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Study of karst manifestations in Solotvyno based on aerial photography from a UAV

Hlotov Volodymyr, Shylo Yevhenii, Yatskivskyi Yaroslav, Kablak Nataliya, Nychvyd Mariya

Reports on Geodesy and Geoinformatics

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2023

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Vol. 115

27--34

EN

This article is devoted to the study of surface karst manifestations on the territory of inactive salt mines of Solotvyno, Transcarpathian region, Ukraine. The historical development of the salt mine from the moment of the creation of the first mine (the end of the 18th century) to the present is considered. Based on the results of previously published studies, monitoring of karst manifestations from 2010 to 2020 was implemented. The last stage of monitoring in 2021 was the aerial survey of the territory obtained by the Arrow UAV using the Sony QX1 camera. Pix4Dmapper software was used for image processing. The aim of the work is to estimate the scale of destructive geological processes by the method of photogrammetry. During the execution of the work, the methods of processing materials of aerial photography, analysis of developments in the direction of photogrammetry were applied. As a result of the study, the volume-planar characteristics of karst formations on the territory of Solotvyno were calculated using the photogrammetry method. This scientific work is relevant for assessing the scale of the development of degenerative geological processes on the territory of Ukraine, in particular within the Transcarpathian region. The practical significance of the obtained results lies in their application in order to ensure environmental monitoring. The results of the study can be used to predict the impact on economic and infrastructure objects, followed by the development of a plan of specific actions for prevention, localization and work with the consequences of man-made processes in the adjacent territory.

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Planning measurement campaigns for precise GNSS positioning in various observation conditions

Siejka Zbigniew, Hlotov Volodymyr, Fys Mykhailo

Geomatics, Landmanagement and Landscape

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2022

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no. 3

75--92

EN

Currently, GNSS (Global Navigation Satellite System) positioning systems are becoming widely used not only in geodesy, but in broad positioning in very many areas of the economy and society. The growing popularity of GNSS, especially recent, is related to their significantly increasing availability and a reduction of measurement time to a minimum, while maintaining high positioning accuracy. High positioning accuracy is ensured, among other things, by applications that allow planning observation sessions so that measurement is taken at the best time windows. It is the moment when the impact of measurement errors due to the constellation of observed satellites is the smallest. The following paper presents an example of the use of such an application and its benefits for planning GNSS observations. This type of research is particularly important for urban areas, where conditions for receiving GNSS signals are particularly difficult. Increasing the number of observable satellites and simultaneously minimizing the value of the Position Dilution of Precision (PDOP) parameter allows obtaining position coordinates (3D) with high accuracy from the point of view of relevance to GNSS measurements. The paper demonstrates the fundamental significance of satellite constellation geometry for GNSS applications requiring high accuracy position determinations, for which correct planning of a measurement campaign is crucial. It avoids this way large errors or conditions that render the observations of a particular GNSS measurement method impossible.

PL

Aktualnie, satelitarne systemy pozycjonowania GNSS (Global Navigation Satellite System) znajdują coraz szersze zastosowania nie tylko w geodezji, ale w szeroko pojętym pozycjonowaniu w bardzo wielu dziedzinach gospodarki i życia społecznego. Coraz większa popularność GNSS wynika z faktu, że szczególnie w ostatnich latach istotnie zwiększyła się ich dostępność oraz skrócił do minimum czas pomiaru, zapewniając jednocześnie wysoką dokładność pozycjonowania. Wysoką dokładność pozycjonowania zapewniają między innymi aplikacje, umożliwiające odpowiednie zaplanowanie sesji obserwacyjnej pod względem znalezienia najlepszego okna czasowego do wykonania pomiaru. Wówczas wpływ błędów pomiarowych wynikający z konstelacji obserwowanych satelitów jest najmniejszy. W niniejszej pracy przedstawiono przykład zastosowania takiej aplikacji oraz korzyści wynikające z jej wykorzystania do planowania obserwacji GNSS. Tego typu badania są szczególnie ważne w terenach zurbanizowanych, które charakteryzują trudnymi warunkami odbioru sygnałów GNSS. Zwiększając liczbę możliwych do zaobserwowania satelitów i jednocześnie minimalizując wartość parametru PDOP (Position Dilusion of Precision) rozwiązujemy problemem umożliwiający uzyskanie współrzędnych pozycji (3D) z wysoką dokładnością z punktu widzenia znaczenia dla pomiarów GNSS. W pracy wykazano fundamentalne znaczenie wpływu geometrii konstelacji satelitów dla aplikacji GNSS wymagających wysokich dokładności wyznaczeń pozycji, dla których poprawne zaplanowanie kampanii pomiarowej jest bardzo istotne. Unika się w ten sposób sytuacji pojawienia się dużych błędów lub w ogóle braku warunków obserwacyjnych dla zastosowani danej metody pomiarów GNSS.

