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This paper provides a comprehensive view of the issues in the field of servomechanisms of unmanned aircraft, which are used in the Department of Avionics for both education and research purposes. This contribution will describe the methodology and individual measuring devices, facilitating the control of prescribed parameters with parameters measured in real conditions. As some manufacturers deliberately exaggerate the data of their products to compete with other manufacturers, it is important to have a proven and reliable method for the evaluation of these parameters. The last part provided the results of control measurements of the selected servomechanism.

In the area of successful landing and guidance of the aircraft on the route, flight safety is perceived as the highest rate of observation of all operational-control functions of the aircraft. The given functions of the aircraft are observable and identifiable by the systems and cognitive perceptions of the pilot. Situational control of the aircraft on the route with the identification of the danger, into which the pilot can get is perceived as an exact element of failure. If the pilot enters such a situation, apriori solutions are offered to him/her by the aircraft information system. The character and emergency solution in the highest criticism of the failure of aircraft systems is the controlled landing in the local safety corridor when guiding the aircraft on the selected route. The aim of the article is the theory of the solution for the introduction of an assistance element in small aircraft with a description of the solution of autonomous choice of geolocation in a defined local environment. By a heuristic experiment in the article, let’s prove the methods of selection of geographical areas for landing an aircraft with the possibility of introduction into the aircraft information system. The article presents the methodology of creation autonomous assistance system, based on the measurement of detection areas for landing with the collection of data from the GIS system. This system can assist in pilot training and real flights for small aircraft without difficulty. The effectiveness of such system and the parameterization of its data were shown and proved. The developed models may be further used for creation an autonomous selection system in the event of accidental aircraft failures

At present, one of the most frequently discussed topics, not only at international conferences, but also within the EU, is the issue of airport financing, as well as the thresholds at which airports can cover their operational costs and when the need for support is justified. The Strategic Airport Development Plan and the Airport Business Plan are one of the most important support documents for making the right decision for airport financing and prepare the project for operational and investment aid. For preparing these documents is significant the category of the airport, that means the number of passengers. This paper is focused on the methodology how can be predict the number of passengers from previous data by used the time series method.

We consider a conceptual approach for the applicability of airborne weather radar for the sea ice/water discrimination and estimation of the sea ice age. The sea ice/water discrimination method suited for the airborne weather radar utilization is based on finding the minimum statistical distance of the measured normalized radar cross sections within a wide azimuth sector to the geophysical model functions of the sea ice and water, respectively. The sea ice age classification is based on the comparison of the normalized radar cross section value at a given incidence angle to the lower normalized radar cross section boundaries for the first-, second-, and multi-year ice. Implementation of the proposed methodology is considered for the C-band airborne weather radar operated in the ground mapping mode as a scatterometer scanning in a wide azimuth sector up to ±100°. We show explicitly that the proposed approach provides the enhancement of the conventional airborne weather radar functionality for the sea ice/water discrimination and sea ice age estimation either using stand-alone or joint measurements.

This paper deals with the Unmanned Aircraft Vehicle (UAV) flight phases dynamics simulation. It predicts the accuracy of the UAV flight using the output graphs. The monitoring of the main flight phases (take-off, en-route, landing) is carried out using instruments, UAV standard procedures and rules established by the applicable aviation standards for the method of Unmanned Aircraft Vehicle operation. The fundamental peculiarity of flight and technical analysis is based on a gradual qualitative change in the movement of a known flying vehicle, where its operating systems and its management and control rules are gradually changed and transformed in accordance with technical, operational and legislative conditions which means the transfer of flight and technical analysis from the area of mathematical-mechanical precise flight tracking and the sophistication of its operation in a mountainous environment.

The article analyzes the interaction of electromagnetic waves of a radio navigation signal with the relief of the earth’s surface and its electrical properties. As a result of this interaction, such physical phenomena are created that have a significant negative effect on the accuracy of the ADF’s alignment of the NDB signal. One of the two objectives of the article is to acquaint the aviation public with the physical nature of this natural phenomenon in terms of flight safety, which occurs to a large extent especially in mountainous countries, including Slovakia. The second goal of the article is to inform the professionals in the field about this phenomenon in terms of its nature as a physical law, in order to find ways to increase the accuracy of measurement of this navigation system.

