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.

Cadastral measurements of land parcels are conducted under the guidance of territory planning documents designed by resolutions of the Government of the Republic of Lithuania which in turn regulate the collection of real property cadastral data. However, not always boundaries of the measured land parcels correspond to the documents of territory planning and factual consumption of land. This problem becomes obvious when measuring agricultural land which is most frequently formed in land management schemes during the land reform. The aim of the research is to analyze the correspondence of land parcels after cadastral measurements to the documents of territory planning, identifying discrepancies between line lengths and areas of land parcels. Having investigated the correspondence of agricultural parcels to territory planning documents on the basis of the line lengths designed, it was found that higher line lengths occurred after conducting cadastral measurements. Having identified discrepancies between the areas of agricultural parcels and territory planning documents, one can make an assumption that significant differences could be noticed which manifest inadequacy existing in territory planning documents.

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 purpose of the article is to present a combined approach that connects several methods and algorithms to increase the effectiveness of the geodetic network measurement structure for determining horizontal and vertical displacements of engineering objects. Determining the deformation of commercial objects and objects of practical value allows to assess their technical condition. In case of critical changes at such objects, appropriate planning of protection, reconstruction and modernization works is also provided and the negative impact of the environment and weather conditions is indicated. Regardless of the methods used, the measurement of movements and deformations of structures is always preceded by an analysis of the prevailing conditions, as well as a network of geodetic measurement determination and control. These analyses are carried out taking into account manufacturability, economy, and safe use of objects, human safety and environmental protection. The target function was defined, which in this case was chosen as the entropy of the geodesic observation network through the measurement of the parameters vector with true values. Analysing the structure of the control and measurement network and improving its efficiency by the number of necessary observations becomes important for determining reliable changes occurring at the object and the ability to conduct the necessary measurements in the shortest possible time. At the same time, the improved network structure should ensure the redundancy of observations made to match the geodetic network with the modified methods. The optimal number of observations in the geodetic network depended on the observation structure informativeness. During the research, it was noticed that the use of a combined approach will allow selecting only those observations that are the most informative. This will reduce the measurement time without reducing the accuracy of the received movements. The obtained results of the numerical analysis showed the performance of the offered solution for increasing the efficiency of the geodetic network structure formation. It also allows faster and more economical performance of engineering structures geodetic measurements.

This article is concerned with the problem of establishing process equipment deformation regularities, in particular, gas engine compressors at the compressor station of underground gas storage facility in Bohorodchany due to ground topographic surface vertical movements caused by gas flooding into and extraction from the reservoir bed in different seasons. Values of longitudinal and lateral pitches of gas-engine-compressor units’ foundation plates were determined using the results of topographic surface vertical movements monitoring. This provides an opportunity to predict adverse processes in gas engine compressors operation. On the other hand, this monitoring facilitates resolution of land resources sustainable and efficient use issues at underground gas storage territories.

The article generalizes theoretical and practical addition to the components of mathematical processing of geodetic measurements, which are the basis and used to support work in land management and cadastre. The research identifies general components of mathematical processing of geodetic measurements and components which are primarily used in the field of land management and cadastre. Completed investigation of the theoretical and practical foundations of these components and developed theoretical and practical additions improve the results of mathematical processing of geodetic measurements.

This article analyses the issue of the inadequacy between the results of preliminary measurements performed during the land reform and results of cadastral measurements. The aim of the research is to analyse the change of areas of land parcels of Sakiai district, the mistakes which were made during the measurements and their causes, as well as to make the comparison between preliminary and cadastral measurements. The research methods are as follows: the review and analysis of scientific literature, the analysis of statistical data, the comparative analysis and the method of graphical modelling. The total area of analysed land parcels is 282718 m2. During the research, while comparing the preliminary data and the data of the measurements of land parcels obtained while performing cadastral measurements, it was established that an average increase of areas of land parcels is 0.0223 ha, decrease is 0.0034 ha, the total perimeter of all land parcels decreased by 24.9 m, the total area of arable land in land parcels increased by 0.1390 ha due to the increase of areas of land parcels, new mapped lands: tree and shrub plantations, grasslands, gardens. The average shift of turning points of land parcel boundaries in the locality after the performed cadastral measurements is 2.64 m. What is more, by applying some formulae, the accuracy of calculation of areas of land parcels was determined. It turned out that land parcels, which cover 96% of the area of the analysed land parcels, changed to the maximum permissible error of areas, and 4% exceeded the maximum permissible error. According to the data presented by the National Land Service it was established that 15% of the submitted cadastral files are not accepted. The most common causes are an inadequacy of land parcel boundaries to the documents of the planning of territories or the land holding projects (44%), mistakes in the preparation of files of cadastral data of land parcel, in the completing (23%), in the preparation of the land parcel plan (21%), and while filling in the form of land parcel cadastral data (13%).

