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The maintenance of a modern vertical reference system in Bulgaria, aligned with the European Vertical Reference System (EVRS) standards, is directly dependent on the precise knowledge of the Earth's gravity field. The research presented in this paper is motivated by the 5th cycle of the 1st order National Leveling Network (NLN) re-measurement, initiated in 2021, which involves complex observations across 55 leveling lines. The primary objective of this study is to evaluate the extent to which existing gravity reso...

This paper is focused on the verification of two quasi-geoid models for the territory of Bulgaria (the model integrated into the Geodesy, Cartography and Cadastre Agency (GCCA) official product for the transformation of geodetic data and a model derived using the GNSS/levelling method) through direct geodetic measurements. The study was developed in the framework of the current 5th cycle of the 1st Order National Levelling Network (NLN), conducted in accordance with the requirements of the new 2021 Instruction [1]...

The monitoring of the construction behavior is one of the important activities carried out to determine the state of construction, subject to various natural and anthropogenic actions at a given time. In Romania, the activity of rockfill dams monitoring is regulated according to the importance category (A, B, C). The Rausor Dam is located downstream of the confluence of the River Rausor with the river Targului, which springs from the Iezer - Papusa Mountains in the central part of Romania. Being part of importance...

Civil aircraft navigation uses specific procedures for the continuous determination of the aircraft position using the path and distance traveled in the considered time interval as calculation elements. Throughout the route, errors must be estimated that are generated by a series of parameters such as: hydrometeorological conditions, air current direction, declination, geoid parameters, the ship's nautical qualities and the response mode of the navigation equipment. The indications of the magnetic compass must be ...

Spatial data infrastructure is an essential tool for the management, planning, and analysis of sustainable development. The Latvian ecosystem, which consists of numerous decentralized resources, has successfully established a foundation by fulfilling the requirements of the European Union's INSPIRE and Open Data directives. The transition from a culture of viewing 'paper maps' to the automated machine processing of standardized, vectorized, and semantically rich data represents the primary benefit. To evaluate and...

UAV photogrammetry is well established in Slovak geodesy across all aspects of surveying work. To a lesser extent, it is also used for the purposes of the Slovak Land Administration System (LAS). The aim of this study was to analyze the advantages and disadvantages of obtaining coordinates of breakpoints of ownership boundaries from data acquired by UAV photogrammetry. Data collection took place in 2025 in the cadastral area of Pac, covering an area of 0.703 square km. The survey work lasted 4 hours using a DJI Ma...

This paper discusses the relevance of the classical adjustment weights for the highest-order geometric levelling network. The commonly used weights are inversely proportional to the length of levelling lines. The argument behind this choice is the assumption that the accuracy of measured elevations is a function of the square root of the levelled route. Therefore, the longer the line, the less its weight in the adjustment of the network. However, there are often events where the measured elevations of long lines a...

It is well established that the farther a benchmark is from the datum point in a leveling network, the greater its standard error of adjusted height tends to be. To explore the optimal datum point location for minimizing height uncertainty, we performed 11 separate adjustments of the Second Bulgarian Leveling Network. Each adjustment used a different nodal benchmark as the datum point. While all adjustments yielded identical benchmark elevations and the same mean adjustment error of 2.14 mm/km^0.5, the sum and ave...

Conventional salt mining creates large voids that disrupt geomechanical equilibrium, inducing subsidence pressures from overlying strata. This process, known as convergence, is the time-dependent closure of excavated spaces caused by salt-s viscoplastic behavior. Continuous convergence monitoring is critical for early detection of excessive strain, enabling timely mitigation to maintain structural stability and prevent hazards like water ingress and flooding. Due to the slow deformation rates of halite formations,...

This article examines the impact of electric and electromagnetic fields on the accuracy of GNSS technology, particularly in environments with overhead high-voltage and power lines. Although this factor is often overlooked, it can significantly affect the quality of received signals and, consequently, the accuracy of measurements. Electromagnetic interference caused by the presence of power lines can lead to signal distortions, reduced positioning reliability, and, in some cases, complete signal loss. The study foc...

