About modernization of Ukrainian height system

Purpose. The purpose of this work is obtaining connections between the Baltic and European height systems based on the I class leveling between the Ukrainian and Polish control points of the base vertical networks and construction of the quasigeoid surface on the border area. Method. Full integration of the hight system of Ukraine into the European vertical reference system (EVRS) consists of two stages: modernization of the height network of Ukraine through its integration into the United European leveling network UELN; construction and use as a regional vertical date the model of high-precision quasigeoid, which will be consistent with the European geoid EGG2015. The analysis of methods of high-precision leveling in Ukraine and Poland, and also the analysis of methods of construction of quasigeoid models in these countries is performed. Results. For integrating the Ukrainian hight system into the UELN/EVRS2000 system, the Ukrainian side performed I class geometric leveling along two lines: Lviv - Shehyni - Przemysl and Kovel - Yagodyn - Chelm with total length of 196 km. The root mean square systematic error on both lines of leveling was s<0.01 mm/km. In turn, the mean square random error along the line Lviv - Shehyni - Przemysl is h=0.29 mm/km, and along the line Kovel - Yagodyn - Chelm is h=0.27 mm/km. For double control on the cross-border part, the Polish side performed high-precision leveling with a length of 33 km. The differences between the Ukrainian and Polish leveling in all sections are within the tolerance. The analysis of influence of geodynamic phenomena on control of high-precision leveling is carried out. GNSS-leveling was performed on all fundamental and ground benchmarks, as well as horizontal marks. These measurements were used to build a quasigeoid model for the border area of Ukraine. The MSE of the obtained quasigeoid model is about 2 cm, which corresponds to the accuracy of the input information. Scientific novelty and practical significance. The connection of the Ukrainian and European height systems will ensure Ukraine’s integration into the European economic system, participation in international research of global ecological and geodynamic processes, study of the Earth’s shape and gravitational field and mapping of Ukraine using navigational and remote-sensing satellite technologies. Calculation of a high-precision model of a quasigeoid on the Ukraine area in relation to the European height system, agreed with the European geoid EGG2015, will allow to obtain gravity-dependent heights using modern satellite technologies.