Observations from permanent GNSS stations are actively used for the research and monitoring of geodynamic processes. Today, with the use of modern scientific programs and IGS products, it is possible to determine GNSS station coordinates and velocities at the level of a few millimeters. However, the scientific community constantly faces the question of increasing the accuracy of coordinate definitions to obtain more reliable data in the study of geodynamic phenomena. One of the main sources of errors is systematic measurement errors. To date, the procedure for their removal is still incomplete and imperfect. Also, during the processing of long-term GNSS measurements, it was found that the coordinate time series, after the removal of trend effects, are also characterized by seasonal variations, mainly of annual and semi-annual periods. We estimated the daily coordinate time series of 10 permanent GNSS stations in the central-eastern part of Europe from 2001 to 2019 and calculated the seasonal variation coefficients for these stations. The average value of the coefficients for the annual cycle for the N, E, and H components is −0.7, −0.2, and −0.7 mm, and for the semi-annual cycle the average value is 0.3, 0.4, and −0.5 mm. The obtained coefficients are less than 1 mm, which is why it can be argued that there is no seasonal component in the coordinate time series or that it is so small that it is a problematic task to calculate it. This practical absence of a seasonal component in long-term time series of GNSS coordinates, in our opinion, is partly compensated by the use of modern models of mapping functions (such as VMF3) for zenith tropospheric delays instead of the empirical GMF. To test the obtained results, we calculated the coefficients of seasonal variations for the sub-network of GNSS stations included in the category of the best EPN stations—C0 and C1. The values of the coefficients for the stations of this network are also less than 1 mm, which confirms the previous statement about the absence of a seasonal component in the long-term time series of coordinates. We also checked the presence of seasonal changes in the time series using the well-known decomposition procedure, which showed that the seasonal component is not observed because the content does not exceed 10% for additive decomposition and 20% for multiplicative decomposition.

The main goal of our research was to identify the features of the spatial distribution of crustal movements in Ukraine using GNSS-technology. Methods. As the initial date for investigation were the observations of 4 years (2013-2016) from over 120 reference stations in Ukraine. The cumulative solution was estimated by program GAMIT/GLOBK. For reference (real), we have taken solutions from EPN Analysis Combination Centre. By comparing the real coordinate and coordinate determined in our cumulative solution we compute RMS of the positioning. Results. The RMS analysis revealed that the received cumulative solution may be used for regional and local geodynamic studies, geophysical interpretation and for many practical applications in geodesy. Based on the estimated horizontal components of velocities, their vectors were constructed on the digital tectonic map of Ukraine. Horizontal rates (22-25 mm/yr) show a clear trenda dextral character. Movement components are in the direction of Voronezh crystalline massifs. For the vertical component of the relative site velocities, accuracy will increase with an increase in the time interval of GNSS-observations. Scientific novelty and practical significance. For the first time the digital tectonic map of Ukraine was prepared with vectors of horizontal velocities of GNSSstations. The values of the determined velocities are homogeneous and with the increase of the observation interval, it will be possible to determine the peculiarities of the movements of the earth crust on the territory of Ukraine and in the future to create a regional geodynamic model of Ukraine.

The emergence of satellite observations was marked by their widespread use to determine the velocities and direction of horizontal motions of lithosphere plates (modern kinematics of lithosphere plates), which allowed to research the deformation processes at the global and regional levels. Today, permanent GNSS stations cover a large part of the land area. Since many of these stations have accumulated a large amount of daily observation over 20 years, it is possible to trace the deformation processes of certain areas. There is the problem of correct identification of observations of the true parameters of the deformation process. This issue requires the joint work of geophysicists and geodesists. But high-precision time series and values of GNSS station velocities are important and perspective data for the interpretation of geodynamic processes, which are much easier to obtain than geophysical or geological data, do not require special costs and should take into account their active development, the number of such stations is growing rapidly. Today, according to unofficial data, more than 300 reference stations operate in Ukraine. The aim of this work is to detect deformations of the Earth's crust in the Carpathian folded system using GNSS technology. The input data for the research were the observations over eight years (2013-2020) at reference stations in Ukraine (ZAKPOS network). From these observations, the combined solution (coordinates time series and velocities) was calculated using the scientific software GAMIT / GLOBK. According to the obtained data, the horizontal displacements vectors of GNSS stations were also constructed, and the deformations of the Earth's crust were calculated by the method of triangles, the vertices of which are GNSS stations, using the GPS Triangle Strain Calculator software. The calculated values of deformations showed a different geodynamic value, depending on the location of the triangles. In particular, the active zones of stretching (Rakhiv-Verkhovyna and Syanok-Ustryky-Dolishni) and compression (Rakhiv-Khust-Mukachevo) were identified. The research results make it possible to establish the features of the spatial distribution of crustal movement in the Carpathian region and in the future in a joint interpretation with geophysical data to create a regional geodynamic model of the Carpathian folded system.