This article presents a novel concept for a highly accurate and simple two-port vector signal analyzer. A current phase ratio measurement method is defined for one independent external signal with a restriction of the measuring range ±90 or ±180°. The article presents a new way of phase ratio evaluation of two independent external signals with precise phase determination in a wide range from 0° to 360°. The new functional blocks of the analyzer circuit element act as a four-position radio frequency (RF) switcher and an algorithm for phase determination is presented. Practical application and verification of the results achieved are demonstrated by measuring the phase directional radiation pattern of a complex object such as an aircraft fuselage.

The strict safety requirements of air transport for nonstandard placement of electronic onboard systems require an innovative approach to the experimental verification of the placement of these devices. Particular attention is required to the location of these electronic devices’ antenna systems on the fuselage. A prerequisite for determining the location of the antenna and verifying its radiation is a thorough knowledge of the radio communication transmission of onboard electronic systems in cooperation with terrestrial or satellite systems. From this point of view, this article focuses on an innovative method of verifying the spherical radiation characteristics of the antenna of an onboard rescue system emergency locator transmitter (ELT) to assess its communication link with the Cospas-Sarsat satellite system. The measurement is performed on a small sports two-seater aircraft with an antenna placed in an unusual place in the aircraft’s cabin, between the seats. It was impossible to use a suitable nonreflective attenuation chamber for the measurement, so we present a method and procedure for this type of measurement in the open space of an airport. The achieved results prove the plausibility and reproducibility of the measurement. Furthermore, combining several polar radiation characteristics makes it possible to obtain an idea, even if only a part, of the spatial (spherical) radiation characteristic. This article presents a simple method of measuring the characteristics of aircraft antennas when it is not possible to use a suitable professional nonreflective attenuation chamber for measurements for various reasons. This method can also be used on other larger means of transport or other objects that experience the same problem.

Lately, the UAV has repeatedly been the main issue of many international scientific conferences worldwide and many researchers or professionals are discussing the safety and security of UAVs versus air transport. The state authorities, whether civilian or military, have to find the most appropriate form of solution to create the national legislation that reflects the changes in European legislation after establishing the framework within 2018-2019. At the same time, it is necessary to respond to the ever-growing progress in the production of UAV technologies and their impact on air transport market. However, the most important is the safety of the UAV flights. Which in Slovakia means the ability to safely overcome obstacles, which is the subject of this paper. The paper focuses on the simulation and analysis of UAV vertical flight, while avoiding mountain obstacles in mountain orographic terrain. The result of the research is a method of a safe flight execution in terms of its technical execution while respecting the legislative conditions valid in the territory of the Slovak Republic.

The aircraft avionics modernization process often requires optimization of the aircraft itself. Scale models of aircraft and their antennas are frequently used to solve this problem. Here we present interesting properties of the resonant antennas, which were discovered serendipitously during the measurement process of some microwave antennas’ models as part of an aircraft modernization project. Aircraft microwave antennas are often designed as non-symmetric flat microwave antennas. Due to their thin, low and longitudinally elongated outer profile, they are also called tail antennas. An analysis of the resonant properties of non-symmetric antennas was performed in the band from 1 GHz to 4 GHz. The length of the antenna models ranged from 2 cm to 7 cm. The width of the antennas, together with the thickness of the strip, was always a constant parameter for one measured set of six antennas. In the measurement and subsequent analysis, attention was focused on the first-series resonant frequency (λ/4) of each antenna. During the evaluation of the resonance parameters, the flat microwave antenna models showed specific resonant properties different from those of conventional cylindrical microwave antennas. This article aims to inform professionals about these unknown specific properties of non-symmetrical antennas. The results of experimental measurements are analyzed theoretically and then visually compared using graphs so that the reader can more easily understand the properties observed. These surprising observations open up some new possibilities for the design, implementation, and use of flat microwave antennas, as found in modern aircraft, automobiles, etc.

Following the mission science plan of EPS/Metop-SG C-band scatterometer for 2023&ndash, 2044, we consider the potential application of the sea ice/water discrimination method based on the minimum statistical distance of the measured normalized radar cross sections (NRCS) to the geophysical model functions (GMF) of the sea ice and water, respectively. The application of the method is considered for the classical spacecraft scatterometer geometry with three fixed fan-beam antennas and the hypothetical prospective scatterometer geometry with the five fixed fan-beam antennas. Joint vertical (VV) and horizontal (HH) transmit and receive polarization are considered for the spaceborne scatterometer geometries. We show explicitly that the hypothetical five fixed fan-beam antenna geometry combined with the dual VV and HH polarization for all antennas provides better estimates of the sea wind speed and direction as well as sea ice/water discrimination during single spacecraft pass. The sea ice/water discrimination algorithms developed for each scatterometer geometry and dual VV/HH polarization are presented. The obtained results can be used to optimize the design of new spaceborne scatterometers and will be beneficial to the forthcoming satellite missions.

