Geodetic Network Research Articles

Applying Geomatics Techniques for Documenting Heritage Buildings in Aswan Region, Egypt: A Case Study of the Temple of Abu Simbel

It has recently become more popular to involve 3-D modeling and digital documentation in the conservation and restoration of heritage sites. The main objective of the current study is to develop a digital documentation process using laser scanning for Abu Simbel Temple, which is one of the most famous archaeological sites in Egypt. We focus on these techniques to replace traditional methods of building heritage documentation. To create the 3-D model with geographic coordinates and measure the rate of deformation, a precise geodetic network of five points was established around the temple. Then, 52 scans of the temple facade and its interior parts were taken using a Trimble TX6 laser scanner. This led to the creation of a 3-D digital model of the temple that includes geometric, structural, architectural, historical data, and non-engineering information (such as appearance, inscriptions, and material details). The 3-D point cloud model outputs exhibit a 6 mm spacing between the points with an error of 4 mm and a standard deviation of 5 mm. In addition, the temple’s virtual tour included 61 panoramic images. This virtual tour can help to increase heritage awareness, promote tourism, and aid in the future restoration of any parts vulnerable to damage.

RETROSPECTIVE STUDY OF VERTICAL GROUND DEFORMATION IN COMO, NORTHERN ITALY: INTEGRATION OF LEVELLING AND PSI MEASUREMENTS

Abstract. Subsidence-related vertical ground deformation due to natural and anthropogenic factors may lead to considerable damages to structures and infrastructures, and may increase the occurrence probability of consequential events, such as floods, especially on sea and lake shores. Como city, placed in the north of Italy, adjacent to Como Lake, is subjected to significant subsidence phenomenon, which has been monitored by geodetic levelling networks. In this work the historical geodetic levelling measurements and satellite-based Synthetic Aperture Radar (SAR) data archive are integrated to assess the accuracy of Atmospheric Delay and Deformation Rate estimations obtained through Persistent Scatter Interferometry (PSI) techniques. Tree levelling measurement datasets acquired in 1990, 1997 and 2004 are used in order to obtain the precise deformation rate at the benchmarks for two periods of 1990–1997 and 1997–2004. For multi-temporal InSAR analysis, 106 SAR images (1992–2004) and 41 SAR images (1992–2004) in Ascending Track orbit from ERS-1/2 missions are used in this study. The assessment is performed through a statistical comparison between two sets of vertical land deformation rates obtained by integrated methods. The results of the validation represented a good consistency between deformation rates derived by both techniques. Also, this study has revealed the potential of SAR images acquired in gyro-less mode by ERS-2 mission (2001–2004) in terms of the estimation of ground deformation.

On the exact and efficient solution of the Huber function for measurement applications

The findings of this paper are summarized as follows: (1) We point out that the recently published conclusion that Iteratively Reweighted Least-Squares (IRLS) cannot guarantee the global solution of the well-known Huber function is incorrect. We present that the Huber function has only one minimum and IRLS will obtain the exact minimum unless it is incorrectly implemented. (2) We revisit the variants of the IRLS algorithm and compare them with the exact IRLS algorithm in the geodetic free trilateration networks adjustment. Notably, the pointwise differences between the variants of IRLS and the exact IRLS are even beyond the differences between the Least-Squares solution and the exact IRLS for over 75% points. (3) For rigorously and efficiently solving the Huber M−estimation problem, we propose the Quasi-Newton approach and its limited memory version. The time expense of our proposed algorithm is quite low compared with the time expense of the existing exact IRLS in the cases of a large number of unknown parameters and observations. Our results show that the computation efficiency is improved by one or two orders of magnitude.

Modificirana metoda deformacijske analize po postopku München

Despite the technical progress monitoring the stability of engineering structures remains one of the most difficult tasks in engineering geodesy. This article presents the deformation analysis according to the Munich approach of W. M. Welsch. The method deals with the testing of the geodetic network's congruence, the affinity of selected triangles, and the testing of other kinematic parameters in 2D geodetic networks. Deformation analysis using the Munich approach can be performed using the X-method, which is based on the comparison of the coordinates of identical points in the geodetic network between two sets of measurements that depend on the geodetic datum, or using the L-method, which determines changes in the values of lengths and angles which are quantities independent of the geodetic datum. In the modified method, we propose to determine the congruence of all lengths and all angles in the network between two sets of measurements and to determine the congruence of all triangles between points in the network, not only selected ones, as it is common in the classical approach of deformation analysis based on the Munich approach. The proposed improvements are tested on the example of a known hexagon, and an analysis is made of the success of detecting stable points in the network using the classical Munich approach. In the present case, the results of the proposed method did not differ from the results of other deformation analysis methods.

