Patent ID: 8577636

Claim:
A method of determining an azimuth in an electronic compass, wherein the electronic compass performs functions, the electronic compass includes a compass module and a control unit, the compass module including a magnetic sensor unit, the control unit includes an azimuth calculation program and a calibration program, the method comprising: using a control unit to perform an azimuth calculation utilizing output from the magnetic sensor unit, the magnetic sensor unit including magnetic sensor elements corresponding to at least three axes for magnetic detection, wherein the magnetic sensor unit outputs three dimensional output corresponding to X, Y, Z axes, wherein the azimuth calculation comprises: selecting three points selected from random outputs of the magnetic sensor, wherein the three points constitute three corners of a triangle in a three dimensional space; determining a circumcircle which passes through the three points, which are the three corners of the triangle; and performing the azimuth calculation using a center coordinate of the circumcircle and an output value of the magnetic sensor, wherein the azimuth calculation is performed by rotating an output value A (Ax, Ay, Az) through coordinate rotation about X axis, the center of the circumcircle is moved on the Z axis by the rotation, the rotation renders the output value A (Ax, Ay, Az) to A′ (A′x, A′y, A′z), wherein azimuth angle is obtained from the equation λ=tan−1 (A′y/A′x), wherein the azimuth calculation program determines the azimuth calculation using output of the magnetic sensor elements, and the calibration program determines a reference point of output of each magnetic sensor elements using output of the magnetic sensor unit.