The paper deals with the problem of ultra-light and light aircraft structural health monitoring. The phenomenological basis and engineering decisions for methods to monitor accumulated fatigue damage and to register overstress of aircraft principal structural elements have been shown. The proposed fatigue indicator is lightweight and autonomous; the output information of the indicator reflects the inhering feature of the fatigue damage – appearance and growth of surface extrusions and intrusions. The overstress indicator simplicity and correctness of the information is provided by “fuse” principle of the design.

In some cases, nadiral wind retrieval algorithms are not applicable for wind measurements due to the specificity of a radar instrument measuring geometry or its mounting on aircraft, and so off-nadir backscattering measurements can only be performed. In this paper, a method for off-nadir wind retrieval over the sea based on the sea-surface backscattering measurements with the Airborne Precipitation Radar-2 or similar radar measuring geometry has been proposed. The study is based on a theory of the quasi-specular microwave backscattering from the sea surface. An anisotropic water surface approach is considered. The wind vector is retrieved from the system of equations for measured normalized radar cross sections (NRCS) by using the relationships between the speed of the sea-surface wind and the standard deviations of the sea-surface slopes along the up- and cross-wind directions. A wind vector recovery with the cross-track scanning measurement geometry has been simulated. The maximum errors of the ...

The main focus of this paper is aimed at the possibilities of mutual influence of ground and airborne weather surveillance radars (WSR) from the operation in approximately same frequency band viewpoint. Specialized technical and legal details of the problem are being discussed in the paper. The problem arose during air transport safety assessment in the vicinity of airports under unfavourable meteorological conditions, when a large number of weather radars of the same type are being used at a relatively small area. This is the consequence of the fact that each aircraft is equipped with weather radar working at frequency band 9.3 ÷ 9.5GHz. From the security viewpoint, these radars have irreplaceable position in informing the pilot of the meteorological situation ahead of the flying aircraft. Popularity of these weather radars with producers and operators on board the aircraft is also based on their small dimensions, relatively simple design, quality and reliability of processing and displaying of meteorological situation for the pilot. The need to be informed of the meteorological situation in the vicinity of the airport is also necessary for the ATCs. Besides, it is the interest of radar network operators to use their meteorological information for commercial purposes. Increasing the number of these weather radars working side by side in a limited space at the frequency band only 200Hz wide inspires justifiable questions connected with electromagnetic compatibility and possible mutual interference.

Presented paper concentrates on accidentally identified, specific method of mechanical vibration demodulation, radiated high-frequency signal of aircraft communication antenna, located directly on the aircraft. It describes the structure and solution of the designed laboratory workplace at which it is possible to evoke mechanical vibration demodulation as a specific phenomenon. The aim is to analyze possible physical electric characteristics of antenna as a source of mechanical vibration on “Monopole“ type of antenna. Next, transfer amplitude frequency characteristics of the antenna, as a mechanical vibration demodulator, are analyzed. As this is a basic research of this accidentally identified phenomenon, an observation method of experiment results is used to find out the analogies by the form of their comparison with a classical amplitude demodulator. The results show that if the mechanic influence of artificial ground is suppressed, the transfer amplitude frequency characteristics of such demodulated signal has minimal distortion in frequency range 200Hz to 3.5kHz. The paper presents brief summary of measured basic values on the base of which obtained results are analyzed and brief conclusions of observed phenomenon are defined. They are the first outputs of the phenomenon observations on the base of which it can be concluded that it is reasonable to deal with this problem. At the same time this is not just the antenna characteristics analysis but also the analysis of mechanical oscillations of the antenna from the viewpoint of its more secure fixing at the aircraft fuselage. Because the concurrent influence of two kinds of vibrations, primary – as a result of aerodynamic circumfluence of antenna during the flight in collaboration with the secondary – as a result of its radiation, places higher requirements on its mechanical fixation. Presented facts mean the increase of air traffic operation.

