Geodetic Instruments Research Articles

Geophysical Borehole Observatory at the North Anatolian Fault in the Eastern Sea of Marmara (GONAF): initial results

Given its intense seismic activity and damaging earthquake generation potential, the western part of the North Anatolian Fault constitutes a serious natural hazard. As a result, the fault is monitored with a broad range of seismological and geodetic instrumentation making it a natural laboratory environment for scientific studies. One of the long-term projects in this region is GONAF (Geophysical Borehole Observatory at the North Anatolian Fault) which is the first borehole seismometer network project in Turkey. GONAF is a joint research project that started in 2011 as joint initiative of the Turkish Ministry of Interior, Disaster and Emergency Management Presidency AFAD and GFZ and the German Research Center for Geoscience Helmholtz Center Potsdam. The aim of GONAF is to detect, examine, and monitor the microseismic activity in the region and to observe the physical processes before, during and after a large Marmara earthquake (M > 7.0) that is expected to rupture the western part of the North Anatolian Fault, below the Marmara Sea along the Princes Islands segment or even further to the west. For this purpose, the permanent GONAF observatory was established consisting of 7 borehole seismometer arrays installed down to a depth of 300 m. In this paper, we report on regional stress changes in the western part of the North Anatolian Fault Zone (NAFZ) using instrumental data and the Coulomb stress method. We also present preliminary results of the observation and evaluation of microseismic activity obtained from the GONAF observatory. For the automatic evaluation of real-time data, Seiscomp3, RTQUAKE, and Earthworm Softwares were used. Within the scope of automatic earthquake detection studies, between March, 2016 and November, 2017, a total of 2568 earthquakes were detected using the RTQUAKE software. Of these, 1459 could be analyzed. While the magnitude of the analyzed earthquakes varies between 0.8 and 4.2, the depth of these events ranges from 2 to 30 km.

Geodesy and modern technologies

Currently, a lot of geodetic instruments and new geodetic technologies have been created, which are fundamentally different from traditional ones. In previous years, each type of measurement had its own type of instrument: for the angular measurements, the theodolite, for high-altitude measurements - a level, for linear measurements - a tape measure and rangefinder. Each device, depending on the intended use, had its own accuracy characteristics. Over time, science is developing and technologies are moving forward, the devices used in the field of engineering and geodetic works are improving. A modern geodetic instrument is a product of new technologies that embodies the latest achievements in optics and modern satellite technologies. This article provides a classification of devices according to their purpose and describes their application.

A Full‐Spectrum Bedrock Thermal Expansion Model and Its Impact on the Global Positioning System Height Time Series

AbstractBedrock thermal expansion includes prominent seasonal (annual and semiannual) terms and intricate nonseasonal variations (high‐frequency change and transient signals). However, the nonseasonal variations are usually ignored in geodetic studies due to defects in analytical solutions. In this study, we calculate the full‐spectrum bedrock thermal expansion displacement using the skin temperature from the ERA5 reanalysis data set. The results show that the nonseasonal variations of bedrock thermal expansion, with a range (maximum minus minimum) reaching 3 mm in some regions, can be observed by geodetic instruments and thus cannot be ignored. Moreover, the mean power of the nonseasonal variations accounts for 20% of the entire thermal expansion. Without considering the influence of the nonseasonal variations, this “noise” would remain in the original observations and contaminate related geophysical inversions.

ВИЗНАЧЕННЯ ВЕЛИЧИНИ Й ТОЧНОСТІ СТАЛОЇ ВІДДАЛЕМІРА ЕЛЕКТРОННОГО ТАХЕОМЕТРА ЗА РЕЗУЛЬТАТАМИ ПРИВ’ЯЗКИ ДО ПОДВІЙНОГО СТІННОГО ГЕОДЕЗИЧНОГО ЗНАКУ

