Patent ID: 6962001

Claim:
A magnetic north detecting device comprising: a 3-dimensional geomagnetism sensor unit including three geomagnetism sensors for detecting respective components of a geomagnetism magnetic field intensity in respective directions of three coordinate axes perpendicular to each other; and a 3-dimensional operation functional section for carrying out an operation on the basis of the components of the geomagnetism magnetic field intensity detected by the geomagnetism sensors included in the 3-dimensional geomagnetism sensor unit, and calculating a magnetic north direction of the geomagnetism, wherein the 3-dimensional operation functional section carries out the operation and calculates the magnetic north direction of the geomagnetism, based on two assumptions that: (i) at least one axis of three coordinate axes of the 3-dimensional geomagnetism sensor unit is level to the earth surface; and (ii) an angle of a geomagnetism magnetic field vector which is calculated from the components of the geomagnetism magnetic field intensity in respective directions of the three coordinate axes of the 3-dimensional geomagnetism sensor unit, referring to the earth surface, coincides with a dip angle of the geomagnetism which is assumed beforehand.