Each vehicle antenna has a variety of electrical and mechanical properties that characterize it. Each one of the considered series of features evaluates the antennas from a different point of view. The electrical properties of antennas are characterized by its various energy, impedance and radiation parameters. The radiation parameters of the antenna can be objectively assessed according to the shape of its radiation - directional characteristics. The shape of the directional characteristic of the antenna is influenced by a number of interrelations between its electrical and mechanical properties. The best known relationship that affects the shape of the directional characteristic of the antenna is the ratio between its mechanical parameter - the antenna length “l” and the electrical parameter - the wavelength “λ” of the operating frequency. In the theory of antennas, it is a known ratio “l / λ”, which determines the shape of the directional characteristic of the antenna. This ratio, which shapes the electric current distribution on the antenna, can be evaluated or simulated relatively simply (but not exactly), but in practice it is very difficult (almost impossible) to measure it. The article deals with a specific approach to objective practical measurement of electric current distribution on a linear antenna in the VHF frequency band.

This article describes the design and implementation of a low-profile sinuous slot antenna, intended for ultra-wideband (UWB) sensor networks, which can be produced on one conductive layer. The article explains the design and optimization of the sinuous slot antenna and its modifications, including its sinusoidal curve shape. Other modifications were aimed at optimizing the antenna feeding. Desirable properties of the designed and implemented antenna modifications were verified both by simulation and empirically. Experimental measurements of the antenna&rsquo, s properties were carried out using a vector network analyzer in an anechoic chamber and also by a pulsed UWB radar in the frequency range from 0.1 to 6 GHz. The low-profile antennas were implemented on a Rogers RO3206 substrate.

In our laboratory, we developed a simple estimation of the wall thickness by the UWB (Ultra Wide-Band) radar system. The described technique measures the wall thickness in the two steps. The first step is a measurement of the wall relative permittivity. The second step is a reflections localization and estimation of the wall thickness. The borders of the wall could be detected by the envelope of the received signals. The described technique calculates the signal envelope by the Hilbert transform. Moreover, the relative permittivity of the wall is estimated by the technique developed in our department as well. The effective relative permittivity is calculated from the frequency dependency of relative permittivity.

The paper focuses on the new trend of increasing the accuracy of low altitudes measurement by frequency-modulated continuous-wave (FMCW) radio altimeters. The method of increasing the altitude measurement accuracy has been realized in a form of a frequency deviation increase with the help of the carrier frequency increase. In this way, the height measurement precision has been established at the value of &plusmn, 0.75 m. Modern digital processing of a differential frequency cannot increase the accuracy limitation considerably. It can be seen that further increase of the height measurement precision is possible through the method of innovatory processing of so-called height pulses. This paper thoroughly analyzes the laws of height pulse shaping from the differential frequency presented by the number that represents the information about the measured altitude for this purpose. This paper presents the results of the laboratory experimental altitude measurement with the use of a so-called double-channel method. The application of obtained results could contribute to the increase of air traffic safety, mainly in the phase of the aircraft approaching for landing and landing itself.

In accordance with the future aims, when these aerial transport objects (ATO) could fly in a selected corridor, it is also important to simulate states based on the status monitoring of dangerous situated in the complex environmental condition of the Slovak Republic (SR). With due regard to the orography of the territory, it is important to locate residual areas, where there is no possibility of their telemetric control. In the given issue, however, it is also necessary to take into account the legal framework representing a supplementary control function of maintaining flight safety of air traffic control in compliance with the ATM policies. The set-up of functional efficiency of controlling the flight of such an ATO in a complex area must be stable. In the article, stability is presented by error analysis at given lateral deviations after the ATO has switched into autonomous flight mode. Due to the errors caused by the external environment, the ATO must perform a precise flight into the area and achieve the success of the flight mission. For example, it may involve a flight into mountain territories, where it is important to secure the patient s status or the person under threat. The laboriousness of solution of such flights in a limited mountain terrain is divided into files of intelligent autonomous ports (Sky Control Object Power Environment – SCOPE). The task is to cover the residual areas for minimizing the time of rescuing persons present in the active corridors taking into account the probability of environmental change. Analysis in the article is the fundamental navigational task of flying in the corridor itself in a precise navigation mode of autonomous flight, while presuming the possibility of error occurrence of the Navigation Ergatic Complex (NEC), the element of which are made up of an inertial navigation system, Doppler sensor of speed and drift angle carried on an unmanned aerial vehicle.