Sea level change and global sea level rise are slow but persistent changes. They should be evaluated as a sign of ongoing climate changes. The Black Sea is a semi-enclosed sea, with the only connection to the world's oceans being the narrow Bosphorus Strait. The influence of climate changes in such an environment will be grater. Sea level observations on the Bulgarian part of the Black Sea are carried out by numerous tide gauge stations. The most indicative of them, with the most complete set of measurements, is t...

This paper presents the monitoring of an eroding phenomenon (gully) near Ciurila, Cluj County, Romania, using UAV (Unmanned Aerial Vehicle) and GNSS (Global Navigation Satellite System) technologies. In this sense, the monitoring results through sustainable and non-invasive technologies are presented, following four cycles of observations, carried out between June 2019 and April 2021. The paper aims to present the advantages and limitations of such a study, as well as the importance of monitoring erosion phenomena...

Constructions extending over large areas or distances raise problems regarding their setting out, because these elements are determined in the official projection of Romania, namely the 1970 Stereographic map projection. For the territory of our country, this produces distortions from -25 cm/km to approximately +64 cm/km in terms of distances and between -5 sq. m/ha and +12.76 sq. m/ha in terms of areas, depending on the distance from the projection pole and, implicitly, from the circle of zero distortions. For th...

The paper presents a quality evaluation of the kinematic model concerning the relative height movement of the Earth-s crust that refers to the territory of the Republic of Croatia. This kinematic model enables determination of vertical displacements and movement speeds of discrete points on the Earth-s crust. So far, the quality of the model has been rated only for certain parts of the Croatian territory, but this paper shows the results of the model-s quality evaluation for the entire territory of the Republic of...

Underground mining operation in salt deposits requires special control over rock mass stability. Changes in stress within the rock mass cause gradual convergence of underground workings. A slow convergence process with a complex spatiotemporal distribution requires the measurements with high accuracy, which is carry out on a well-planned spatial distribution of observation network. The aim of the study was to present the procedure of designing and implementing observations of convergence in salt caverns within a s...

The use of digital twin models in immovable culture heritage enables better decisionmaking about preventive maintenance, heritage management, and interpretation, as well as accurate digital documentation. This publication discusses an approach for creating a digital twin using different methods of spatial data acquisition: close range terrestrial digital photogrammetry, aerial digital photogrammetry and terrestrial laser scanning. The "Holy Transfiguration" Church in Pomorie, Bulgaria which is the oldest functioni...

In recent years GNSS studies play an increasing role in studding of natural risk hazards and active tectonics. The area of Sofia is part of the broad South-Balkan Extensional Tectonic System. This highly populated area of economic significance, even showing to be not so active as other parts of the System is also affected by natural hazards, as active seismicity, landslides, rock falls, debris, etc. GNSS studies are extremely important for understanding of natural hazards and recent geodynamics of the area, especi...

The monitoring of geodynamic processes with modern GNSS technology in the area of Sofia and Southwest Bulgaria has been going on for more than 25 years. To investigate modern crustal motions in the area, GNSS data obtained between 1996 and 2022 are analyzed to obtain the velocity field for southwestern Bulgaria. Every year, measurements are carried out on a part of the points, and the last measurements were carried out in 2022. For the entire period, monitoring covered 28 stations. To evaluate the new result for t...

The purpose of this study is the analysis of the dynamics of tectonic movements accompanied by two strong seismic events that occurred in the Durres area (Albania) in September-November 2019, through the use of GNSS technology, applied to national permanent satellite geodetic networks. Previous studies have been carried out on our study area by foreign authors from Croatia, Greece, and Italy. For our study case, we relied on geodetic weekly data secured from the Bulletins of Italian and Austrian stations, BSW52, o...

