Regional GNSS Common Mode Error Correction to Refine the Global Reference Frame

Common mode error (CME) arises from various sources, including unknown regional errors, potential geophysical signals, and other factors present in global navigation satellite system (GNSS) coordinate solutions, undeniably affecting the GNSS precision. This research concentrates on the effects of CME correction in global IGS-based reference frame refinement. We first estimated the regional CME with principal component analysis to obtain CME-corrected GNSS coordinate solutions. Subsequently, effects on the global reference frame with the regional CME correction were analyzed in three aspects: accuracy improvement of the coordinate solutions, variation in the velocity field, and accuracy improvement of the Helmert parameters in the reference frame transformation. The results show that after applying CME correction, the GNSS coordinate accuracy was improved by 28.9%, 22.1%, and 29.5% for the east, north, and vertical components, respectively. Regarding the site velocities, the maximum difference in velocity reached 0.48 mm/yr. In addition, the standard deviation of the Helmert transformation parameters between the International Terrestrial Reference Frame (ITRF) and the IGS-based reference frame—exclusively derived from GNSS technology—was reduced by over 30%, indicating CME correction enhanced the accuracy of the transformation parameters and refined the IGS-based reference frame.