Heading detecting apparatus
First Claim
1. A heading detecting apparatus attached to a moving object and including a geomagnetic field sensor for detecting the direction of the earth'"'"'s magnetic field in terms of two orthogonal components and a computing circuit responsive to orthogonal first and second electric signals from said geomagnetic field sensor to compute a heading of said moving object and generate a heading signal, wherein said computing circuit comprises:
- means whereby when one of first and second output values (X'"'"', Y'"'"') respectively proportional to said orthogonal first and second electric signals (X, Y) attains a predetermined value, one of first and second offset values (X offset, Y offset) for the other of said first and second output values is repeatedly computed and stored; and
means for repeatedly during operation of said apparatus correcting said electric signals from said geomagnetic field sensor in accordance with said offset values to derive said first and second output values for computing the heading signal of said moving object therefrom.
1 Assignment
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Accused Products
Abstract
A heading detecting apparatus is attached to a moving object and includes a geomagnetic field sensor for detecting the direction of the earth'"'"'s magnetic field in terms of orthogonal first and second signals and a computing circuit responsive to orthogonal first and second electric signals from the geomagnetic field sensor. In the computing circuit, when any one of the orthogonal first and second electric signals from the geomagnetic field sensor is a predetermined value, the value of the other electric signal is detected so that in accordance with the detected value an offset value is computed and stored, and the electric signals from the geomagnetic field sensor is corrected in accordance with the offset values.
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Citations
9 Claims
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1. A heading detecting apparatus attached to a moving object and including a geomagnetic field sensor for detecting the direction of the earth'"'"'s magnetic field in terms of two orthogonal components and a computing circuit responsive to orthogonal first and second electric signals from said geomagnetic field sensor to compute a heading of said moving object and generate a heading signal, wherein said computing circuit comprises:
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means whereby when one of first and second output values (X'"'"', Y'"'"') respectively proportional to said orthogonal first and second electric signals (X, Y) attains a predetermined value, one of first and second offset values (X offset, Y offset) for the other of said first and second output values is repeatedly computed and stored; and means for repeatedly during operation of said apparatus correcting said electric signals from said geomagnetic field sensor in accordance with said offset values to derive said first and second output values for computing the heading signal of said moving object therefrom. - View Dependent Claims (2, 3, 4)
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5. In a heading detecting apparatus attached to a moving object and comprising a geomagnetic field sensor for detecting the direction of the earth'"'"'s magnetic field in terms of orthogonal first and second signals and a computing circuit responsive to orthogonal first and second electric signals from said geomagnetic field sensor to compute a heading of said moving object and generate a heading signal, the improvement wherein said computing circuit comprises:
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means for repeatedly during operation of said apparatus eliminating instantaneous abnormal values of first and second output values (X'"'"', Y'"'"') respectively proportional to said orthogonal first and second electric signals (X, Y) from said geomagnetic field sensor; means for repeatedly during operation of said apparatus computing and storing offset values (Xo, Yo) for said orthogonal first and second electric signals from said geomagnetic field sensor when said first and second values (X'"'"', Y'"'"') satisfy a predetermined condition after the elimination of the abnormal values thereof; and means for repeatedly during operation of said apparatus correcting said first and second electric signals (X, Y) from said geomagnetic field sensor having the abnormal values thereof eliminated in accordance with said first and second offset values (Xo, Yo) respectively to derive said first and second values for computing the heading signal of said moving object therefrom. - View Dependent Claims (6)
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7. In a heading detecting apparatus attached to a moveing object and comprising a geomagnetic field sensor for detecting the direction of the earth'"'"'s magnetic field in terms of orthogonal first and second signals and a computing circuit responsive to orthogonal first and second electric signals to compute a heading of said moving object and generate a heading signal, the improvement wherein said computing circuit comprises:
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means for repeatedly during operation of said apparatus computing and storing first and second offset values (Xo, Yo) of a circular vector locus of said orthogonal first and second electric signals (X, Y) from said geomagnetic field sensor in accordance with arbitrary three sets of first and second output values (X'"'"', Y'"'"') respectively proportional to said first and second electric signals; and means for repeatedly during operation of said apparatus correcting said orthogonal first and second electric signals (X, Y) from said geomagnetic field sensor in accordance with said offset values (Xo, Yo). - View Dependent Claims (8, 9)
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Specification