Unmanned Aerial Vehicle (UAV)-Based Precision AS-Built Surveying for Institutional Buildings

This study utilizes UAV-based photogrammetry to perform a high-precision 3D as-built survey of newly constructed laboratory buildings at Bells University of Technology. The approach integrates GPS-enabled UAV data acquisition with advanced photogrammetric processing using Agisoft Metashape Professional, AutoCAD Carlson 2021, and Agisoft Viewer to produce high-resolution orthophotos and accurate 3D spatial models. Comparative analysis between orthophoto-derived measurements and architectural design specifications indicates dimensional deviations predominantly within ±5 mm across most building elements, confirming construction accuracy. However, the roofing components exhibit deviations of 90 mm in length and 100 mm in width, exceeding international tolerance thresholds, thereby indicating non-conformance that may impact structural performance and envelope integrity. Positional accuracy was further validated through geospatial overlay on Google Earth. The findings demonstrate the technical reliability of UAV-based as-built surveys for construction validation, offering a robust tool for quality assurance, regulatory compliance, and facility management in institutional infrastructure development.