Urgency of the research. Now manufacturers of geodetic instruments supply a variety of geodetic equipment to the market. An important place in this assortment belongs to electronic range finders. They combine in their design a goniometer, an electronic rangefinder and a processor that allows to solve various geodetic tasks based on the measurements. Target setting. To ensure reliable data on the measured distance, it is necessary to periodically determine the constant correction of the range finder of the electronic total station. This is especially true in the case of measuring distance using a reflector from an electronic total station of a different brand. Actual scientific researches and issues analysis. The method for determining the constant correction of the range finder of an electronic total station based on the results of binding to a double geodetic wall sign is described in [1]. The technology of measurements and the formula for determining the constant are shown. An unexplored parts of a common problem. In continuation of the topics given in [1], it is advisable to carry out a practical implementation of the method for determining the constant correction and establish its accuracy. The research objective. The main goal of this article is to determine the constant correction of the range finder of an electronic total station based on the data obtained from the results of binding to a double geodetic wall sign, and also to calculate its accuracy. The statement of basic materials. The approbation of the technology for determining the constant correction of the range finder of an electronic total station for the results of measurements made during binding to the double wall sign of the city polygonometry of Chernihiv is presented. The Trimble 3305 DR total station and reflector for binding to wall signs, developed at the Department of Geodesy, Cartography and Land Management of the Chernihiv Polytechnic National University, were used. As a result, a constant correction value of +22.6 mm was obtained. Formulas for calculating the mean square error of the constant correction for various options for binding to a double wall sign are derived and calculations are performed using these formulas. Conclusions. The developed technology was tested for determining the constant correction of the range finder of an electronic total station according to the measurement results obtained during binding to a double wall sign. Formulas are obtained and calculations are performed to determine the mean square error of the constant correction of the range finder of an electronic total station

Determination of vertical deviations of guide rails with different surveying techniques

Due to the diverse application areas of dimensional metrology and the demand for surveys where precision is guaranteed, the approach through geodetic surveying techniques is an alternative for large-scale metrology. In the Laboratory of Geodetic Instrumentation of the Federal University of Parana, a structure was developed for calibration of vertical Invar rods and digital leveling systems, in which this structure is composed of two parallel guide rails. The vertical deviations of these guide rails can cause deviations during the calibration processes, and consequently, affect the results of the calibration procedure. Therefore, an investigative study is proposed to determine these deviations of the guide rails by different techniques and equipment. Direct leveling methods (differential leveling using digital level and optical level), indirect methods (trigonometric leveling using total station) and electronic level were used. As results, the vertical deviations of the guide rails were obtained with submillimetre precision, regardless of technique and methodology applied. The results were evaluated using the Pearson correlation coefficient, indicating that there were no statistical differences between the calculated deviations.

New Methods and Technologies in Engineering and Geodetic Examination for Project Documentation for Residential Buildings

Engineering and geodetic examination is a part of the construction and reconstruction in major construction workprojects. Such kind of examination is implemented with the usage of special geodetic equipment or instruments such as  high-precision optical-mechanical: theodolites and levels,  high-precision optoelectronic,  precise and technical optical-mechanical and mechanical,  precise and technical with a digital device. Nowadays it’s more widespread to use navigational equipment of utilitarian purpose, which simplify this processand provides the most accurate engineering and geodetic examining. This article describes an example of how this kind of equipment can be used for engineering and geodetic examinationin order to prepare project documentation for residential buildings

RESEARCH THE APPLICATION OF TOPCON IS301 SCANNING TOTAL STATION FOR THE BUILDING OF SPACE MODELS OF ARCHITECTURAL FORMS

The article is devoted to the possibility of using an electronic total station for the construction of a 3D model of an engineering object. For this research was used a monument to Andrey Sheptytsky in Lviv. In work used total station Topcon IS301 with software Image Master. The binding to the international coordinate system is performed by the RTN GNSS receiver Stonex S900a with the field software Carlson SurvCE. The bindings of the geodetic foundations and scans are performed according to the developed precision control technique directly in the field. Creation of 3D models was performed in 3DReshaper software. Analyzed the accuracy of the obtained model. We have proposed a block diagram of laser scanning on the object by total station. It was researched that the main advantage of scanning by total station is possibility of using one device for scaning and geodetic surveying. This saves time and expense for additional geodetic instruments The average square error of the constructed model is 4.4 mm.

Geodesic methods for modeling and protection of megalopolis objects

This article presents new techniques for the use of geodetic instruments when performing work on monitoring deformation processes and protecting monuments of cultural heritage. The prevention of dangerous deformations and destruction of building structures is an extremely important task, the solution of which ensures the preservation of all construction costs. For this reason, an increased attention was given to the development of early detection methods of possible structural damage to structural elements. There are many different methods for detecting displacement. Nevertheless, little work has been devoted to the development of real time observation methods. In addition to the existing methods, a permanently operating observation station is considered. The new method is based on: 1-The use of robotic motorized total station; 2- A preliminary calculation of the measurement accuracy. The actual results of the observations are given. Besides, the technique of preserving monuments of cultural heritage, including the creation of their models based on laser scanning and survey with unmanned aerial vehicles, is shown.

