Abstract: An offset correction apparatus comprising a turning angular velocity sensor, a vehicle speed sensor for outputting a pulsed signal every constant distance traveled by a vehicle, a stop determining unit for determining that the vehicle is at a stop, an offset calculation unit for integrating an output of the turning angular velocity sensor during a period of time that the stop of the vehicle is determined by the stop determining unit and then calculating an offset value of the output of the turning angular velocity sensor, a storage unit to store the offset value calculated by the offset calculation unit, and a heading correction unit for correcting heading data obtained from the output of the turning angular velocity sensor, with the offset value, wherein when the pulsed signal from the vehicle speed sensor disappears and the output from the turning angular velocity sensor is less than a threshold, the stop determining unit determines that the vehicle is at a stop.

Abstract: A heading detecting apparatus for estimating a current heading of a moving body is described that individually analyzes and evaluates error factors that are respectively included in the heading data of a magnetic sensor and in the angular velocity data of a turning angular velocity sensor (e.g., optical fiber gyro, mechanical gyro, vibration gyro, gas rate gyro) and determines the rate of use of the output data of the turning angular velocity and magnetic sensors.