Some tasks require identification of landmarks in districts beyond the reach of existing optical observation facilities. The accuracy of their determination significantly affects the effectiveness of the use necessary equipment during the task. In the paper an algorithm to determine the object parameters using a flying platform is offered. An observation point is installed which is equipped with a navigation system to solve this task. This ensures its orientation and positioning. From the observation point an aerial observation point is displayed. It is suggested to use a flying platform. The coordinates of the flying platform are determined relative to the observation point; the coordinates of the landmarks are determined relative to the flying platform. The mathematical model of the estimation error determination of object coordinates with the help of a flying platform is proposed. The analysis of errors in determining the parameters of the object using a flying platform is conducted. Analysis of the results of mathematical modelling is conducted using the package of applications Mathcad. The dependence of these parameters on the relative position of the observation point, platforms and object is examined. It is shown that the main contribution to the error of determining the coordinates of the landmark is given by the errors of determining the observation point location and measuring the range. An analytical correlation is obtained, which allows to estimate the errors of determining the coordinates of the landmark using the flying platform with known errors in determining the observation point coordinates and the range determination of the range finder.

Nowadays, various types of geodetic measuring instruments are available in surveying. When conducting a survey of a terrain, surveyor must choose a survey method that is capable of providing high precision measurements. In the surveying process, it is possible to use the following measurement methods − tachymetric survey method, positioning method and remote sensing method. Each of the methods produces data formats that can be used further for volume calculations. The paper analyses the volume differences that are obtained when using various survey methods and volume calculation programs to obtain the surface model. The use of such a tool is important for useful mineral miners, so that surveyors make qualitative surveys and obtain accurate and reliable volumes. Useful minerals miners are required to report annually on their mining volume for a specified period. The useful minerals miners shall at all time keep records of the quantities of minerals actually extracted. Regardless of the type of accounting, topographic surveying and the calculation of volumes, if mineral is extracted in mineral deposits of national importance, more than 50 000 m**3, are required (Augstas detalizācijas topogrāfiskās…, 2012). High-quality and accurate topographic survey is needed to create the most realistic surface model appropriate to the terrain. It is defined that the difference between the volumes obtained from the recording of vehicle loads should not be more than 5% when comparing the result of the mineral extraction from topographic surveys (Derīgo izrakteņu ieguves…, 2012; Noteikumi par valsts…, 2018). Nowadays, various measurement methods can be used to obtain data from which a surface model can be generated, and this model can then be used for volume calculations. The surface model is a set of points where, in addition to plane coordinates (x and y), there is also altitude (z) known (Luukkonen, 2011). Each measurement method has its own different measuring instruments that can be used, each method has its own operating principles, on which the quality and accuracy of the obtained data depends.

The issue of the study of the problem of determining the geoid and quasi-geoid models is considered. Development of methods for constructing an exact geoid model using different dimensions. Analysis of the calculation of normal heights using satellite measurements, construction of geoid and quasi-geoid models by different methods is performed. Based on the results of the analytical review of existing methods for determining the geoid, it was proposed to use various data (geodetic heights, mixed gravity anomalies, anomalous potential) to construct this model, which allows building a model of a geoid with millimetre accuracy. The possibility of using the collocation method is considered. The task is to develop a methodology for constructing a geoid model using a network of low density gravity points and using pure and mixed gravity anomalies, which allows us to solve the problem of finding potential by solving the Laplace equation or using wavelets.