MAGNETIC FIELD DETECTOR

PROBLEM TO BE SOLVED: To enable correction of a reference origin by an operation when offset or a change in magnetic field intensity is brought about by an external magnetic field or the like, in a magnetic field detector using sensors of three axes, which detects magnetism such as terrestrial magnetism. SOLUTION: Based on detection outputs from three magnetic sensors, coordinate point data on a magnetic vector are determined as a point on spherical coordinates Ga of a radius Ra. At the time when coordinate point data Dx, Dy and Dz are separate greatly from the spherical coordinates Ga, a virtual origin I1 being separate by the radius Ra from both of the two coordinate point data Dx and Dy, and a virtual origin I2 being separate by the radius Ra from both of the two coordinate point data Dy and Dz, are found. Virtual origins I3 and I4 are found by lengthening the radius a little. A distance d1 between the virtual origins I1 and I2 and a distance d2 between the virtual origins I3 and I4 are compared and it is determined whether the radius Rb of new spherical coordinates Gb is longer or shorter than the original radius Ra. By repeating this, a new reference origin Ob is found. COPYRIGHT: (C)2011,JPO&INPIT