Volume 113 (2022): Issue 1 (June 2022)

The paper studies the relationship between the ambient temperature change and the horizontal displacements on control points of the Dnieper Hydroelectric Station dam from 2016 to 2020. A specially developed software product analyzed the GNSS time series of measurements pre-processed by the GeoMoS system to determine the parameters of seasonal displacements and their relationship with seasonal changes in air temperature. The research established that the influence of ambient temperature in the absence of significant changes in the water level in the upper reservoir determines the cyclicity of dam deformations. It is established that the projections of velocity vectors of reference points in the ETRF-2014 system for the studied period do not exceed the absolute value of 3 mm/month. The directions of the horizontal displacement vectors in the first half of each year are opposite to the directions recorded in the second half. In the first half of the year, the dam’s body shifts towards the reservoir, while in the second half year period, it shifts-backwards. According to the three-year GNSS monitoring of the Dnieper Hydroelectric Station dam, the amplitude of semi-annual horizontal oscillations of the control points relative to the dam axis is from -9.5 to +8 mm. In winter and summer, the horizontal displacements increase from the edges of the dam to its central part, and the amplitudes of the horizontal displacements move vice versa. The obtained data establish a linear analytical relationship between the average temperature and the horizontal displacements of the GNSS control points.

Galileo is Europe’s Global Navigation Satellite System (GNSS), which provides improved positioning and timing data with significant benefits for many European services and users. Galileo enables users to know their exact location with greater precision than other available systems. Access to the Galileo signal in the obstructed and unobstructed environment provides benefits and opportunities for work, thanks to the improved performance and accuracy. The use of a Galileo-enabled receiver increases the number of satellites in view significantly. When compared to the performance of single-constellation receivers, this significantly reduces the time required to obtain a position with centimetre-level accuracy. The results indicate the current Galileo constellation’s suitability for high-precision RTK applications, as well as improved availability, accuracy, reliability, and time-to-fix in the obstructed and unobstructed environments. The results of RTK GPS and RTK GPS/Galileo obtained at different times of the same day by using two reference points were compared. The results of this study illustrate that integrating RTK GPS system with Galileo is favorable for surveying applications (cm accuracy). This study shows that in surveying applications requiring centimetre accuracy, the RTK GPS/Galileo method can replace other survey methods (Total Station).

Topographic, geodetic and cartographic activities are one of the main activities for the effective development of the economy, science of strengthening national security and defense. It is a set of management, production, scientific and educational activities for the storage and communication to users of geodetic and cartographic information and data. The article considers one of the segments of this activity – the state of geodetic support of the territory of Ukraine and its assessment according to official data on the possibility of creating topographic maps and plans of scale 1:25 000 – 1:2000 in compliance with applicable regulations. To carry out the assessment, around the points of the State Geodetic Network of Ukraine (DGM) buffer zones of radii of circles of standard sizes were constructed, zoning of the territory with Thissen-Voronoi polygons and covering of the territory in the form of a hexagonal grid were done by means of ArcGIS. The results of the current assessment as of 2022 conducted by three methods are summarized in the table in terms of oblasts of Ukraine. The data obtained are compared to the previous assessment conducted five years ago. Changes in the state of geodetic support have been identified and their objective reasons explained. The advantages and disadvantages of each of the proposed methods of geoinformation analysis of the assessment of the state of geodetic support of the territories are given. It is established that the combination of different methods will allow to use the existing points of DGM with greater efficiency and to substantiate the priority places for further development of the network. The complex of scientific and applied works related to the modernization of the state geodetic network will allow to quickly and locally develop a network based on satellite and computer technologies and create and present digital cartographic information at the modern scientific and technical level in accordance with current needs.