Patent ID: 7222045

Claim:
A posture angle processing apparatus comprising: a magnetic sensor for detecting a magnetic vector; a gravitational acceleration sensor for detecting a gravitational acceleration vector; a position information acquisition device for obtaining an absolute location for a current point; a dip angle database device for storing a correlation of the absolute location and a geomagnetic dip angle at a corresponding point; and a dip angle estimation and determination device, for, based on the absolute location of the current point received from the position information acquisition device, reading a geomagnetic dip angle for the current point from the dip angle database device, for employing the magnetic vector detected by the magnetic sensor and the gravitational acceleration vector detected by the gravitational acceleration sensor to calculate an angle formed by a horizontal plane and the magnetic vector, for comparing the angle formed by the magnetic vector and the horizontal plane with the geomagnetic dip angle for the current point, and for, when an error between the angle and the geomagnetic dip angle is within a predetermined range, outputting a true signal indicating that the magnetic vector detected by the magnetic sensor is reliable as a geomagnetic vector, and in other cases, outputting a false signal indicating that the current magnetic vector is not reliable.