Comparison of tutga data on a province-region-country basis using up-to-date and high-resolution geopotential models

In order to Express the Earth mathematically, the reference ellipsoid must be modeled. The surface of the geoid and the surface of the ellipsoid are separated from each other because of their shape. Some of the obtained physical values are key issues in solving our engineering problems. Geodetic corrugation value, orthometric heights and ellipsoidal height values allow to calculate the differences between these surfaces. Prior to satellite-based measurements, geoid corrugation was performed with techniques such as astrogeodetic observations and gravimetric measurement. Both of these techniques are preciseand long-lasting. Effective controls cannot be made for its results. With the development of satellite technology, ellipsoidal heights have become measurable in seconds. Although these measurements are highly controlled and accurate, they were made in a very short time and frequently. In this research, the models that will give the best results for our study areas from the current and high-resolution global geopotential models have been investigated. As the study area, Turkey was studied separately as Regions and Provinces. 36°N ≤ φ ≤ 42°N; It covers an area of approximately 769,632 km² with in the boundaries of 26° E≤ λ ≤ 45° E coordinates. 582 point GNSS/Leveling points belonging to Turkey National Basic GPS Network (TUTGA) used for testing Global Geopotential Models based on geoid height were used.Calculations of the differences between the geoid heights obtained from the global geopotential models and the geoid heights obtained from the GNSS/Leveling points were made using Excel. By examining the differences between the Orthometric and Ellipsoidal heights of the TUTGA points and the Global Geopotential Models, the best model selected as a result of the researches on the basis of Turkey, regions and provinces was examined in terms of square mean errors. , SGG-UGM-2 for Marmara Regions, XGM2019E-2159 for Eastern Anatolia, Southeast Anatolia, Mediterranean Regions, GECO model for Black Sea Region was deemed appropriate. As a result of the calculations made on the basis of provinces, the highest mean square error value (1.5903 m) was seen in the Geco Model for Ardahan province, and the lowest error value (0.4867 m) was seen in the EGM2008 model for Şırnak Province.