Review of types of geodesic monitoring of deformations of buildings and structures under difficult engineering-geological conditions

The introductory article is a review, the article examines and analyzes the latest research and publications on this issue, namely, engineering and geodetic monitoring of deformations of buildings and structures in the modern development of the construction industry. The introductory article discusses the main types of deformed state of engineering structures, considers the problem of monitoring ground masses. The basic methods of geodetic monitoring of deformations of building structures in complex engineering geological conditions are presented. An extensive list of applications and the relevance of the development of geodetic monitoring of deformations is given. Common methods and instruments for geodetic deformation monitoring are considered: leveling, linear-angular measurements, automated geodetic systems - they are used for remote data acquisition and on-line, the implementation of laser scanning (terrestrial, air and automobile) and the process of complex shooting, using satellite navigation systems, stereophotogrammetry, the use of inclinometers in combination with geodetic instruments for monitoring engineering structures and soil masses. The advantages and disadvantages of modern geodetic monitoring methods are given.

Improving GNSS Landslide Monitoring with the Use of Low-Cost MEMS Accelerometers

Observation and monitoring of landslides and infrastructure is a very important basis for land planning, human activities, and safety. Geomatic techniques for deformation monitoring have usually involved GNSS and total station measurements or, more generally, expensive geodetic instruments, but other techniques, such as SAR (Synthetic Aperture Radar), can be efficiently applied. Using low-cost sensors could be an interesting alternative solution if the accuracy requirements can be satisfied. This paper shows the results obtained for tilt measurements using MEMS accelerometers, which were combined with mass-market GNSS sensors for monitoring five sites located on landslides. The use of a MEMS-like inclinometer requires an important calibration process to remove bias and improve the solution’s accuracy. In this paper, we explain the MEMS calibration procedure employed, with a simple and cheap solution. The results indicate that with a simple calibration, it is possible to improve measurement accuracy by one order of magnitude, reaching an angular accuracy of a few hundredths of a degree, verified by an independent technique.

National importance of surveying and ancient linear measures in the history of development of Russia

Issues of rational use of land resources are urgent contemporary problem. It is considered possible to solve it by analyzing centuries-old experience of history of land surveying, geodetic studies and mapping. The purpose of the study is to show the national importance of land surveying and ancient linear-measuring of boundary measures in the history of the state. The tasks of the article are connected with the analysis of types of geodetic surveys, linear measures and instruments during land surveying in different historical periods of development of the state. Historical and archival materials, ancient geodetic tools and maps were used as materials for the study. The study revealed that the development of surveying, the system of linear measurements and geodetic instrumentality had national importance to establish the boundaries of possessions, registration of quantity and quality of the land funds, protection of property rights, and termination of land disputes, valuation of land and establishment on the basis of equitable taxation. The main provisions of this study can add to the history of land relations in Russia and contribute to the further development and improvement of the state system of land surveying.

Hydrometeorological and gravity signals at the Argentine-German Geodetic Observatory (AGGO) in La Plata

Abstract. The Argentine-German Geodetic Observatory (AGGO) is one of the very few sites in the Southern Hemisphere equipped with comprehensive cutting-edge geodetic instrumentation. The employed observation techniques are used for a wide range of geophysical applications. The data set provides gravity time series and selected gravity models together with the hydrometeorological monitoring data of the observatory. These parameters are of great interest to the scientific community, e.g. for achieving accurate realization of terrestrial and celestial reference frames. Moreover, the availability of the hydrometeorological products is beneficial to inhabitants of the region as they allow for monitoring of environmental changes and natural hazards including extreme events. The hydrological data set is composed of time series of groundwater level, modelled and observed soil moisture content, soil temperature, and physical soil properties and aquifer properties. The meteorological time series include air temperature, humidity, pressure, wind speed, solar radiation, precipitation, and derived reference evapotranspiration. These data products are extended by gravity models of hydrological, oceanic, La Plata estuary, and atmospheric effects. The quality of the provided meteorological time series is tested via comparison to the two closest WMO (World Meteorological Organization) sites where data are available only in an inferior temporal resolution. The hydrological series are validated by comparing the respective forward-modelled gravity effects to independent gravity observations reduced up to a signal corresponding to local water storage variation. Most of the time series cover the time span between April 2016 and November 2018 with either no or only few missing data points. The data set is available at https://doi.org/10.5880/GFZ.5.4.2018.001 (Mikolaj et al., 2018).

