Bearing Calculator and Error Correction Method
First Claim
1. A bearing calculator havinga geomagnetic sensor for detecting earth-geomagnetism anda control unit for calculating a geographical bearing based on detection values of the geomagnetic sensor, whereinsaid control unit can execute a offset error correction processing for correcting offset error to said geomagnetic sensor due to a change of magnetic field in the bearing calculator and,when detection values of said geomagnetic sensor become abnormal state, performs said offset error correction processing if the abnormal state continues for a predetermined time, and does not perform the offset error correction processing if the abnormal state ends within a predetermined time.
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Accused Products
Abstract
A bearing calculator provided with a geomagnetic sensor for detecting earth-geomagnetism and a control unit for calculating a geographical bearing based on detection values of the geomagnetic sensor. The control unit can execute offset error correction processing for correcting the offset error to the geomagnetic sensor based on a change in the magnetic field inside the bearing calculator. When detection values of the geomagnetic sensor enter an abnormal state, it performs said offset error correction processing when the abnormal state continues for a predetermined time, while does not perform the offset error correction processing when the abnormal state ends within a predetermined time.
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Citations
12 Claims
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1. A bearing calculator having
a geomagnetic sensor for detecting earth-geomagnetism and a control unit for calculating a geographical bearing based on detection values of the geomagnetic sensor, wherein said control unit can execute a offset error correction processing for correcting offset error to said geomagnetic sensor due to a change of magnetic field in the bearing calculator and, when detection values of said geomagnetic sensor become abnormal state, performs said offset error correction processing if the abnormal state continues for a predetermined time, and does not perform the offset error correction processing if the abnormal state ends within a predetermined time.
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12. An error correction method in a bearing calculator provided with a geomagnetic sensor for detecting earth-geomagnetism and a control unit for calculating a geographical bearing based on detection values of said geomagnetic sensor, comprising
an offset error correction processing step of correcting an offset error to said geomagnetic sensor due to a change of magnetic field in the bearing calculator; -
an abnormal state detection step of detecting that detection values of said geomagnetic sensor become abnormal; and a judgment step of judging whether or not an abnormal state continues for a predetermined time when the abnormal state is detected at said abnormal state detection step, wherein offset error correction processing step is carried out when it is judged in said judgment step that said abnormal state continues for a predetermined time, while said offset error correction processing step is not carried out when it is judged that said abnormal state does not continue for said predetermined time.
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Specification