Patent ID: 7305315

Claim:
A method of compensating tilt comprising: measuring geomagnetic field values of the X and Y axes tilted at a predetermined angle by using a two-axis geomagnetic sensor; measuring gravity acceleration values of the X, Y, and Z axes in the tilted state by using a three-axis acceleration sensor; judging that the X or Y axis of the two-axis geomagnetic sensor is perpendicular when the Z-axis gravity acceleration value and the X-axis or Y-axis gravity acceleration value are all substantially 0, and storing the geomagnetic field value measured in the X or Y axis of the two-axis geomagnetic sensor as a Z-axis geomagnetic field value; and calculating an azimuth angle by using the geomagnetic field values of three axes, the azimuth angle being compensated for azimuth errors caused by the tilt of the two-axis geomagnetic sensor.