ASSESSMENT OF UAV AND GNSS IN ROUTE SURVEY TOWARDS VERTICAL ALIGNMENT DESIGN FROM OLURUNDA JUNCTION THROUGH BALOGUN VILLAGE TO OLURUNDA VILLAGE

ABSTRACT This project focuses on the assessment of the suitability of Unmanned Aerial Vehicle (UAV) and Global Navigation Satellite System (GNSS) techniques in route surveying towards alignment design between Balogun Village, via Ibrahim Chatta, to Olorunda Village, Oyo, Oyo State. The main objective was to evaluate the efficiency, accuracy, and practicality of combining UAV photogrammetry with GNSS ground observation for precise data acquisition and alignment modeling. The data acquisition was carried out using a DJI Enterprise Matrice 350 RTK drone and Unistrong G970ii Differential GNSS receiver operating in Real-Time Kinematic (RTK) mode. The UAV survey covered the entire 5.4 km route at a flight altitude of 60 meters with 70% forward and 60% side overlaps, while the GNSS observation provided accurate ground control and validation points collected at 25 meter intervals along the corridor. Both datasets were processed using PIX4DMAPPER and AutoCAD Civil 3D (2022) to produce orthomosaic images, digital terrain models, and alignment profiles suitable for engineering design purposes. The comparative analysis between the UAV derived and GNSS-observed data indicated a high level of consistency in elevation, planimetric accuracy, and route definition, demonstrating that UAV photogrammetry can effectively complement GNSS surveying in route alignment projects. The integration of both techniques reduced field time, improved data density, and enhanced visualization of the terrain. In conclusion, the study established that the combined application of UAV and GNSS technologies provides an efficient, cost-effective, and accurate approach to modern route surveying and alignment design. The methodology adopted in this project can serve as a reliable framework for future road design, topographic mapping, and civil infrastructure development projects.