A Comparative Study on Estimation of Unified Control Point Coordinates Using Multi-GNSS Baseline Vector Adjustments

This study focuses on assessing the estimation of UCP (Unified Control Point) coordinates using multi-GNSS baseline vector network adjustments. Campaign-based observations from 33 UCPs and two CORS (Continuously Operating Reference Stations) in Jeju region, Korea, were employed to generate 704 single baselines from eight constellation combinations of GPS, GLONASS, Galileo, and BeiDou. Both of minimally constrained and over-constrained adjustments were carried out to evaluate the impact of including multi-GNSS baseline vectors on network relative and absolute accuracy. The multi-GNSS solutions demonstrated enhanced accuracy compared with GPS-only results, with the vertical component showing a reduction of approximately 25 to 30% in the error bars. Statistical testing at the 95% confidence level further confirmed that coordinate differences between GPS-only and multi-GNSS adjustments were significant.