Patent attributes
A navigation device is designed to calculate the present position thereof based on the output data of a GPS unit in association with an acceleration sensor and a magnetic sensor. When the absolute value of the acceleration detected by the acceleration sensor is above the prescribed threshold, the navigation device calculates the present position based on the previously detected values of the position and running speed stored in memory. When the absolute value of the acceleration is below the prescribed threshold, the navigation device detects the uniform motion applied thereto; hence, it calculates the present position based on the bearing detected by the magnetic sensor as well as the previously detected values of the position and running speed stored in the memory with high precision irrespective of the offset error of the acceleration sensor.
