###### Abstract
Fourteen first-order continuously operating GPS stations (CORSs) were used to define the datum, and tens of thousands of second- and third-order control points were re-surveyed and integrated into the new frame. Notably, from 1997 to 2007, over 11,000 geodetic points across the Republic of Korea were observed with GPS to densify KGD2002. This hierarchical adjustment process--first fixing the origin and CORSs, then adjusting second-order, then third-order points--gradually shifted the national network from the old datum to KGD2002 with ITRF2000. The result was a unified, high-accuracy coordinate system underpinning all mapping and surveying activities in the country. KGD2002 significantly improved national geodetic consistency: it eliminated the old datum's distortions and ensured that coordinates are directly compatible with GPS-derived positions [12]. It is a static datum fixed at epoch 2002.0 (it does not account for ongoing crustal motion), which means coordinates remain reference-fixed to 2002--subsequent realizations (e.g., a 2010 update) were introduced to account for tectonic shifts. Overall, KGD2002's establishment was a foundational step for the Republic of Korea's geospatial infrastructure, enabling centimeter-level consistency nationwide and seamless integration with global coordinate systems. The aim of this study is to quantitatively compare coordinate solutions computed using GAMIT/GLOBK and Bernese software within the static KGD2002 reference frame (epoch 2002.0). Since 2008, in response to the increasing use of global navigation satellite systems (GNSSs), triangulation points--especially those located in remote and mountainous areas--have been systematically relocated to urban regions. This nationwide relocation and modernization initiative is referred to as the unified geodetic control point. Between 2008 and 2021, approximately 5500 unified geodetic control points (UGCPs) were established across the Republic of Korea. Traditionally, each UGCP was computed us ing observations from a set of four to five nearby satellite reference stations. However, due to inconsistencies in the selection of reference stations across regions, existing region-based adjustment strategies have proven insufficient in maintaining positional consistency on a national scale. To overcome this limitation, this study introduces a unified geodetic adjustment strategy that fixes 17 (strong constraints) consistent nationwide satellite reference stations as common control points [13; 14]. Within the KGD2002 reference frame, various GNSS data processing software can be used to compute station coordinates. Among them, two widely used scientific packages are GAMIT/GLOBK, developed at MIT, and Bernese, developed at the University of Bern. These two software packages employ different strategies for baseline processing, network adjustment, and reference frame alignment [15; 16; 17; 18; 19]. It is essential to evaluate how closely independently processed coordinate solutions align with the official reference frame. In this study, we perform a detailed comparison between GAMIT/GLOBK-derived coordinates and KGD2002, as well as between Bernese-derived coordinates and KGD2002. The comparison is based on 3164 unified geodetic control points (UGCPs) officially published in the KGD2002 frame, which are treated as truth references in the analysis.