| 摘要 |
PURPOSE:To calculate an exact running distance of a vehicle, irrespective of a state of the road surface, by detecting a disturbance of a pulse period from a pulse generating means, and estimating an error of the running distance. CONSTITUTION:A pulse from a pulse generating means 12 in case a vehicle is running on a gravel road, an uneven road, a frozen road, etc. becomes a pulse having no regularity. In this case, a disturbance of a pulse period is detected 14, outputted to a distance error estimating means 15, and by this information, whether an error of a running distance is large or small, and a range of the error are estimated 15. Subsequently, a present position calculating means 16 calculates 16 the present position of the vehicle by an advance direction of the vehicle from a direction detecting means 11, the number of pulses from a pulse counter 13, and an error of the running distance estimated by the distance error estimating means 15 of the diameter of a wheel. Also, an on-map position determining means 17 determines a position on a map of the vehicle by information from the present position calculating means 16, and map information 18, in accordance with the error of the running distance, which has been estimated 15, and the map information is displayed 20 through a display control means 19. |
