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Accuracy investigation of creating orthophotomaps based on images obtained by applying Trimble-UX5 UAV

Hlotov V., Hunina A., Siejka Z.

Reports on Geodesy and Geoinformatics

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2017

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Vol. 103

106--118

EN

The main purpose of this work is to confirm the possibility of making large-scale orthophotomaps applying unmanned aerial vehicle (UAV) Trimble-UX5. A planned altitude reference of the studying territory was carried out before to the aerial surveying. The studying territory has been marked with distinctive checkpoints in the form of triangles (0.5 × 0.5 × 0.2 m). The checkpoints used to precise the accuracy of orthophotomap have been marked with similar triangles. To determine marked reference point coordinates and check-points method of GNSS in real-time kinematics (RTK) measuring has been applied. Projecting of aerial surveying has been done with the help of installed Trimble Access Aerial Imaging, having been used to run out the UX5. Aerial survey out of the Trimble UX5 UAV has been done with the help of the digital camera SONY NEX-5R from 200m and 300 m altitude. These aerial surveying data have been calculated applying special photogrammetric software Pix 4D. The orthophotomap of the surveying objects has been made with its help. To determine the precise accuracy of the got results of aerial surveying the checkpoint coordinates according to the orthophotomap have been set. The average square error has been calculated according to the set coordinates applying GNSS measurements. A-priori accuracy estimation of spatial coordinates of the studying territory using the aerial surveying data have been calculated: mx=0.11 m, my=0.15 m, mz=0.23 m in the village of Remeniv and mx=0.26 m, my=0.38 m, mz=0.43 m in the town of Vynnyky. The accuracy of determining checkpoint coordinates has been investigated using images obtained out of UAV and the average square error of the reference points. Based on comparative analysis of the got results of the accuracy estimation of the made orthophotomap it can be concluded that the value the average square error does not exceed a-priori accuracy estimation. The possibility of applying Trimble UX5 UAV for making large-scale orthophotomaps has been investigated. The aerial surveying output data using UAV can be applied for monitoring potentially dangerous for people objects, the state border controlling, checking out the plots of settlements. Thus, it is important to control the accuracy the got results. Having based on the done analysis and experimental researches it can be concluded that applying UAV gives the possibility to find data more efficiently in comparison with the land surveying methods. As the result, the Trimble UX5 UAV gives the possibility to survey built-up territories with the required accuracy for making orthophotomaps with the following scales 1: 2000, 1: 1000, 1: 500.

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Method for determining the focal length in a digital non-metric camera

Hlotov V., Hunina A., Yurkiv M.

Geomatics, Landmanagement and Landscape

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2017

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no. 3

71--81

EN

The authors analysed the methods for determining the focal length in digital cameras (DC) and proposed a method, according to which the control-measuring grid (CMG) is located vertically at a distance from the DC and a photograph of the CMG is made, then the latter (the CMG) is moved along the optical axis of the digital camera to the distance, which is fixed with a micrometre screw and, repeatedly, a series of photographs of the CMG is taken. After that, on the received digital images, the coordinates are measured on the corresponding intersections of the CMG, and subsequently, the focal length for the DC is determined. The a priori estimation of accuracy of determining the focal length for the DC by the proposed method is calculated. For approbation of the method, the focal length in the following cameras was determined: Canon EOS 350D, Canon EOS 450D, Canon EOS 5D.

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Complex geodetic research in Ukrainian Antarctic station "Academician Vernadsky" (years 2002-2005, 2013-2014)

Tretyak K., Hlotov V., Holubinka Y., Marusazh K.

Reports on Geodesy and Geoinformatics

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2016

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Vol. 100

149--163

EN

In this paper is given an information about complex geodetic research in Ukrainian Antarctic station “Academician Vernadsky”. Research were carried by Lviv polytechnic scientists, during Antarctic expeditions in years 2002 - 2005, 2013, 2014. Main objectives of the studies were: (a) study of the islands glaciers surface volumes changes in Antarctic archipelago and Antarctic Peninsula using terestrial laser scaning and digital terrestrial stereophotogrammetry survey; (b) investigation of Penola strain tectonic fault, using the results of precise GNSS observations.