Equalization of free geodetic networks by search methods for geodetic monitoring of structures in arctic areas

While carrying out work to ensure the technical safety of buildings and structures in the Arctic regions, one of the important stages is geodetic monitoring. Provided that the complexity of ensuring the stability of reference points in the Arctic zone when conducting geodetic monitoring of engineering facilities, geodetic networks should preferably be equated as free, i.e., to equate the reference points on a par with the defined ones. The present article provides variants how to to equalize geodetic networks to carry out a search method of non-linear programming, which is given a theoretical substantiation for the method and the order of estimating accuracy of the outcomes of the equalization of the generalized Makarov method. The procedure of pseudo transformation of a matrix of normal equations of unknowns with the application of an algorithm of a search method of nonlinear programming is given. The correctness of the application of the search method to the pseudo transformation of a matrix of normal equations of unknowns by the coincidence of outcomes of the pseudo transformation of the given matrix based on skeleton expansion done in M. Mashimov's work is proved. Equalization and estimation of accuracy of free leveling network with the application of search method and generalized Makarov's method are carried out. The conclusion about the correctness of the application of a search method of nonlinear programming for the processing of free geodetic networks at the performance of geodetic monitoring of buildings and constructions in the Arctic area is made.

THE IMPLEMENTATION OF ROAD DESIGN ENGINEERING SURVEY STUDIES BY SATELLITE AND ELECTRONIC TECHNOLOGIES

The basic geodetic networks created for engineering geodetic surveys of road construction are presented using polygonometric and satellite technics. The key components of the route, the horizontal and vertical circular curves, and the marking work to move them to the site are all provided. Both the satellite technic using GPS satellite receivers and the polygonometric method of building fundamental geodetic networks were taken into consideration. It has been grounded that the satellite method, which, when used, reduces human resources, saves financial resources, and shortens the time of work implementation, is the most efficient way to build fundamental geodetic networks.

Основные направления развития государственной координатной основы в Афганистане

The review of the current state of the Afghanistan state coordinate framework, created by both ground and satellite methods, is carried out. It is outlined that when developing the geodetic network of Afghanistan, it is useful to use the experience existing in other countries, but taking into account the territorial characteristics of the state. The basic development directions of the state coordinate framework are formulated: the choice of the state coordinate system and its implementation, the creation of geodynamic polygons, the installation of continuously operating reference stations (CORS) of GNSS. It is recommended to use high-precision differential correction services in inaccessible areas to determine coordinates using GNSS methods. Based on the proposals formulated, it will be possible to create a highly accurate sustainable and developing state geodetic network on the territory of Afghanistan to perform topographic and geodetic works for various purposes, geospatial monitoring, mapping, geodynamic research.

Geodetic network for the construction of the high-speed railway line

Geodetic support for construction and operation of high-speed railways requires high-precision geodetic work both at the construction stage and during operation of the structure. Geodetic separation network, being the basis of mainline construction, requires special care and accuracy in measurements for its creation. The analysis of studies carried out in this field shows their insufficiency or incorrectness, and the comparison of current rules and regulations documents shows their contradiction. In the article, based on the results of existing scientific works, on the basis of the allowable standard values of outstanding lateral accelerations, the necessary accuracy of building a marking network for the construction of a railway line with speeds up to 400 km/h is calculated. On the basis of the analysis of existing regulatory documents of various countries engaged in high-speed rail traffic, the correctness of the obtained result has been proved. The imperfection of the Russian normative base in the field of construction of such objects is shown. Based on the findings, practical recommendations are given on methods for constructing a planned network for the construction of a high-speed highway and fixing its points, which can significantly reduce the cost and intensity of work on its creation, as well as directions for further necessary research in the field of geodetic support for the construction of high-speed highways.

