## 5 Conclusions
This framework should go beyond simple seven-parameter Helmert transformations and incorporate region-specific parameters and deformation models to account for local crustal instabilities. Recent research by [36] demonstrated that ITRF2020 offers clear improvements in the observational precision of GNSS, SLR, VLBI, and DORIS inputs compared to ITRF2014, using Terrestrial Reference Frame (TRF) stacking methods. These results underscore the reliability of ITRF2020 as a reference frame for future coordinate transformations. Complementing this, ref. [34] analyzed the contribution of the International GNSS Service (IGS) to ITRF2020 and confirmed significant enhancements in frame consistency and coordinate integrity throughout the global GNSS network. This finding reinforces the compatibility between ITRF2020 and Korea's national GNSS infrastructure. Furthermore, static reference frames, such as KGD2002, are inherently limited in their ability to model long-term crustal motion and are particularly inadequate for capturing abrupt tectonic events like earthquakes. Consequently, discrepancies between the reference frame and actual ground positions can accumulate over time, a phenomenon known as datum deformation [36]. This issue is further exacerbated by the practice of datum holding, where a reference frame is maintained without periodic updates, despite ongoing geophysical changes [32]. These limitations underscore the necessity of transitioning toward semi-dynamic or fully dynamic reference frames to ensure long-term positional consistency. A semi-dynamic reference frame corrects for site motions using long-term average velocities, providing epoch-adjusted coordinates. In contrast, a dynamic reference frame incorporates time-dependent 4D positioning (3D + time), allowing real-time or epoch-specific representations of crustal displacements. These frameworks are increasingly critical in geodetic and geospatial applications that demand millimeter-level accuracy, particularly in tectonically active regions [37]. In summary, the transition to an ITRF2020-based dynamic reference frame represents more than a technical update--it serves as a foundational upgrade that will enhance positional accuracy, improve consistency with international services, and better support both scientific research and high-precision applications. Future efforts should focus on developing a regionally adapted 4D transformation model, conducting a national re-adjustment of control points, and reviewing any identified outlier stations (e.g., in Jeonnam province) to ensure a smooth and robust adoption of the new geodetic standard. Furthermore, practical implementation of a time-dependent reference frame should consider user accessibility. Providing user software with built-in epoch-aware coordinate updates or simple epoch conversion tools could ease the transition for field users and surveyors. In conclusion, this study not only quantifies the present internal consistency of GNSS solutions in Korea's national datum but also offers a clear direction toward future modernization. Embracing a dynamic geodetic datum, aligned with ITRF2020 and its principles,will enhance positional accuracy, ensure long-term consistency, and support both everyday surveying and advanced scientific research. These steps are essential to secure a future-proof geodetic foundation for the Republic of Korea. Conceptualization, S.-J.L. and H.-S.Y. ; methodology, S.-J.L. ; software, S.-J.L. ; validation, S.-J.L. and H.-S.Y. ; formal analysis, S.-J.L. ; investigation, S.-J.L. ; resources, S.-J.L. ; data curation, S.-J.L. ; writing--original draft preparation, S.-J.L. ; writing--review and editing, H.-S.Y. ; visualization, S.-J.L. ; supervision, H.-S.Y. ; project administration, H.-S.Y. ; funding acquisition, H.-S.Y. All authors have read and agreed to the published version of the manuscript. This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS-2021-NR059478). Not applicable.