| 摘要 |
PURPOSE:To prevent the wear and the deterioration of a medium drive device, and to calculate a vehicle position continuously for a long time by driving a medium by the medium drive device only when the medium drive device reads map information. CONSTITUTION:At the time of reading the digital map information from a CD-ROM medium 11, a position calculation device 14 outputs a CD-ROM start signal to a drive control part 15, and the drive control part 15 starts the revolving mechanism 12a and the pickup mechanism 12b of a CD-ROM drive device 12. When the read of the digital map information is completed, the position calculation device 14 stops outputting the CD-ROM start signal, and the drive control part 15 stops the revolving mechanism 12a and the pickup mechanism 21b of the CD-ROM drive device 12. Thus, by driving the medium 11 only when the medium drive device 12 reads the map information, the wear and the deterioration of the medium drive device is eliminated, and the vehicle position can be calculated continuously for a long time. |
