Current research on Unmanned Aerial Vehicles (UAVs) shows a lot of interest in autonomous UAV navigation. This interest is mainly driven by the necessity to meet the rules and restrictions for small UAV flights that are issued by various international and national legal organizations. In order to lower these restrictions, new levels of automation and flight safety must be reached. In this paper, a new method for ground obstacle avoidance derived by using UAV navigation based on the Dubins paths algorithm is presented. The accuracy of the proposed method has been tested, and research results have been obtained by using Software-in-the-Loop (SITL) simulation and real UAV flights, with the measurements done with a low cost Global Navigation Satellite System (GNSS) sensor. All tests were carried out in a three-dimensional space, but the height accuracy was not assessed. The GNSS navigation data for the ground obstacle avoidance algorithm is evaluated statistically.

This paper presents analyzed questions of the safety of the information transferred by the radio connection link of the Polish UAV project “Aircraft for monitoring” SAMONIT. This safety is especially important for the design and use of unmanned aerial vehicles (UAV). This paper also presents the structure of the SAMONIT communication system, security threats to the radio connection system, and possible measures to ensure secure information. Santrauka Straipsnyje nagrinejami Lenkijos bepiločiu orlaiviu projekto SAMONIT (monitoringo lektuvas) radijo ryšiu perduodamos informacijos saugumo klausimai. Ypač svarbi yra radijo ryšiu perduodamos informacijos apsauga kuriant bepiločius orlaivius (BO) ir kitas nuotolinio valdymo transporto priemones. Straipsnyje pateikiama SAMONIT ryšiu sistemos struktūra, galimos gresmes informacijos perdavimui, saugumui bei integralumui; taip pat radijo ryšio sistemos apsaugos būdai bei priemones.

ABSTRACT:Implementation of Unmanned Aerial Vehicles for civilian applications is rapidly increasing. Technologies which were expensive and available only for military use have recently spread on civilian market. There is a vast number of low cost open source components and systems for implementation on UAVs available. Using of low cost hobby and open source components ensures considerable decrease of UAV price, though in some cases compromising its reliability. In Space Science and Technology Institute (SSTI) in collaboration with Vilnius Gediminas Technical University (VGTU) researches have been performed in field of constructing and implementation of small UAVs composed of low cost open source components (and own developments). Most obvious and simple implementation of such UAVs -orthophoto imaging with data download and processing after the flight.

This article examines and shows mathematical results of classical algorithm, which is used for small Unmanned Aerial Vehicle (UAV) navigation. The research is done with mathematical UAV model, which eliminates aerodynamics while the chosen flight path is followed by using vector field method. Lots of attention is dedicated to show possible flight path error values with representation of modelled flight path trajectories and deviations from the flight mission path. All of the modelled flight missions are done in two-dimensional space and all of the collected data with flight path error values are evaluated statistically. The most possible theoretical flight path error values are found and the general flight path error tendencies are predicted.

The paper presents the application of wireless sensor networks in aviation for measuring and transferring flight parameters. IEEE 802.15.4 standard ZigBee of low price, which operates in the low range of the ISM frequency band, was chosen. Experiments were performed during free flight. Evaluation of measurement results using Kalman filtering algorithm is provided. Ill. 6, bibl. 10, tabl. 1 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.111.5.353