Patent ID: 8112221

Claim:
A navigation apparatus for a vehicle, the apparatus storing map data in a hard disk drive having a magnetic disk and a magnetic head, reading from the hard disk drive map data relative to a proximity of a present position acquired by a present position detection device, and displaying the map data in a display device, the apparatus comprising: means for acquiring an atmospheric pressure of the present position using atmospheric pressure determination information or an atmospheric pressure sensor measuring an atmospheric pressure of the present position; means for acquiring a vibration amount generated by a travel of the vehicle; means for acquiring a marginal atmospheric pressure that corresponds to an atmospheric pressure amount which enables the magnetic head to maintain a lift from the magnetic disk when it is supposed that a vibration amount of the vehicle corresponds to the vibration amount acquired by the vibration amount acquiring means; and means for stopping a function needing an access to the hard disk drive when an atmospheric pressure measured by the atmospheric pressure acquiring means is less than the marginal atmospheric pressure acquired by the marginal atmospheric pressure acquiring means.