In this study, we aim to demonstrate the change in the topography of the sea floor as a result of the sedimentation of rivers. The study area is the Divjaka Bay, bounded to the north by the delta of the Shkumbin River and to the south by the delta of the Seman River, on the Adriatic coast of Albania. The method used is the Integrated Satellite Bathymetric Surveying method. The monitoring period extends from 2017 to 2020, based on 4 monitoring campaigns. The longitudinal bathymetric profile extends northsouth, in p...

The field of construction is currently one of the most stable and active fields of activity. It presents complex activities that are done in phase and chronologically until the end of completion execution stage. Realization of the foundation or its characteristic elements it includes a number of preparatory activities such as: land preparation and release of various tasks, shoveling and ground consolidation. The type of consolidation it is chosen according to the depth of the escape and It is about choosing a supp...

The article summarizes the main geodetic activities performed in the region of Southwestern Bulgaria to study the modern crustal movements and clarify the geodynamic situation of the region. The study area is bounded to the north of the southern slopes of the Balkan Mountains, to the south to the southern slopes of the Rila Mountains, to the west - the western border of Bulgaria and to the east - the beginning of the Upper Thracian plain. The area has a complex geological structure with many active faults that mus...

The new network of permanent GNSS (Global Navigation Satellite System) stations should be established by the end of this year. At the moment, 18 permanent stations are already established. All stations coordinates must be determined following the conditions dictated by the Republic Geodetic Authority of Serbia, i.e., the Rule Book for establishing the GNSS permanent stations network. The coordinates of stations, the final solution, must be calculated from three consecutive uninterrupted daily sessions as a combine...

In 2004, a digital terrain model (DTM) was created in Serbia. It was obtained by vectorizing isohypses on topographic maps with a scale of 1: 25000. The resolution of the digital model of Serbia is 30 m, and the vertical accuracy, as the authors claim, is 10 m. From December 2021, the global model FABDEM (Forest And Buildings removed Copernicus DEM) is available to the public. It was created based on the data of the Copernicus GLO30 model so that data on forests and buildings were removed from it. Important featur...

The purpose of the paper is to perform a topographic lifting and traction of an architectural project for the execution of a Tyrolean that is arranged on various relief forms, in a hilly area, halfway between Timisoara and Lugoj, Timis County, Romania. The development of an adventure park in an area so close to urban settlements has a great impact on the public of all age categories. Children are the main beneficiaries of such objectives because they test their minds and, at the same time, implement an active and ...

This paper covers the activities of creating a database for the study of modern crustal movements in the region of Sofia and Southwestern Bulgaria, including data from GNSS measurements of the geodynamic network and the results of their processing and analysis, data from permanent stations and archive data from Synthetic-aperture radar, processing and obtaining interferometric images. The local archive of GNSS measurement includes: manual sketches of the location of the points; log sheets of the measurement with i...

The theme of the work aimed to present a model of drawing up and carrying out a drawing work for collective constructions in order to build a building with a ground floor + 1st floor + attic. This project has been approved by the City Hall of Timisoara, Romania. The purpose of the work was to identify and execute a topographic elevation, to draw and track the horizontality and verticality of the building for each level (ground floor, floor, attic). The work was completed with the preparation of a cadastral documen...

The structural analysis of the civil infrastructure is vital in order to track the evolution of degradation in time, to prevent disasters, but also to document and conserve the sites of cultural heritage. This paper review-s the workflow on the acquisition of point clouds to Terrestrial Laser Scanner (TLS) with those collected by photogrammetric 3D models based on images captured by an unmanned aerial vehicle (UAV), analyzing the data sets on two diferent type of bridges located in western Romania. The obtained da...

GNSS technology evolves at a fast pace and, along with it, the number of applications that are based on this technology increases. An important part of the applicability of GNSS technology is in the field of geodesy. In this article we propose to present a GNSS system that is built starting from the U-blox ZED-F9P receiver, integrated on a development board produced by SparkFun that is connected to the Raspberry Pi 4 Model B single-board computer. The Raspberry Pi computer and the development board made by SparkFu...

