Azimuth detecting device and azimuth detecting method

An azimuth detecting method, comprising the steps of:

• receiving an output value of a geomagnetic sensor;
• receiving, by a GPS signal receiver, a GPS signal that is used for measuring a position of a mobile object;
• calculating a gain correction amount, using a processor, by means of a method of least squares by using the output value of the geomagnetic sensor and correcting the output value of the geomagnetic sensor when a level of the GPS signal is lower than a predetermined value;
• and
• calculating a declination correction amount and/or an inclination correction amount by means of a method of least squares on the basis of information received from the GPS signal and correcting the output value of the geomagnetic sensor based on the calculated geomagnetic inclination correction amount and/or the calculated geomagnetic declination correction amount when the level of the GPS signal is at least the predetermined level.