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Determining of correlation relationship between roll, pitch, and yaw for UAVs

Hlotov Volodymyr, Hunina Alla, Yurkiv Mariana, Siejka Zbigniew

Reports on Geodesy and Geoinformatics

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2019

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Vol. 107

13--18

EN

Currently, UAVs are intensively being introduced into topographic-photogrammetric production for topographic digital aerial photography and laser scanning. These technologies have a number of advantages: they don’t require specially prepared platforms and launchers, they are relatively inexpensive unlike large aircrafts, and they are safe. However, there are still many unsolved problems for ultralight UAVs, especially when the aerial photography is made. As you know, the requirements for the implementation of the aerial survey process are quite stringent, first of all, for horizontal flight: the angles of inclination must be within 3–5 degrees, since exceeding these tolerances significantly affects the accuracy for determining the spatial coordinates of objects. Therefore, there was an idea to conduct researches of dependences between the pitch α, roll ω and yaw κ. For this purpose, 100 images obtained from aircraft-type UAV ‘Arrow’ developed and created by specialists from Lviv Polytechnic National University and ‘Abris’ were used. As a result of the study, the multiple correlation coefficient and the parameters of the linear regression equation for the angular elements of the exterior orientation of digital images were calculated. In addition, statistical quality evaluations for the obtained regression model were carried out. Analysis of the received data allows to assert that angular elements of exterior orientation are correlated with each other. Therefore, in the further imaging materials, processing it becomes possible to make compensation of this fact and to improve calculation accuracy of spatial coordinates of points.

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Study of the method for focal length determination in digital cameras

Hlotov Volodymyr, Hunina Alla

Geomatics, Landmanagement and Landscape

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2019

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no. 4

145--154

EN

The authors analysed the methods for determining the focal length in digital cameras (DC) and proposed a method, the implementation of which is to survey the correct triangular metal prism from the left and right points of the basis. Next, on the stereo pair of digital images obtained from the surveying, the corresponding coordinates of the points on the near and far edges of the prism are measured, and the focal length of the non-metric DC is determined. To test the method, the focal length of the Sony ILCE-7R and Canon EOS 450D cameras was determined. In order to establish the precision parameters of the method, the following parameters were taken into account: determining the accuracy of measurment on the basis of surveying, the accuracy of measuring the heights, the accuracy of calculation of the longitudinal parallax, the accuracy of calculating the difference between the parallaxes.

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Constructing the 3D-model of a glacier part on the Galindez Island

Hlotov Volodymyr, Biala Myroslava

Geomatics, Landmanagement and Landscape

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2019

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no. 2

55--62

EN

The publication is based on the research carried out at the Ukrainian Polar Station “Academic Vernadsky”, located in the Antarctic region at the Galindez Island. The article establishes relationships between global climate change and changes occurring in the area of Galindez Island based on 3D models of the glacier surface. The article has two parts. The first one reviews software products (AutoCAD, ArcGIS, SketchUp, Digitals) used for three-dimensional surface modeling. We analyze their characteristics, and emphasize the advantages and disadvantages of each program for the purpose of terrestrial 3D modeling. In the second, experimental part of the research, we present 3D models of the glacier surface constructed using various software products. The result of the research presents the obtained model of Galindez Island including all relevant textures and buildings.