Comparing Bulk Volume Measurements between Surveying GPS and UAS-Mounted LIDAR

Accurate volume measurements of bulk construction materials are crucial to create reliable cost estimates and schedules for construction projects. The traditional method of bulk volume measurements uses surveying GPS to capture the coordinates of perimeter and surface points at appropriate locations of the bulk pile. These geographical points are then used to establish a triangulated irregular network of the bulk pile surface. While the surveying GPS method is a convenient approach to quickly estimate the bulk volume, its accuracy is questionable because the limited amount of perimeter and surface points captured on the pile is not able to precisely represent its actual geometry. In addition, this method requires a GPS operator to physically climb onto the bulk pile. This paper presents the workflow and findings of using the UAS-mounted LIDAR approach. A customized commercial UAS with a professional LIDAR sensor was used to capture the entire surface of a construction material pile at low altitudes, and the results from the LIDAR sensor were compared with volume measurements using the surveying GPS method. Using UAS-mounted LIDAR will not only significantly improve the work efficiency for construction bulk volume measurements but also provide highly accurate results compared with the traditional surveying GPS method.