The article is dealing with the theory of Crossed Field Antenna -CFA. This type was patented recently and sees its practical application particularly in area of long and medium waves. A brief theoretical analysis of the principle of radiation of this new type of antenna, which is not wave dependent to its physical dimensions, is present in this article. The independence on waves of the current CFA s enables substantial reduction of mechanical dimensions for medium wave (MW) antennas. Thereby, the dimensions of MW antennas reduces from hundreds of meters to structures measuring only several meters without affecting their electrical parameters -like power, impedance and radiation. The article is presenting a proposal and an analysis regarding the potentials in using CFA in high frequency (HF) and very high frequency (VHF) frequency bands. From this point of view, reducing the size of the airborne communication antennas is among the long-term goals of the authors research conducted at the educational institute.

The paper focuses on the area of economic evaluation and reliability of ergatic base complex operator. The estimation of operation quality, mainly with in-built complex systems, is evaluated with the use of various methods. The selected method presumes the use of efficiency indicator of performed tests in order to prove implementation tests reliability of new complex systems into ergatic base complex. The outputs create numeral characteristics according to which it is possible to estimate the level of conformity of costs on their operation itself. Therefore, the optimization of financial costs on maintaining the reliability of the above mentioned systems with the assumption of estimated level of the optimization of unexpected costs for the operator, e.g. of airport base system, is the decisive parameter [1]. The paper describes the possibilities of MATLAB environment applicability while observing effective use of resources to sustain high reliability of airport base system and its mutual relationship with current complex systems.

Aviation ergatic systems models are used in the design of concrete aviation systems and their adequacy is evaluated in the process of their design. Generally, a concrete ergatic process is realised with the help of simulation technology. Computer systems of recent and perspective flight simulators contain the architectures of hybrid information systems. Due to this, analogue as well as discrete methods of estimation of ergatic systems parametric sensitivity do not lose their practical importance.

Insufficiency in showing errors in aviation ergatic system is understood to be a situation when there is no available information about the system or some of the board information is unreliable. With the use of the method of automatic diagnosis it is possible to analyse the symptoms of analytical redundancy. Residual differences, i.e. residuents, which are the final value expression of the consequences (effects) of function observation, which are measured on obtained mathematical model, are the keystones of this method. The content of the mathematical model application contains generator of residuents, i.e. signals, which carry the information about the incorrectness (errors) and aviation ergatic system (AES) failures.

The Technical Note presents the possibility of applying the classical onboard aviation radar altimeter in the function of a simple anticollision system. Currently, classical radar altimeter offers two important pieces of information for pilots: actual flight altitude and aircraft descent at the level of decision making. The goal here is to draw attention to the innovative technique of using the radar altimeter to generate further crucial information for the pilot of a helicopter or small aircraft for predicting the threat of collision with the terrain. This new technique is based on the evaluation of the Doppler frequency in the differential signal of the radar altimeter. The theoretical assumptions have been verified by simulation and experiment.

Software simulation environments are used in design of an aircraft and its systems providing engineers with valuable insight into the behaviour of the proposed systems before they are executed. One of these software tools is MATLAB - Simulink. This simulation software environment can also be used in the design of aircraft fuel systems, for example, in detection of fuel ow changes in the fuel system of an aircraft during the flight of the aircraft by environmental impact.

Recent aviation technologies are characterized by high flight security guaranteed by wide information basis, which decreases error tolerance range on a large scale. It is tolerant towards flight parameters entropy, it is obtained by using cybernetic systems, which shape human — operator — control abilities in more and more urgent way. The existence of mutuality of intolerance needs requires narrow information connection between the machine (aircraft) and the person (its operator). In the presented paper the intolerance is perceived as an ergatic effect, the principle of which is based on machine artificial intelligence and human natural intelligence. Learning is the common name of presented intellects, i.e. perception of error existence, their recognition and compensation. Locomotion organs (most frequently arms and legs) present the disposition of the human — operator for entering control process, the dynamics and amplitude relevance are the result of the transformation of information flows worked out by his intellect. Degree and quality of informative evaluation of the situation (in time) of mutuality of the position (aircraft) and required position of the control is decided by the operator. In the paper, the adequacy of visible movement is called a skill. The development of the operator pilot skills is based on many factors. His improvement is a subject of physical laws, mathematical model of which is presented in the paper and explained by an example.