Vasyl Kondratiuk, Eduard Kovalevskiy and Svitlana Ilnytska
Global satellite navigation system (GNSS) is by far the most cost-effective outdoor positioning technology currently available and used for many types of applications. In some cases a user may face difficult conditions, like restricted access to the navigation satellites due to natural or man-made phenomena. This paper presents an idea of an integrated positioning system capable of functioning under limited visibility conditions of navigation satellites. The system includes a digital antenna array, channels for converting radio navigation signals, a phase difference meter, a gyro platform with 3 gyros, an altimeter and a special calculator. With the help of mathematical modeling, the accuracy characteristics of the system are investigated by determining the coordinates of the carrier under conditions of a small number of available satellite signals.
Aleksandrs Urbahs, Sudip Das, Shravan Koundinya Vutukuru and Kristīne Carjova
Experiments and computational studies were carried out to get an understanding of the flow field around a rectangular supersonic intake with pointed cowl shape. Experiments include quantitative pressure measurements and flow visualization studies by using schlieren techniques. The effects of the presence of various cowl shapes on ramp surface have been obtained computationally at Mach 2.0. The experiments were carried out only for the pointed cowl. Schlieren Photographs were taken. Three-Dimensional simulations were made by using FLUENT at supersonic speed. The details of the experiments and computations are discussed.
Andrzej Ambrozik, Dariusz Kurczyński and Piotr Łagowski
Modern means of transport are basically powered by piston internal combustion engines. Increasingly rigorous demands are placed on IC engines in order to minimise the detrimental impact they have on the natural environment. That stimulates the development of research on piston internal combustion engines. The research involves experimental and theoretical investigations carried out using computer technologies. While being filled, the cylinder is considered to be an open thermodynamic system, in which non-stationary processes occur. To make calculations of thermodynamic parameters of the engine operating cycle, based on the comparison of cycles, it is necessary to know the mean constant value of cylinder pressure throughout this process. Because of the character of in-cylinder pressure pattern and difficulties in pressure experimental determination, in the present paper, a novel method for the determination of this quantity was presented. In the new approach, the iteration method was used. In the method developed for determining the volumetric efficiency, the following equations were employed: the law of conservation of the amount of substance, the first law of thermodynamics for open system, dependences for changes in the cylinder volume vs. the crankshaft rotation angle, and the state equation. The results of calculations performed with this method were validated by means of experimental investigations carried out for a selected engine at the engine test bench. A satisfactory congruence of computational and experimental results as regards determining the volumetric efficiency was obtained. The method for determining the volumetric efficiency presented in the paper can be used to investigate the processes taking place in the cylinder of an IC engine.
A technique is proposed to enhance the professionally important qualities of air traffic controllers at the stage of training on the basis of training group formation. The methodology is based on cluster analysis. The proposed criteria are based on the measure of the similarity of student qualities.
The research focuses on the development of an Unmanned Aircraft System. For design purposes, a rather new design method called Systems Engineering Approach is used. Development of the whole system takes much time and effort. This paper contains a concise description of the research on the preliminary development phase of Unmanned Aircraft System air vehicle. The method was first introduced by NASA and later developed by authors of books on aircraft design used for information purposes for design and are mentioned in references. The obtained results are rather realistic and promising for further design process. The method is simple and understandable, and it should be used more often to make it more steady and reliable.
This paper presents a relatively cheap helicopter assisted landing system concept. A frequency modulated continuous radar (FMCWR) is used to check an unprepared landing area for the presence of interfering objects. The spectrum processing of the converted signal is used to provide multi target resolution. The experimental research is done by using a 4.3 GHz FMCWR radar. The converted signal spectra are provided for mirror and rough surfaces, as well for multiple targets in a case of interfering object existence.
Ruta Bogdane, Yasaratne Bandara Dissanayake, Silva Andersone and Aleksandrs Bitins
In present conditions the activity of any enterprise is represented as a combination of operational processes. Each of them corresponds to relevant airline management systems. Combining two or more management systems, it is possible to obtain an integrated management system. For the effective functioning of the integrated management system, an appropriate information system should be developed. This article proposes a model of such an information system.
The aim of this article is the development of the system and methodology of complex control and evaluation of vehicle operators performance during multifunctional simulation. In order to achieve the above-stated aim it is necessary to solve the following principal tasks: to elaborate a theoretical model of differentiated evaluation of vehicle operator training degree according to different kinds of their functional performance; to develop the method of the differential evaluation of crew performance on full-scale aviation simulators with due consideration of the probabilistic approach on the basis of statistical processing of the data of recorded flight information. The offered theoretical model of the differential evaluation of operator performance and the methodology of standards determination developed on its basis represent a new approach to the creation of automated systems for the objective evaluation of the trainees’ qualification degree. The elaborated system of differential evaluation standards ensures a high degree of objectiveness when evaluating the degree of the vehicle operator qualification and makes it possible to carry out a comparative analysis of the operators’ qualification.
Aircraft crew training corresponds to the interactive learning models of sensorimotor skill acquisition, and the dynamics of skill acquirement can be approximated by the exponential trend. A model of 5-grade assessment of separate exercises is offered. It helps to calculate a resulting evaluation, in accordance with which the progress level of a discrete exercise is evaluated. Such an evaluation forms one of the points for the analytical construction of a learning curve using the Gaussian method. Possible applications of the learning curve are covered.