The data obtained from the monitoring of the dam’s behavior, allow to make the decisions to start the current maintenance works at the best moments of time. They also make it possible to know from early stages possible atypical behavioral phenomena and to take measures accordingly before such phenomena become dangerous for the safety of the construction. One of the ways to monitor constructions is to perform geodetic measurements at different stages and to compare the coordinates obtained in a coordinate reference...

The paper analyzes normal corrections for the determination of the normal height differences along the First Order Levelling lines in Bulgaria. Normal corrections are calculated in two ways – with measured gravity accelerations and with gravity data from Global Geopotential Models (GGM). The study uses the last contemporary GGMs developed up to 2160-2190 degree and ultra-high resolution GGMPlus model. Calculations for Bouguer anomalies are made by the calculation service in the International Centre for Global Eart...

Along with creating modern infrastructure facilities in Moscow, 9-storey building with a multi-level underground unit is being constructed in the central part of the city. Partial preservation of the structures of existing historical facades of buildings is provided during construction. Buildings, structures of the surrounding development and dense network of underground utilities fall into the zone of construction influence. Taking into account the construction in conditions of dense urban development, near exist...

Calculation of normal heights and differences from known geopotential numbers and differences in geodetic practice is required when performing independent calculations: for control of levelling network adjustment made with different type heights – normal and geopotential; when using optical clocks technology for geopotential difference determinations; when performing precise engineering and geodetic works. It is well known that between two height types - normal heights and geopotential numbers exists theoretical e...

The objective of this research is to optimize the volume of laboratory tests of physical and mechanical properties of soil. Today, the solution to geomechanical and mining technological problems has the form of functional or statistical relationships, reasoned by the physical parameters of soils (density, moisture, strength properties, acoustic indicators, etc.). The calculations use the average values or estimates of these parameters obtained from statistical processing of multiple laboratory or field test data. ...

The Bulgarian northern Black Sea coast is affected by many landslides. Several geodynamic networks have been built to study landslide processes in the northern Black Sea coast. Landslide research is important, as these phenomena can lead to great material damage. Their destructive impact on buildings, engineering structures and disturbances in the resilience of the earth's crust causes enormous economic, environmental, social and other damage, and often takes human lives. A modern tool for monitoring landslides is...

Globally, modern crustal movements are being studied as a priority, a large number of projects are being developed and significant funds are being allocated for the development of research in this field of science. Due to the social importance of the problem, the need to obtain geodetic data on the current activity of the earth's crust is realized. This article examines the study of the temporal movements of the earth's crust and the accumulated stresses in a geologically and seismically active region with the pre...

QDaedalus systems are currently used for astronomical observations to obtain astrogeodetic vertical deflections (VDs). Astronomical observations cannot be made under the same conditions as geodetic observations (e.g., GNSS), because meteorological factors (e.g., cloud cover during observation, high humidity, fog, etc.) and timing of the observations may directly affect the observed benchmarks, particularly regarding precision and accuracy determinations of the VD components observed with the QDaedalus system. For ...

The region of southwest Bulgaria is characterized by a large number of fault structures, and the presence of tectonic and seismic activity, thus predetermines the development of dangerous geodynamic processes. This article discusses the estimates of modern movements of the earth's crust obtained from periodic geodetic measurements. They describe the total effect of fast and slow horizontal and vertical movements. Obtaining such estimates, on the order of mm/y, requires determining the coordinates of the points of ...

During the process of drilling wells with a complex spatial profile, it is necessary to obtain timely information about technological processes in order to control them. This issue is relevant for the oil and gas industry, since the number of works of increased complexity is constantly growing. This article discusses the technique of vertical tomography in control problems during directional well drilling. The object of control in this case is the technological equipment, the well and the surrounding soil. The art...

