Slope Gradient and Vehicle Attitude Definition Based on Pitch and Roll Angle Measurements: A Simplified Approach
R. N. Barbosa1, *, J. B. Wilkerson2, H. P. Denton3, D. C. Yoder2
Identifiers and Pagination:Year: 2012
First Page: 36
Last Page: 40
Publisher Id: TOASJ-6-36
Article History:Received Date: 10/09/2009
Revision Received Date: 11/11/2010
Acceptance Date: 02/12/2011
Electronic publication date: 14/3/2012
Collection year: 2012
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Simplified models relating pitch and roll angle measurements of a roving vehicle to terrain slope and vehicle attitude were developed. The simplified models are based on previously published models by Rowe and Spencer  and Yang et al. . These simplified models are easier to implement using microcontroller technology reducing the number of trigonometric function calculations, improving program execution and simplicity. Simulated and field tests were conducted comparing published and simplified models. In a simulated test, agreement between models showed coefficient of correlation (r) results of 0.999 (p<0.05). Mean absolute deviation between models was less than 0.12° for slope gradient, and 0.51° for vehicle attitude. In a field test models were programmed in a microcontroller, a clinometer was used to obtain pitch and roll measurements of a roving ATV. Terrain slope results derived from pitch and roll measurements were compared to results derived from high accuracy GPS readings. Slope gradient results showed high coefficient of correlation, low absolute error and high model efficiency. Slope aspect results showed correct aspect classification more than 85% of the time.