Exploring the accuracy of height measurements with multi-constellation RTK GNSS

Accurate height determination is crucial in various geospatial applications, and Real-Time Kinematic (RTK) GNSS plays a key role in providing high-precision positioning. This study explores the accuracy of multi-constellation RTK GNSS height measurements by comparing them with ground truth static data collected over different observation periods (2-hour, 1-hour, and 30-minute sessions). Three RTK configurations: GPS-only, GPS + GLONASS + Galileo, and a full GNSS solution (GPS + GLONASS + Galileo + BeiDou), were assessed to determine their relative performance in height estimation. The results indicate that longer observation durations improve accuracy, with the 2-hr session yielding the smallest errors across all configurations. Multi-constellation solutions generally outperformed GPS-only configurations, providing more stable height measurements, although the GNSS RTK configuration exhibited the largest variations in the 30-minute session. A one-way ANOVA analysis at a 95% confidence level confirmed that the variations between different RTK configurations were statistically insignificant, implying that all solutions exhibit similar uncertainties. These findings emphasize the benefits of integrating multiple satellite constellations for RTK positioning while also highlighting the importance of observation duration and site-specific factors in height determination.