At the moment all three Baltic countries – Estonia, Latvia and Lithuania – use Baltic Normal Height System 1977 as a national height system. But the European Union regulations declared the European Vertical Reference System as a national height system. For height transformation there is a transformation formula for each European country. After calculations it is seen that height difference between Baltic Normal Height System 1977 and the European Vertical Reference System depends on point location in the territory (coordinates). This unequal height difference between both height systems will cause unequal height values on border connection points between the Baltic countries.

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 article presents the research study of the current state and condition of the geodetic base (polygonometric) network for Kaunas city and region as well as the aspects of its compiling. The geodetic base compiled in the post-war years is considered to be of high quality and is used nowadays. The still existing polygonometric network is seldom studied and thus it remains little known. For the purpose of defining the current state of the geodetic base networks, the search for the points in Karmėlava neighbourhood of Kaunas region has been provided. From the total number of 22 points to be searched, five (i.e. 22 percentage) were determined, but only four points (i.e.18 percentage) were appropriate for measurements. The majority of the points has been destroyed during the construction of the residential buildings or roads, or after the reconstruction works. The measurements have been taken by Trimble R6, by RTK method, 10 times for each point. The most reliable value of the measured geodetic points X and Y were defined as well as the errors of the mean square for one measurement and of the average. The results of the survey (100 respondents) showed that the majority of the professionals apply the points of the polygonometric network when making measurements. However, the problems related to a rather rear usage of the network and the aggravated search of the polygonometric points were encountered. A significant part of the professionals suggested the restoration of the polygonometric network.