Validation of Geodetic Seafloor Benchmark Stability Using Structure‐From‐Motion and Seafloor Pressure Data

AbstractOne commonly used method to measure and detect centimeter‐scale changes on land is structure‐from‐motion (SfM) photogrammetry, wherein sets of digital images are used to generate three‐dimensional spatial models. Subcentimeter accuracy useful for geodetic studies is achievable when these surveys are conducted on land or from the air. This method has made its way into marine environments by way of scuba, remotely operated vehicle, and autonomous underwater vehicle‐based surveys largely in the context of mapping. Repeated SfM photogrammetry surveys could be used to monitor changes in the stability of seafloor benchmarks and key sites as the interest in and need for marine geodetic measurements continues to grow. These studies require centimeter‐level accuracy or better, and some rely on accurate placement, positioning, or relocation of geodetic monuments, benchmarks, and instruments. We assessed the accuracy of the photogrammetric method for this purpose by simultaneously conducting a remotely operated vehicle‐based SfM photo survey to produce three‐dimensional spatial data, and a precise pressure survey to accurately measure height information. We found that the SfM survey agreed with the pressure survey height within its uncertainty of ±6.0 cm while using a standard, off‐the‐shelf camera adapted for underwater use. This level of relative accuracy would allow us to detect changes in geodetic benchmarks or instrumented sites between repeated surveys where large changes or the accumulation of small changes is expected within the scene over several years. We believe that centimeter‐level accuracy is obtainable with adjustments to the photogrammetry survey parameters, a higher‐resolution camera, and inclusion of additional coded targets.

Анализ классических методов учёта и определения рефракции в приземном слое атмосферы

In the instructions for modern geodetic instruments, it is recommended to introduce an amendment for the refraction, taking into account the “standard” refraction coefficient k = 0,13÷0,2. In fact, in the surface layer of the atmosphere, the refractive index can range from –6 to 6. Various classical methods of determining refraction are analyzed. Conclusions based on experimental work made by various researchers are presented. Using the results of numerous studies of various methods for determining vertical refraction, it can be concluded that all classical (static) methods do not provide a high degree of reliability to determine the refraction. An exception is the method of determining refraction at a neutral temperature stratification of the atmosphere, when the time interval is not very long. For this reason, their practical application is extremely limited. To improve the accuracy of determining refraction, it is necessary to take into account the turbulence of the atmosphere, that is, to use dynamic measurement methods that take the fluctuations of the electromagnetic wave passing through the path into account.

Юбилей первых государственных стандартов на геодезические приборы

State standards on the types, basic parameters of levels and theodolites as well as technical requirements were developed in CNIIGAiK in 1962–1963. The authors indicate the experience of developing the first State standards for geodetic instrument making, the difficulties encountered in developers. In this article the main stages of preparation of State standards, including action algorithm from technical specifications to submissions for the approval of the public service are marked step-by-step. The types of levels and theodolites, and the basic technical characteristics for each type are described. During 55 years the positive impact in the areas of production and application of standardized levels and theodolites, inter alia, streamlining the issuance of standard sizes of devices, increased production and improved their quality and technical level was revealed.

Low-cost GNSS sensors for monitoring applications

Among several instruments and techniques that can be used for monitoring purposes, GNSS technology has undergone a fast evolution and provides a large choice of solutions. Despite the best performances can be achieved by using double frequency geodetic receivers, capable to maintain high precisions even for wide-scale monitoring, in the recent years, several interesting solutions were presented in the low-cost market. In this work, a monitoring system based on a couple of low-cost GNSS receivers has been developed and tested in the field (Ponte Motta in Cavezzo - Modena, Italy). The two receivers were positioned about 50 m from each other and data were acquired at 1-Hz frequency. The position solutions were calculated both in post processing, through two different free and open-source software packages, and using an embedded RTK processor. The analysis aims to assess on one hand the capability of the system to perform the monitoring of slow displacements with the best possible precision, and, on the other hand, the performances of the real-time solutions that can be used for early warning purposes. The precisions evidenced by the tests show that such low-cost instrumentation can be used for many monitoring purposes, especially considering the cost that is about a tenth of geodetic instruments.

