measuring device
First Claim
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1. An azimuth measuring device comprising:
- triaxial earth magnetism detecting means for detecting earth magnetism;
output data obtaining means for repeatedly obtaining triaxial output data not smaller than a predetermined number of times, the triaxial output data being obtained from the earth magnetism detecting means at a time when the direction of the earth magnetism detecting means changes in a three dimensional space;
reference point estimating means for estimating, using a statistical method, coordinates of a position where variation of distances from a group of triaxial output data obtained by the output data obtaining means is minimum in a three dimensional space in which the triaxial output data are placed by relating the values of the triaxial output data to the direction components of the respective axes, and for setting the coordinates which are estimated to as a reference point;
offset information calculating means for calculating offset information of output data from the earth magnetism detecting means based on coordinates of the reference point obtained by the reference point estimating means; and
plane determining means for determining whether a group of output data obtained by the output data obtaining means are distributed in the vicinity of a specific plane,wherein when it is determined by the plane determining means that the group of output data are distributed in the vicinity of the specific plane, the coordinates of the reference point are not estimated by the reference point estimating means, or the coordinates of the reference point estimated by the reference point estimating means are deleted.
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Abstract
An azimuth measuring device is provided that can obtain offset information when the direction of the azimuth measuring device is arbitrarily changed. The offset information is calculated based on coordinates of a reference point obtained by a reference point estimating system. The azimuth measuring device can obtain the offset information without obtaining erroneous offset information when changing direction.
22 Citations
15 Claims
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1. An azimuth measuring device comprising:
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triaxial earth magnetism detecting means for detecting earth magnetism; output data obtaining means for repeatedly obtaining triaxial output data not smaller than a predetermined number of times, the triaxial output data being obtained from the earth magnetism detecting means at a time when the direction of the earth magnetism detecting means changes in a three dimensional space; reference point estimating means for estimating, using a statistical method, coordinates of a position where variation of distances from a group of triaxial output data obtained by the output data obtaining means is minimum in a three dimensional space in which the triaxial output data are placed by relating the values of the triaxial output data to the direction components of the respective axes, and for setting the coordinates which are estimated to as a reference point; offset information calculating means for calculating offset information of output data from the earth magnetism detecting means based on coordinates of the reference point obtained by the reference point estimating means; and plane determining means for determining whether a group of output data obtained by the output data obtaining means are distributed in the vicinity of a specific plane, wherein when it is determined by the plane determining means that the group of output data are distributed in the vicinity of the specific plane, the coordinates of the reference point are not estimated by the reference point estimating means, or the coordinates of the reference point estimated by the reference point estimating means are deleted. - View Dependent Claims (2, 3, 4, 5)
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6. An azimuth measuring device comprising:
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triaxial earth magnetism detecting means for detecting earth magnetism; output data obtaining means for repeatedly obtaining triaxial output data not smaller than a predetermined number of times, the triaxial output data being obtained from the earth magnetism detecting means at a time when the direction of the earth magnetism detecting means changes in a three dimensional space; reference point estimating means for estimating, using a statistical method, coordinates of a position where variation of distances from a group of triaxial output data obtained by the output data obtaining means is minimum in a three dimensional space in which the triaxial output data are placed by relating the values of the triaxial output data to the direction components of the respective axes, and for setting the coordinates which are estimated to as a reference point; offset information calculating means for calculating offset information of output data from the earth magnetism detecting means based on coordinates of the reference point obtained by the reference point estimating means; plane determining means for determining whether a group of triaxial output data obtained by the output data obtaining means are distributed in the vicinity of a specific plane; plane estimating means for estimating the specific plane using a group of output data obtained by the output data obtaining means, and for setting the specific plane which is estimated as a reference plane; temporary reference point estimating means for estimating, using a statistical method, coordinates of a position where variation of distances is minimum on the reference plane obtained by the plane estimating means, the distances being those from a group of projected points where a group of triaxial output data obtained by the output data obtaining means are projected on the reference plane, and for setting the coordinates which is estimated as a temporary reference point; and reference point correcting means for correcting a temporary reference point obtained by the temporary reference point estimating means, and for setting the temporary reference point which is corrected as a reference point, wherein when it is determined by the plane determining means that the group of output data are distributed in the vicinity of the specific plane, the reference plane is estimated by the plane determining means;
a temporary reference point is estimated by the temporary reference point estimating means;
a reference point is calculated by the reference point correcting means; and
the offset information calculating means calculates offset information of output data of the earth magnetism detecting means based on coordinates of a reference point calculated by the reference point correcting means. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. An azimuth measuring device comprising:
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triaxial earth magnetism detecting means for detecting earth magnetism; output data obtaining means for repeatedly obtaining triaxial output data not smaller than a predetermined number of times, the triaxial output data being obtained from the earth magnetism detecting means at a time when the direction of the earth magnetism detecting means changes in a three dimensional space; plane estimating means for estimating a plane of which a group of triaxial output data obtained by the output data obtaining means locate in the vicinity, in a three dimensional space in which the triaxial output data are placed by relating the values of the triaxial output data to the direction components of the respective axes, and for setting the plane which is estimated as a reference plane; temporary reference point estimating means for estimating, using a statistical method, coordinates of a position where variation of distances is minimum on the reference plane obtained by the plane estimating means, the distances being those from a group of projected points where a group of triaxial output data obtained by the output data obtaining means are projected on the reference plane, and for setting the coordinates which is estimated as a temporary reference point; reference point correcting means for correcting a temporary reference point obtained by the temporary reference point estimating means, and for setting the temporary reference point which is corrected as a reference point; and offset information calculating means for calculating offset information of output data from the earth magnetism detecting means based on coordinates of the reference point obtained by the reference point correcting means. - View Dependent Claims (14, 15)
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Specification