A vehicle navigation apparatus detects a current position and a travel direction of a vehicle, causes a display apparatus to display a vehicle mark corresponding to a detection result along with a road map, and thereby provides a driver with the vehicle travel guidance.
As described in patent literatures 1 and 2, a known vehicle navigation apparatus includes a gyro sensor and detects a vehicle position and a travel direction according to known dead-reckoning navigation based on an angular velocity detected by the gyro sensor and a detection signal from a vehicle speed sensor or an acceleration sensor (vehicle speed or acceleration).
Characteristics of an angular velocity detected by the gyro sensor vary with an ambient environment such as temperature.
For this reason, a vehicle navigation apparatus including a gyro sensor generally performs zero point correction, namely, setting a zero point for gyro sensor output when the vehicle navigation apparatus starts up by powered on or the traveling vehicle stops (e.g., see patent literature 3).
A reason for performing the zero point correction at a time of startup of the vehicle navigation apparatus or a time of a stop state of the vehicle is that no angular velocity is applied to the gyro sensor (i.e., angular velocity=0) in this case.