There is observational evidence that the global sea levels are rising and increasing the risk to coastal communities from floods and erosion. Interest in marine sea level research is determine not only by forecasting cataclysms and sea level rising, but also in connection with interdisciplinary studies exploring the causes of this change. The article outlines time series analysis of tide gauge data to solve for short and long-term sea level variations at Varna and Burgas tide gauge stations. The data covered the p...

The constructive solutions proposed for the realization of constructions must take into account the existing situation on site and the way of manifesting of as many factors that can influence the functionality of the building as possible. When functional deficiencies occur during the construction operation, they must be located immediately, the causal factors must be identified sooner rather than later and measures must be taken to eliminate their effects. The activity of building monitoring is aimed at monitoring...

The global development of science and technology encourages many countries to use their own modern coordinate systems, determined on the basis of satellite measurements. At the same time, the modern system should be characterized by its openness and unity for the entire territory of the country. One of the main problems arising in the creation and operation of its own high-precision positioning satellite systems in the Republic of Kazakhstan are the lack of domestic satellite equipment, specialized software and te...

Often, during the analysis of the Recent vertical motions of the Earth?s crust, it?s operating by the knots of the benchmarks in networks with different range. Usually, various models of a dynamic behavior of the benchmarks are postulating. But there isn?t a model, which is not devoid with indefinable in translation. The problem with indefinable is corresponding with the problem for a choice of a fundamental (?immovable?) benchmark. For an ?immovable? benchmark could be chosen an arbitrary benchmark in the network...

Systematic monitoring of buildings and structures is necessary to ensure the safety and reliable functioning of infrastructure facilities. An important component for high-precision measurement control during monitoring is the verification of double measurement accuracy and the identification of systematic errors. By double measurements we mean the comparison of measurement result difference between the monitoring series, determining the displacements that occurred as systematic errors using the mathematical appara...

The influence of the temperature fluctuations on the staffs for precise levelling are investigated. The investigations are realized on a real levelling line in the State levelling network of RBulgaria. There is analyzed the influence of the temperature extension of the staffs on the whole height difference between the outlying benchmarks of the line and on the three intermediate sections: with representative low temperatures; with a various, from topographic point of view, terrain and with a sharply temperature ch...

Through this work we have created two geodesic support networks of the V order in the peat area of Poiana Stampei commune, supporting the subsequent topographic elevations of both the railway and its auxiliary elements, as well as the adjacent areas, be they forest boundaries, fences, etc. .a .. After materializing and making observations, it is necessary to compensate the networks to obtain the final coordinates of the points that will serve the subsequent topographic surveys and the topographic plans. In order t...

The study of recent crustal movements is one of the priority areas of the Earth sciences. Geodetic methods occupy a particularly important place in the general complex of measurements and investigations of crustal movements because they provide quantitative information on the condition and development of geodynamic processes. The paper outlines the newly accepted project with main goal monitoring the geodynamic processes in the area of Sofia. This goal will achieve by periodic GNSS measurements over the Sofia geod...

The study of landslides is of particular importance because they can lead to great material damage. The region of the Bulgarian northern Black Sea coast is affected by many landslides and it is important to monitor motions of the major landslides in this area. The paper outline deformation analysis of the landslide processes in the area of ?Dalgiya yar?. It is a landslide circus from the Varna landslide region that covers several active landslides, whose boundaries are overlapping and for that reason are difficult...

The main, officially regulated, stages of creating and maintenance of a cadastral map are presented. Accentuation is placed on the technology, used for measurement of cadastral objects during the last recent decades. A comparison between the technological potential of Terrestrial Laser Scanning - technology and the legally approved technologies is done. Practical experiments for determining of the applicability of the Terrestrial Laser Scanning ? technology for the purposes of the cadaster are implemented. Surveys...

The precise point positioning (PPP) method is a relatively young method of GNSS observations processing but it is already quite widespread in many cases. However, the processing of observations with this method using specialized software requires some experience and competencies. The advent of web services for processing the results of observations using the PPP method significantly simplified this task. This circumstance is especially important for workers in the cadastral sphere, and makes it possible to simplif...