ИНФОРМАЦИОННЫЙ ПОТЕНЦИАЛ И ВОЗМОЖНОСТИ БАЗЫ ДАННЫХ И ГИС-СИСТЕМЫ НАСЕЛЕННЫХ ПУНКТОВ ПРИЕНИСЕЙСКОЙ СИБИРИ (СЕРЕДИНА XIX – НАЧАЛО ХХ ВЕКА) В СВЕТЕ СОВРЕМЕННОЙ РЕГИОНАЛИСТИКИ

The paper explores the information potential and capabilities of the database and GIS system for systematic research on the localities of Yenisei Siberia in the mid-19th – early 20th centuries, with a focus on regional studies. The study examines Siberia as a full-fledged part of Russia and its Asian periphery. The Russian government changed the policy towards Siberia from minimal intervention to targeted economic colonization, involving voluntary migrations and the unification of the settlement structures in vast uninhabited spaces. In addition to the so-called river settlement structure (Yenisei region) or the nest settlement one (Priangara), the formation of a planned, geographically closed structure started. The paper highlights the gradual replacement of small settlements such as graveyards (‘pogost’), evictions (‘visel’), and single-yards (‘zaimka’) settlements with ordinary villages, the stratification of old-time residents’ space and the emergence of resettlement settlements, and the division of traditional settlements. This process includes increasingly remote territories of Siberia, such as the Yenisei North. The author demonstrates that the problems of space development and center-periphery relationships are relevant at the present time. The paper employs statistical, historical, geographical, and cartographic methods. Modern statistical analysis techniques reveal the spatial dynamics of the region's development. The reasons for the formation of the structure of the database hierarchy based on the geographical factor and the combination of information with interactive maps are under investigation. The paper describes the attribute tables of settlements, and plotting geodetic and hydrographic networks. The principles of dataset formation based on various reference books are outlined. The author concludes that the dataset has the potential to combine source-oriented and problem-oriented approaches, and it gives the possibility to place both historical and actual relevant data in a comprehensive information resource.

О точности разбивочной сети для строительства высокоскоростной железнодорожной магистрали

Geodetic support for the construction and operation of high-speed railway lines requires high-precision geodetic work both at the construction stage and during the operation of the facility. The ge-odetic setting-out network, being the basis for the construction of the highway, requires special care and high measurement accuracy for its creation. An analysis of the studies performed in this area shows their insufficiency or incorrectness, and a comparison of current regulatory documents shows their inconsistency. In this article it is calculated on the basis of the results of existing scientific works what should be the required accuracy of building a planned setting-out network for the construction of a railway with speeds up to 400 km/h. The correctness of the result obtained has been proved based on the analysis of existing regulatory documents of various countries providing high-speed rail communication. Based on the findings, practical recommendations on methods for constructing a planned setting-out network for the construction of a high-speed railway and fixing its points are given, which can significantly reduce the cost and labor intensity of work on its creation. The imperfection of the Russian regulatory framework in the field of construction of such facilities as well as the direction of further necessary research in the field of geodetic support for their construction are shown.

Metrica – An application for collecting and navigating to geodetic control network points. Part II: Practical verification

Abstract To prepare the mobile application for the ongoing update of the control network, it is necessary to define detailed procedures for dealing with the points database. These procedures concern the determination of the methodology of making an inventory of the existing database and then the determination of the rules for updating the control network using the developed application. This part describes a practical verification of Metrica for collecting control points data and showing specific cases in the collection and sharing of such data. There were created field inspections using nine different criteria on the set of selected points. Analysis shows that a large part of the points need to be reviewed once again, and its description needs to be updated.

Геодезическое обеспечение выверки формы отражающей поверхности главного зеркала радиотелескопа с применением лазерных трекеров

The article discusses the possibilities of coordinate-determining technology using high-precision geodetic instruments for alignment of reflecting surface shape of the radio telescope main mirror. It’s important for adjustment of reflecting surface shape and consequently performance of radio astronomy observations. The article provides general information about radio telescopes and consideres the existing classical geodesic and non-geodesic methods used in the process of solving the problem of shape alignment. The text describes the method of geodetic work on the form alignment using high-precision laser trackers. The methodology includes several stages from designing the geodetic control network and tracker location stations and processing and interpreting the measurement results. The conditions for performing high-precision measurements are given in the thesis. Mathematical processing of measurement results is performed in the Spatial Analyzer and based on coordinate systems transformation.

