Patent ID: 9164600
Filing Date: 2015-10-20
Classification: G01C,G01R,G06F

Abstract:
1. A mobile device comprising: a magnetic sensor; a posture detection sensor for detecting a posture of the mobile device independently of the magnetic sensor; a sampling data acquisition section for acquiring output data of the magnetic sensor as a plurality of sampling data items in a plurality of states in which the posture detection sensor determines that the mobile device is directed in directions different from one another, the plurality of sampling data items respectively corresponding to the plurality of states; an offset value calculation section for separately calculating a respective offset value for each of a plurality of orthogonal reference axes of the magnetic sensor, which are estimated to be output by the magnetic sensor when the magnetic sensor is not sensing geomagnetism based on the acquired plurality of sampling data items; and a storage unit for storing the respective offset values, wherein the offset value calculation section separately calculates a new offset value and evaluates a reliability of the new offset value, and updates a corresponding one of the offset values stored in the storage unit in accordance with the reliability of the new offset value such that: (i) when the reliability of the new offset value is high, the corresponding one of the offset values stored in the storage unit is replaced with the new offset value, and (ii) when the reliability of the new offset value is low, the corresponding one of the offset values stored in the storage unit is changed toward, but not replaced by, the new offset value.