Unmanned Aerial Vehicle Surveying for Roads Construction and Maintenance

Abstract

This article studies the application of unmanned aerial vehicles (UAVs) for measuring earthwork volume by using the surface-to-surface method. It compares embankment volume between total station survey and UAV. The aerial photographs are controlled using Ground Control Points (GCPs), with a total of 5 points. The GCPs are measured using a Global Navigation Satellite System (GNSS) receiver in a Network Real-Time Kinematic (RTK) system. The study area is a local road in Lampang Province. The flying heights were 131 meters above the terrain with total of 35 images at average ground sampling distance (GSD) about 3.60 cm per pixel. Frontal and side overlap settings were at 85% and 75% respectively. The positional accuracy of the aerial photographs acquired by the UAV is compared to the check points, and the displacements in the X, Y, and Z axes are found to be 6.787 4.023 and 5.048 cm. respectively. The horizontal and vertical positional accuracies are evaluated against the ASPRS standards. The horizontal accuracy is within the class 12.5 cm, and the vertical accuracy is within the class 20 cm for vegetated areas. The earth volume calculation is performed using the Earthwork Reports method, employing the Surface-to-Surface calculation approach. The calculated earth volumes from the surveying camera and aerial photographs are determined to be 620.5 cu.m. and 570.7 cu.m. respectively, resulting in a difference of 49.8 cubic meters or approximately 8%. This study shows the application of unmanned aerial vehicles and GNSS-Based DEMs for evaluating earthwork volume which can be applied road construction and maintenance works.