Road Slope Estimation Algorithm and Safety Analysis of Mountainous Road

Abstract

Considering the three-dimension variation of the road surface, a new method to estimate road slope and turning radius of mountainous road is presented in this paper. In this method, the vehicle state equation, based on GPS expression in geographic Cartesian coordinate system, is presented directly. This avoids the approximation that Earth’s surface is assumed to be a plane. Then the road surface is described and fitted in subparagraph combined the measurement information from GPS and IMU. By going forward the road sections piecewise, the whole road surface can be obtained. Based on the obtained road surface, longitudinal road slope and turning radius can be estimated. This management reduces the effects of random and cumulative error during the measurement. What is more, this method can deal with the condition that when the GPS record is missing by splining interpolation for the established state equations. The effectiveness of this method is verified by the experiment on some mountainous road in Shaanxi Province. Finally, the critical velocity and critical acceleration for safety driving on mountainous road is discussed.