ENGINEERING GEODESIC PROVISION OF SPATIAL CONNECTION OF NATURAL OBJECTS

In the article the question of regulation of land relations is considered. It is noted that engineering geodesic investigations provide spatial connection of natural objects and their elements. One of the types of engineering and geodetic works is the removal of in-kind and fixing on the area of coastal strips along the reservoirs, which are carried out in order to create a favorable regime for water objects, preventing their pollution. State geodesic network-geodesic basis topographic units of all scale. Which unites in a single whole planned and high-altitude geodetic networks, created in accordance with the requirements of On approving the procedure for using the state geodetic reference System of coordinates USK-2000 in carrying out work with land management». Bit geodesic networks of thickening are the basis of topographic determinations in scale and engineering works. These works are carried out in the territories of settlements in land planning, land reclamation, land cadaster, use of water resources, etc. Bit geodetic network of thickening creates methods of polygonometry, triangulation and combination of these methods with the use of satellite navigation systems GPS. The method of marking works is chosen depending on the required accuracy of marking the point, the availability of geodetic instruments, the conditions of the area, qualification of the personnel, etc. In this case, the method of direct marking and the method of editing are distinguished. The first method consists in the direct construction of marking sizes with the given accuracy. The second method is based on the preliminary marking of the point, close to the design one, with its subsequent displacement to the design position. The method of direct marking is used, as a rule, in works of less accuracy, and the method of editing - in works that require high accuracy of marking (bridges, dams, etc.) The use of modern devices and technologies (GPS receivers, electronic total stations) allow to carry out geodetic work with greater accuracy and efficiency and convert the geodetic work to the level of new technologies.

Methods of parameters estimate of ice formations

The ice cover of the Arctic Seas is an important component of the natural conditions. It is impossible the construction and safe exploitation of the hydrotechnical structures and lines of communications on the shelf, reasonable planning and conducting of cargo and transport operations, organization of environmental protection measures without taking into account an ice cover.The information on morphometric and dynamic characteristics of ice formations, physical and mechanical ice properties, presence of icebergs and its bergy bits with various mortphometric and dynamic characteristics in the water area are necessary for an organization of successful activity on the shelf (design of hydrotechnical structures, planning of the work etc).The present article is concerned with the issues of estimation of ice formations morphometric parameters. The different remote observations methods on ice floes and icebergs are considered in the article: aerial survey, radar survey, observations using ice radar and geodetic instruments, visual observations, sonar survey of ice cover.The goal of the work is the description of peculiarities of various remote methods of observations. For each of the considered methods, the conditions of its application and peculiarities of data obtainment are considered; the list of morphometric parameters, that can be estimated, using results of corresponding observations is indicated.The mentioned algorithms and formulas are actively used during ice surveying works at the present time. The knowledge of various methods peculiarities allows to plan the composition of research works depending on their goals and tasks, determine the terms of their performance.The main merits and demerits of the considered methods of data obtainment and estimations of ice formations morphometrical parameters are phrased in the conclusion.

Fiber optic monitoring of active faults at the seafloor: I the FOCUS project

Laser reflectometry (BOTDR), commonly used for structural health monitoring (bridges, dams, etc.), will for the first time be applied to study movements of an active fault on the seafloor 25 km offshore Catania Sicily. The goal of the European funded FOCUS project (ERC Advanced Grant) is to connect a 6-km long strain cable to the EMSO seafloor observatory in 2100 m water depth. Laser observations will be calibrated by seafloor geodetic instruments and seismological stations. A long-term goal is the development of dual-use telecom cables with industry partners.

Determination of static and dynamic response of structures with geodetic methods in loading tests

The article presents the results from a static part of the load test for the Zglavje viaduct, located on the motorway A1 in Slovenia and the feasible usage of modern geodetic instruments for determination of dynamic response of a structure. Therefore, static analysis was employed for comparison of the implemented methods by which vertical displacements were measured and compared to a calculated displacement. High agreement of the results was established. In addition, experimental part of the geodetic non-contact methods to determine dynamic response of the structure was implemented on the railway bridge across the Mura river on the railway line Ormož–Hodos in Slovenia. Geodetic non-contact methods are evidently more and more applicable at determination of dynamic response for their technologic development in the area of speed and constant data capturing. Our results were provided by employing the Robotic Total Station (RTS).