Larson Design Group (LDG) provided an aerial survey using an unmanned aerial system (UAS) and terrestrial LiDAR services to a confidential client for the quality assessment and update of the existing AutoCAD documents as well as the development of additional detail related to the vertical structures the client’s facility located in Lehigh County, Pennsylvania.

The project involved developing a flight plan for the UAS utilizing the existing AutoCAD files, 3DR-Site Scan and the B4UFly application to assess the constraints associated with the Lehigh Valley facility location. Given the proximity to the Lehigh Valley International Airport, the project site was located within Class C airspace, requiring LDG to obtain permission from the FAA to operate the UAS within the controlled airspace. A ground control plan was developed to identify the locations of ground control points required to provide survey accuracies of 2 cm horizontal and 5 cm vertical. LDG also developed a plan to complete the terrestrial LiDAR scans required to fully document the exterior of structures that were not obtained during the aerial survey.

The aerial survey and terrestrial LiDAR data was combined creating a single, geospatially correct aerial mosaic of the facility and the associated grounds in an Autodesk compatible format. The aerial mosaic and 3D Point Clouds were aligned with the AutoCAD drawings provided by the client and a comparative analysis of the existing and new dataset was completed, with deviation identified via “redlines” and “annotations.” The record drawing updates were completed in accordance with the client’s CAD standards.