Patent ID: 7278219

Claim:
A magnetic compass comprising: a three-axis magnetic sensor for detecting geomagnetic vector as geomagnetic components of three orthogonal axes x, y, and z; data-plane calculating means for calculating a data plane on which output data of the three-axis magnetic sensor are present in a sensor coordinate system of the three axes x, y, and z by using geomagnetic vector data respectively detected by the three-axis magnetic sensor when the three-axis magnetic sensor changes its orientation to at least three different arbitrary directions within a horizontal plane; unit vector calculating means for calculating unit vectors of a horizontal coordinate system of three orthogonal axes X, Y, and Z whose Z-axis defines a vertical direction and whose X-Y plane defines a horizontal plane relative to the earth; horizontal coordinate system conversion means for converting the geomagnetic components in the sensor coordinate system detected by the three-axis magnetic sensor into geomagnetic components in the horizontal coordinate system; azimuth calculating means for calculating an azimuth on the basis of the converted geomagnetic components in the horizontal coordinate system; and display means for displaying the calculated azimuth.