| 摘要 |
PROBLEM TO BE SOLVED: To accurately calculate a road grade at a specific spot ahead of a self vehicle while suppressing an influence by a measuring error of an altitude.SOLUTION: A navigation device 1 stores map data including altitude information of respective spots preset on a road in an HDD 13, and causes a control unit 10 to execute processing for detecting a self vehicle location. The navigation device sets a road grade calculation object spot on the basis of the self vehicle location detected by road grade calculation processing executed by the control unit 10, identifies two acquisition object spots that are forward and rearward separated from the calculation object spot by a prescribed separation distance D respectively, and acquires altitude information corresponding to the two spots from the map data. The road grade at the calculation object spot is calculated based on the altitude information acquired in such a manner. |
