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.

SummaryThe 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. Keywordsfocal length • digital non-metric camera

The main purpose of this work is to confirm the possibility of making largescale 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 work aims to analyze and study the possibilities of using “Cetus” unmanned aerial vehicle (UAV) for performing topographic aerial surveys. The authors developed and tested aircraft-type UAV for topographic aerial photography. The studies were conducted on a specialized landfill, at which there is an appropriate number of situational points whose coordinates are determined with high accuracy. These points were used as both reference and control points. The obtained UAV aerial survey materials were subjected to a phototriangulation process to determine the orientation elements and to analyze, first and foremost, the angular orientation elements. The surveying was carried out on a mountainous territory, where the spatial coordinates of 37 situational points were determined by the method of ground-based GPS survey with an average accuracy of up to 0.05 m. These points were used as reference and control points. Aerial photography was performed in such a way that the scale of the images was as uniform as possible. The design solutions implemented in the Cetus UAV provide all the possibilities to perform aerial surveys of territories in strict compliance with the projected flight parameters. UAV equipment provides the necessary real-time correction of the position of the aerial camera. At the same time the optimum straightness of routes, stability of scales and mutual overlapping of pictures is reached. Regarding the accuracy of obtaining the spatial coordinates of the points of terrain objects, using “Cetus” UAV surveys, plans can even be made on a scale of even 1: 1000. As a result of the creation of the UAV “Cetus”, it became possible to perform the topographic aerial survey of the territories and to create large-scale orthophotos that fully meet the instructions. As a result of testing the “Cetus” UAV, it can be used in production processes when drawing up topographic plans for a large-scale series: 1: 1000 – 1: 5000, which will significantly save the cost of performing topographic work.

Aim.To develop an UAV for topographical aerial surveying goals, to explore its features, and comply with assigned tasks. Methodology. Scientists of the Institute of Geodesy in National University Lviv Polytechnic and manufacturers of Abris Design Group consistently designed and studied several models of UAVs, in order to create a perfect model, to make it possible to organize aerial surveying for topographical purposes. As a result of previous experimental work, technical requirements for the creation of UAVs were defined. It is for these requirements the latest model UAV Arrow was constructed. To test the model of the aircraft, a technological scheme of testing has been developed in order to identify design deficiencies and obtain appropriate certified aerial photos and further to create large-scale topographical plans and orthophotomaps. Results. As a result of pilot works with the use of UAV Arrow, possible problems related to the UAV launch were identified and means to eliminate them were given. As a result of the testing aerial surveying from the Arrow UAV, 132 images from 7 routes were obtained. In order to assess the accuracy of determining the coordinates of points of the locality, 57 points were marked. The coordinates of control points were determined during the execution of the horizontal and vertical tie-in by GPS-receivers Trimble R7 in RTK mode. After the creation of orthophotomaps, in the Digitals software package, using these materials the coordinates of the above-mentioned control points were measured and the MSE were founded. MSE for planned coordinates were: m x = 0.19 m, m y = 0.11 m, which confirms the ability to create plans at a scale of 1:2000. Scientific novelty. The UAV Arrow was designed and investigated, which application allowed performing aerial surveying and processing of large-scale orthophotomaps with the required accuracy. Practical significance. The possibility of using materials obtained from the results of aerial surveying with UAV Arrow to process orthophotomaps at a scale of 1:2000 was proven.