| 摘要 |
PROBLEM TO BE SOLVED: To facilitate accurate computing of a forward road grade by using a conventional navigation device in a road grade computing apparatus. SOLUTION: Present position and traveling direction of an automobile are detected by an automobile position detection means 4a so as to convert coordinates of the automobile position into those on a map stored in a map information memory means 4b, and determine the present position and the traveling direction of the automobile. On the other hand, taking the automobile position as a traffic origin, a plurality of virtual points are set at predetermined distance intervals forwardly along a traveling road for the automobile by a road grade computing means 4d, while an elevation in a region wherein each virtual point is present is set as that for each virtual point on the basis of elevation information of an elevation information memory means 4e. And, a gradient between the automobile position and each virtual point is computed, while a forward road grade relative to the automobile is computed by averaging the gradients. |
