Enhancing Geodetic Control Points through GNSS and CORS Integration: A Case Study of Ibadan, Nigeria

Context and background: The second order geodetic control points in Ibadan are experiencing several challenges ranging from outdated infrastructure, positional inaccuracies and urbanization demands, which can be solved by enhancing the accuracies of these control points. The existing network of control points, which were established a long time ago, revealed several inconsistencies such as positional shift up to 1 meter and inaccessible or missing control points (6.8% of 2,101 points surveyed). Goal and objectives: This research aimed to enhance the accuracy and reliability of the control points by incorporating Global Navigation Satellite Systems (GNSS) and Continuously Operating Reference Stations (CORS). Methodology: Static GNSS observations with a minimum of 60 minutes observation session were conducted on 1,958 control points, the baseline distances ranges from 30 to 120 km. Data processing, encompassing least squares adjustments and data quality assessments, achieved residuals within ±2 mm and root mean square errors (RMSE) under ±20 mm for all axes, aligning with second-order geodetic standards. Results: The enhanced network improved positioning accuracy and consistency, agrees with international geodetic frameworks, and supports significant applications such as infrastructure development, environmental monitoring, and disaster management. This study demonstrates that integrating GNSS and CORS technologies notably improves the reliability of geodetic control networks, thereby ensuring their utility for sustainable urban development.