Structural design of satellite geodetic networks using mobile monitoring stations

The article considers a method for solving the problem of structural design of modernized networks of non-request measuring instruments of a ground-based control complex for navigation stations of a space complex. The object of research is satellite geodetic networks using mobile monitoring stations. The type of such networks is information and control systems distributed over the territory, dispersed in space. Structurally, they are determined by multifunctional sets of stationary and mobile elements with advanced technical means for receiving, transmitting and processing information. It is shown that in the structural design of satellite geodetic networks, special attention is paid to the cost of the network, since this can significantly reduce the cost of field work associated with the use of mobile monitoring stations. An analysis of various approaches to the formation of the structure of such systems was carried out, which showed that the tasks of formation can be divided into two groups: the formation of the topological structure of the system and the formation of the functional structure of the system. The paper presents the stages of the analytical and simulation procedure, which includes optimization and simulation models and allows solving the problem of structural design of satellite geodetic networks.

Deformation analysis of Ratkov Laz bridge using Pelzer and IWST method

The paper discusses the application of geodetic methods of deformation analysis of reinforced concrete structures made of prestressed concrete. In the paper, two independent methods of deformation analysis are applied on the example of the Ratkov Laz bridge in Montenegro, based on two epochs of geodetic measurements in a 3D geodetic network, which consists of the reference part of the network and points on the bridge. The results of the Pelzer’s method and the robust IWST method were analyzed. Although similar displacement vectors are obtained using the two methods, there are some differences in the identification of unstable points on the bridge. The IWST method identified significantly fewer points as unstable compared to the Pelzer’s method. The aforementioned methods of deformation analysis are of great importance in the geodetic observation of all types of engineering facilities.

Monitoring Coastal Landslides along the Northeast Black Sea of Bulgaria Using SAR data

The geological conditions along the Northeast Black sea coast of Bulgaria are favorable for landslides emergence and development. Those processes have been rigorously documented in the last fifty years by Earth science researchers. Their efforts contributed in a broader context to the landscape conservation and to mitigate the risks for the population caused by the mentioned surface disruptions. In this paper the obtained results record the temporal behavior of several landslides located in stated region during the last five years. The main data source to monitor the mentioned landslides are data from synthetic aperture radar (SAR) instrument processed by the differential interferometric SAR (DInSAR) method. The produced results were validated by means of global navigation satellite system (GNSS) measurements carried out at purposely created geodetic networks, satellite images with high spatial resolution and digital images obtained by unmanned aerial systems (UASs). The results presented in this paper unambiguously confirm the usability of the produced information for the local authorities and other stakeholders thus contributing to the improvement of landslide risk management practices and to the better planning of the territory where the researched landslides are located.

The use of VIKOR Method in Finding the Optimal Solution for a Special-Purpose Geodetic Network Design

This study deals with the use of VIKOR method in finding the optimal solution for a special-purpose geodetic network design. It is about a multi-criteria compromise ranking method developed in 1986. Based on previously defined criteria functions related to precision and reliability, four acceptable alternative solutions were firstly established. Then, with the aim of finding the optimal one, those solutions were subjected to VIKOR method. The geodetic micro-network used in this study was simulated as a trilateration one and consisted of six control points discretizing a structural geometry as well as four, five or six reference points (pillars), depending on what alternative solution it was about. The optimal network design should have ensured the detection of deviations of the control points' positions in accordance with a priori introduced tolerances and constraints. It turned out the approach based on VIKOR method is a very efficient tool in tasks involving multiple conflicting requirements referred to a geodetic engineer and in the cases when the decision must be made in a short term.

3D data integration for geo-located cave mapping based on unmanned aerial vehicle and terrestrial laser scanner data

