Along with the development of the technological possibilities, the Global Positioning Satellite System (GNSS) is increasingly used in geodetic measurements. Using GNSS, measurements are performed in horizontal plane as well as for point elevation determination. The aim of the article is to demonstrate that the GNSS measurements’ static mode has a high accuracy. To achieve the aim the following objectives were set: 1) to perform global positioning measurements in Class I national leveling network, 2) to calculate the elevation above the sea level, 3) to evaluate the accuracy of performed GNSS measurements. The following research methods were used: static measurement method and analytical method for comparison of the obtained data.

The results of the determined ionization identifier TEC (Total Electron Content) for continuously operating reference Global Navigation Satellite Systems (GNSS) stations are analysed. On the one hand, the data reflect the state of the ionosphere during the observation; on the other hand, it is a substantial tool for accuracy improvement and reliable determination of coordinates of the observation place. It was decided to solve a problem of restoring the spatial position of the ionospheric state or its ionization field according to the regular definitions of the TEC identifier, i.e. VTEC (Vertical TEC). We have described one possible way of solving this problem, which is based on mathematical modelling by using degree polynomials and trigonometric Fourier series. Degree polynomials describe the trend of function, whereas the trigonometric Fourier series are used in order to better simulate the fluctuation. The method was tested for network of permanent stations ZAKPOS.

According to the fast development and distribution of GNSS technologies all over the world, the large numbers of reference GNSS stations have appeared in Ukraine. These stations are included in the state and several private networks. The permanent GNSS observations gathered within these networks are processed and analysed by the Centre of Lviv Polytechnic National University. A cumulative solution (coordinates expressed at the specified epoch and velocities of all stations) was estimated by using the GAMIT-GLOBK software. The authors made several numerous tests using certain configuration of fiducial stations which belong to the EPN A class to transfer ITRF08 frame into Ukraine area and choose the best strategy of alignment of the Ukrainian national GNSS network to the EPN. Three different solutions with cretin tolerance set for Ukrainian GNSS network were estimated and each time the different set of coordinates was obtained. The differences reached several millimetres. Also for verification, our solution was compared with EPN solution. Received coordinates and velocities could have a geophysical interpretation and provide very useful information for local geodesy tasks.

The national geodetic infrastructure of Ukraine has developed rapidly into Ukrainian Coordinate Reference System UCS – 2000, a fully GNSS compatible coordinate reference system, which is realised through networks of active GNSS stations. They provide data for post processing and streamed raw data for real-time network (RTN) solutions. The RTN raw data are currently being used by both Trimble (ZAKPOS Network), Leica Geosystems (System Solutions Network) and Topcon (TNT - TPI Network) to provide independent RTN solutions. This study is the first in the public domain to evaluate the performance of RTN services in Ukraine and it is intended to provide guideline information for geo-spatial practitioners. Based on collecting RTN data at five locations and using standard observing and processing methods, an accuracy of 25 mm ±10 mm with respect to 2D coordinates and 34 mm ±14 mm with respect to the heights was achieved. The three systems were shown to be generally comparable although some initialization problems were experienced. The result has revealed expected ~2-5 cm (95%) precision for the horizontal and vertical components; however, large horizontal and vertical biases were observed, which can be as high as 8 cm.

The conservation and renovation of biological diversity of territories are of vital importance in Ukraine. The concept of ecological networks has laid the foundation of these issues. In Ukraine, the law “On the ecological network” was adopted, and ecological networks were developed at the regional level. However, most developments do not fully take into account the location of reserved territories and places of concentration of valuable flora and fauna, and also often do not correspond to the principle of formation of a holistic system, which significantly reduces their environmental significance and the expediency of practical implementation. The authors of the article consider that one should estimate the natural potential of the territories in detail and objectively, as well as provide recommendations for practical actions for the renovation of biological and landscape diversity. One can do it in the process of the development of local ecological networks (at the level of separate administrative regions and territorial communities). One has developed the structure of the ecological network on the example of Stryi district of Lviv region and determined the estimation of the spatial connectivity of its crucial elements. The problem is that most of the connecting territories are formed from semi-natural and unnatural lands (hayfields, pastures, arable lands), which complicates the practical side of the project implementation. One needs to develop an effective mechanism to encourage landowners and land users to carry out environmental activities; to increase investments in re-naturalization of lands; to conduct environmental education and environmental public awareness campaign; to provide local government and other stakeholders with consulting services for the development of ecological network development programs at the local level in Ukraine.

Local geodetic network is very important in harmonic development of city territory. On the base of the local geodetic network, cadastral and topographic surveying works, engineering geodetic works and executive measurements of newly built buildings and engineering networks are carried out. In the territory of Riga, the local geodetic network was started to create in 1880, and in the course of time, as the city expanded, necessity to have wider reference network emerged. In 2005, in the territory of Latvia, network of continuously working base stations LatPos was launched, which ensured completely new trends in execution of measurements and accuracy reached. One year later, base station network EUPOS-RIGA was launched in the territory of Riga. It can be regarded as consistent part of Riga local geodetic network. The purpose of the research was to state, what are differences between historically used coordinates of points of the local geodetic network, and coordinates that are determined by use of real time corrections of LatPos and EUPOS-RIGA base station network. Measurements were made in the territory of Riga in period from December 2016 until April 2017. In the framework of the research, 61 point of the local geodetic network was inspected and in 38 cases GNSS observations in RTK mode were completed. In the research, catalogues of coordinates of polygonometry points of sixties and eighties were used in order to compare what differences of coordinates existed historically. The main conclusion drawn during the research – historical points of the local geodetic network shall not be used for surveying works of any kind before improvement of them and before they comply with requirements of normative acts.

In order to evaluate the accuracy of the local geodetic network of Jurmala City, in research, comparison of fortyseven selected polygonometry network point coordinates with the obtained data was made by performing measurements by real time cinematic (RTK) method in LatPos base station system. Points were chosen so in order to cover evenly the entire territory of the city. At present, gradual renewal and improvement of the local geodetic network takes place in Jurmala. In Jurmala City, obtaining of data by GNNS data receivers is encumbered by large density of trees. Therefore the local geodetic network in city has very important role in order to ensure performance of geodetic measurements of high quality in the territory of the city. Aim of the research is to evaluate the accuracy of the local geodetic network of Jurmala City. The following tasks have been set for achieving the aim: research of the given problem, visit of the local geodetic network points, performing control measurements, data processing and analysis.