Effect of Temporary Local CORS Configuration Shifts on GNSS Base–Rover Positioning in Idu, Abuja, Nigeria

Temporary changes to Continuously Operating Reference Station (CORS) configuration parameters can compromise the accuracy of high-precision Global Navigation Satellite System (GNSS) positioning. This study assessed the effects of temporary local CORS configuration shifts on conventional Base–Rover GNSS positioning using AUSPOS-derived static coordinates as the reference standard. Eighteen established geodetic control stations (B03101 and GU1–GU17) within the Idu CORS coverage in Abuja, Nigeria, were observed using dual-frequency geodetic GNSS receivers. Three datasets were analyzed: conventional Base–Rover observations under the normal CORS configuration, CORS observations after a temporary configuration shift, and static GNSS observations processed with AUSPOS. Coordinate residuals, Horizontal Position Error (HPE), Three-Dimensional Position Error (3DPE), Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Standard Deviation (SD) were computed relative to the AUSPOS reference, while paired sample t-tests and one-way ANOVA were performed at the 95% confidence level. The conventional Base–Rover solution achieved a horizontal RMSE of 0.071 m compared with 0.694 m for the shifted CORS solution, indicating substantial degradation in horizontal positioning. Vertical RMSE values were similar (0.387 m and 0.383 m), suggesting minimal impact on height. Significant differences were observed for northing, easting, HPE, and 3DPE (p < 0.001), whereas height was not significantly affected (p = 0.860). ANOVA further confirmed significant differences in overall positioning accuracy (F = 168.42, p < 0.001). The findings demonstrate that temporary CORS configuration shifts introduce systematic horizontal biases into rover solutions, highlighting the need for independent validation of CORS coordinates using rigorous static GNSS processing, such as AUSPOS, following maintenance or configuration updates.