The Akçakale cave is a significant natural and cultural heritage site in the Black Sea region of eastern Turkey. The complex geometry and difficult-to-access areas of the cave have made the use of traditional mapping methods challenging. To overcome these limitations, this study utilized TLS and UAV technology to produce highly accurate 2D and 3D data for cave management and risk assessment purposes. The TLS system was used to create a detailed 3D point cloud of the cave interior, while the UAV system generated a 3D model of the surface topography outside the cave. The two sets of data were combined in the GIS environment using a geodetic network established in the study area, providing a common geodetic reference system for both TLS and UAV data. The study found that the cave area is 13,750 m2, which is smaller than the area of 18,000 m2 that was previously estimated using conventional measurement methods. The volume and ceiling heights of the cave were calculated using the elevation models generated from TLS point cloud data. The 3D point cloud data were also used to map dripstone locations on the floor and ceiling of the cave, and the boundaries of rock blocks on the ground were precisely determined. The study identified potential risks associated with the cave, particularly the risk of rockfall in the source rock areas around the cave entrance and the southern part of the cave. The nearest building to the cave is approximately 35 meters away, and all the buildings in the area are less than 300 meters from the cave. In the event of the cave collapse, the buildings in the southern part of the cave are at risk of rockfall. This study demonstrates the effectiveness of combining data from TLS and UAV systems to generate broad and sensitive cave mapping and risk assessment data, which are critical for cave management and safety. The collected data can be used for cave stability investigations and rockfall risk assessments. This study provides a foundation for future explorations of the Akcakale cave and highlights the potential for modern surveying techniques to enhance our understanding of complex geological structures such as caves.

Использование методики спутникового нивелирования при создании высотной сети на территории Ливана

The article deals with the issue of using satellite leveling technology to create referenced height networks. The topic is relevant with the possibility of determining normal heights according to satellite determinations. At the same time, ensuring that the appropriate accuracy is associated with the solution of technological and computational problems. The first one is connected with the formulation of experimental studies to clarify the degree of variability of the reference surfaces, on which the transfer of the mark depends on the geometric leveling method. The second one is aimed to clarify the quasi-geoid marks for certain territories according to satellite determinations, quasi-geoid model, and geometric leveling. The use of satellite leveling technology is especially appropriate for countries with either no existing state geodetic network, or an undeveloped one, which in turns prevents finding a full-fledged solution of the practical problems. The presented method of satellite leveling includes the analysis of the deviations accuracy from the plumb line. An example of testing the methodology in Lebanon is given.

Metrica – an application for collecting and navigating geodetic control network points. Part I: Motivation, assumptions, and issues

Abstract The result of surveys largely depends on the accuracy and measurement technique of the control network. This research work presents the application Metrica, dedicated for collection and navigation of geodetic control network points. The main goal of this study is to present the motivation, methodology, and issues with analysis of the database of vertical control points. Such analysis covers south part of Poland territory for the update of the existing set of points of the vertical control network on an ongoing basis. The application has been developed with the use of a test database of points. The status of the points was checked by means of a multi-stage analysis. The prepared database of points was verified taking into account the criteria defined by the authors. In order to optimise the scoring analysis process, two groups of criteria were distinguished: independent of each other and those whose analysis was justified only under the condition of prior verification of other criteria. Based on the analysis of the collected data, the main conclusion was the ongoing need to update the data on the matrix points. It was found that information on points is often incomplete and inaccurate, especially in terms of their horizontal position, which often prevents efficient localisation of points. One of the most significant findings was that only 55.6% of the points available in the database were identified in the field. It should be noted that despite the analysis of the state of the matrix carried out in 2019 on behalf of the GUGiK, there are still many points about which information is not fully up-to-date. It is now possible to extend the application with new attributes and validation rules and conduct updates for several types of geodetic networks. Due to the extensive character of the discussed subject, the study has been divided into two parts. The continuation of this study is the second research work, which presents the development of a mobile application for the update of the geodetic control network. It will present in detail the procedures and IT application development processes.

Определение точности геодезических измерений при реконструкции исторических объектов

Purpose: To consider the issue of the assignment of marking work accuracy at reconstruction stage of a technically complex object. To show the need in accuracy preliminary calculation. After the assignment of geodetic measurement accuracy, to perform geodetic network designing in Credo.dat software package. To determine leveling class that satisfies formed requirements. Methods: Measurement error theory, least squares method, parametric adjustment method, modeling of geodetic networks using package of applied programs. Results: Requirements for the accuracy of marking works were established based on the ones of current regulatory documents. The sequence of the formation of requirements for definition of accuracy in geodetic staking base locations and requirements for the accuracy of used geodetic instruments is considered. Separately, the accuracy of planned and altitudinal geodetic networks is calculated. The possibility to apply class III leveling program when creating altitudinal network to meet accuracy established requirements is shown. Practical significance: The sequence of geodetic work accuracy assignment during historical object reconstruction is outlined on a particular example, the proposed methodology can be recommended for a practical use.