Patent ID: 8898005
Filing Date: 2014-11-25
Classification: G01C

Abstract:
1. An on-board apparatus, comprising: a map data storage unit in which map data that include altitude information for predetermined geographical points on roads are stored; a subject vehicle position detection unit that detects a subject vehicle position; a calculation target geographical point setting unit that sets a calculation target geographical point based upon the subject vehicle position; an altitude information acquisition unit that obtains altitude information corresponding to two geographical points, one of which is present ahead of the calculation target geographical point and apart from the calculation target geographical point by a predetermined separating distance, the other of which is present behind the calculation target geographical point and apart from the calculation target geographical point by the separating distance, from the map data; a road grade calculation unit that calculates the road grade at the calculation target geographical point based upon the altitude information obtained by the altitude information acquisition unit; and a separating distance adjusting unit that adjusts the separating distance in correspondence to the calculation target geographical point, wherein: