Lidé na fakultě
Ing. Tereza Topková, Ph.D.

2024, Journal of Air Transport Management, 119, ISSN 0969-6997

The future development of aeronautical navigation foresees an infrastructure rationalization of radionavigation aids with the aim of maintaining only the Minimum Operational Network, which brings benefits in terms of operational cost savings, promotes sustainability and optimal use of the radio spectrum. To ensure that the necessary navigation performance is preserved, the Distance Measuring Equipment (DME) plays a significant role, as DME/DME navigation is a short-term contingency solution when Global Navigation Satellite System is unavailable. Therefore, new DME ground stations are put into operation even though other navigation aids are being decommissioned at the same time. This paper addresses a question of possible DME network rationalization by developing a software model using a combination of a rule-based model, approximating of airborne DME interrogators interacting with DME ground transponders, with the implementation of the Gradient Boosting Regression to predict load of DME ground stations. The model is validated by comparing the results with the real load data obtained from an Air Navigation Service Provider. Several test cases are performed to evaluate the capability of the European DME network, simulating a reduction in the number of en-route DME stations and increases in air traffic using clustering methods. The results show that the ground station load limit was rarely reached, demonstrating the robustness and the potential for rationalization of the DME infrastructure.

Článek v periodiku excerpovaném SSCI

2024, The Aeronautical Journal, 1331 (129), p. 206-223), ISSN 2059-6464

The threat of GNSS interference poses a great danger to many critical infrastructure systems including air navigation. With a focus on mitigating this threat, this paper proposes a methodology for detecting GNSS interference. The methodology utilises the quality indicator NACp transmitted in ADS-B messages and GPS almanac data for interference detection. The NACp indicator enables estimation of the position error derived from GPS, which is compared with the HDOP value of the GPS satellite constellation. Based on this comparison, the developed detection algorithm determines whether the aircraft is affected by jamming. The detection methodology is evaluated on datasets obtained during deliberate experiments with GPS jamming. The proposed methodology provides a way to detect GNSS interference, facilitating mitigation of its impact on air traffic operation.

Článek v periodiku excerpovaném SCI Expanded

2024, New Trends in Civil Aviation: Proceedings of the 24th International Conference on New Trends in Civil Aviation 2024, Praha, České vysoké učení technické v Praze), p. 165-170), ISBN 978-80-01-07181-6, ISSN 2694-7854

This paper deals with the development of a software tool for visualization of current and predicted future air traffic. The software, implemented in the Python programming language, uses real air traffic data from the OpenSky Network that represents the general air traffic situation for further understanding of the distribution of aircraft over European airspace. The methodology includes clustering of initial air traffic data sets using various clustering algorithms and the Gaussian mixture model to generate or remove aircraft from air traffic that allows users to increase and decrease air traffic based on their needs, for example following the air traffic forecast, and observe the generated air traffic distribution enabled by the visualization. This work contributes to advancements in analyzing and visualizing the evolution of air traffic and enables simulations in different areas of Air Traffic Management where forecasting future air traffic is crucial.

Stať ve sborníku z mezinár. konf. cizojazyčně

2023, TRANSPORT MEANS 2023 Sustainability: Research and Solutions PROCEEDINGS OF THE 27th INTERNATIONAL SCIENTIFIC CONFERENCE PART II, Kaunas, Kaunas University of Technology), p. 334-339), ISBN 9781713879534, ISSN 1822-296X

The LDACS is the upcoming digital communication system in aviation, that is able to perform navigation and even surveillance service. This system by the time of writing of this paper LDACS is under certification standardization process by ICAO and considered by several alternative position navigation and timing (APNT) and future communication infrastructure (FCI) proposals. This paper deals with the process of designing the LDACS testing platform in order to support future testing and performance evaluations under different conditions. The paper starts with a basic description of the processes that are going on in LDACS transmitter and receiver. It highlights the main concepts and technology solutions for signal generation as well as forward error correction (FEC) methods that are used in LDACS signal generation process. The platform, proposed in this paper is designed on basis of official LDACS MATLAB simulation, provided by DLR. For the HW solution, ADALM-Pluto software defined radio system is used. Resulting platform is featured with wide range of setting possibilities and fully correspond to the LDACS specification. The last part of this paper is dedicated to the testing scenarios for the proposed platform as well as to the discussion of the transmission results. They include basic transmission without any interference and with different SNR levels, 3 transmission scenarios for en-route, airport, and terminal interference and noise conditions. Last but not least, scenarios with one and multiple DMEs are included.

Stať ve sborníku z prestižní konf. (Scopus)

2020, 2020 New Trends in Civil Aviation, Praha, IEEE Czechoslovakia Section), p. 39-43), ISBN 978-80-01-06726-0, ISSN 2694-7854

Automatic collection and processing of surveillance and flight related data is an essential task in commercial air transport nowadays. It is enabled by using an appropriate ground infrastructure and equipment onboard aircraft able to communicate and transfer data among each other. While in commercial air transport it is mandatory for aircraft of certain category to be equipped with these devices, in general aviation this is not normally required. However, uncontrolled airports with Aerodrome Flight Information Service, where most of air traffic represents general aviation, could benefit from using low-cost tools that would enable them to automatically collect information about aircraft movements. Nevertheless, for this to happen, it is necessary that also the aircraft are equipped with devices capable to transmit surveillance and preferably also other data on 1090 MHz. This paper analyzes the proportion of general aviation air traffic equipped with such devices at Prague Letnany Airport and evaluates how the automatic data collection could potentially help reduce the workload of dispatchers at the uncontrolled airports.

Stať ve sborníku z prestižní konf. (Scopus)

2020, MAD - Magazine of Aviation Development, 8 (4), p. 6-11), ISSN 1805-7578

The aim of this paper is to provide performance assessment of Alternative Navigation Positioning and Timing (APNT) systems considered possible GNSS backup in European region. The performance of the APNT systems is assessed based on their performance characteristics such as accuracy, integrity, and by additional beneficial abilities, that could help by implementation or could provide different added value in terms of solving certain issues in the Communication, Navigation and Surveillance (CNS) domain.

Článek v odborném recenzovaném periodiku cizojazyčně

2020, Transportation Research Procedia, Linz, Elsevier BV), p. 190-198), ISSN 2352-1465

The GNSS outage is regarded as a significant threat for the seamless air traffic operation not only above the mainland, but it may also affect the navigation performance over oceanic or remote areas. This research project deals with design and evaluation of two methods extending the coverage of terrestrial alternative navigation solutions by using technologies based on the current navigation and surveillance systems. Both solutions are represented by models enhancing the transmitted signal from ground stations (GS) by forwarding the signal, respectively, by exchange of necessary information among aircraft in surroundings beyond the line of sight of the GS. Afterwards, the Monte Carlo simulation has been applied for evaluation of position error of both proposed solutions. In conclusion, the suitability of the evaluated models is considered in relation to the current navigation means used in the remote areas.

Stať ve sborníku z prestižní konf. (Scopus)

2020, 2020 New Trends in Civil Aviation, Praha, IEEE Czechoslovakia Section), p. 123-128), ISBN 978-80-01-06726-0, ISSN 2694-7854

The ADS-B system is one of the key pillars of the future surveillance infrastructure, where the provided position information is predominantly dependent on the availability and quality of GNSS position information. The article presents the findings obtained during a real-time measurement in which the GNSS receiver within the multi-mode receiver (MMR) on the B737 MAX was interfered. In addition to identifying the power level sufficient to disable the GNSS receiver on this aircraft, the article further describes the behavior of the ADS-B system under jamming conditions. The experiment was performed on the ground, i.e., both the aircraft and the jammer were stationary during all phases of measurement.

Stať ve sborníku z prestižní konf. (Scopus)

2020, 2020 New Trends in Civil Aviation, Praha, IEEE Czechoslovakia Section), p. 9-15), ISBN 978-80-01-06726-0, ISSN 2694-7854

With the increasing dependency on the Global Navigation Satellite System (GNSS) for navigation and surveillance, aviation is focusing on mitigation of threats caused by a possible system unavailability due to jamming or spoofing. This research deals with pattern recognition of the time evolution of quality indicators in transmitted Automatic Dependent Surveillance - Broadcast (ADS-B) messages during GNSS jamming in non jammed data over Central Europe. An evaluation of the quality indicators from all messages within a one month interval is presented. A practical jamming experiment was done to determine how the quality indicators are changing during a jamming presence. Afterwards, the results of the experiment are used as a foundation for the proposed jamming detection technique using ADS-B data based on pattern recognition and cluster analysis. A natural presence of a quality indicators variability is proven in the data using these methods, similar to the indicators variability during GNSS jamming.

Stať ve sborníku z prestižní konf. (Scopus)

2019, TRANSPORT MEANS 2019 - PROCEEDINGS OF THE 23rd INTERNATIONAL SCIENTIFIC CONFERENCE, Kaunas, Kaunas University of Technology), p. 1128-1134), ISSN 1822-296X

Considering the requirements for the elementary and enhanced surveillance Mode S transponder capability within Europe, an amount of information contained in Comm-B replies of addressed surveillance has increased,and a varied data from on board of an aircraft may be obtained by a receiver onfrequency 1090 MHz. In order to decode the received flight data without the knowledge of the initial SSRinterrogation, the so-called BDS register number is necessary to determine. For this purpose, more algorithms have been created to identify the particular type of the Comm-B replies. This paper deals not only with a comparison of different approaches of the BDS number determining, but it also aims at finding the advantages of each algorithm for recommendation with a view to improve current solutions.

Stať ve sborníku z prestižní konf. (Scopus)

2019, TRANSPORT MEANS 2019 - PROCEEDINGS OF THE 23rd INTERNATIONAL SCIENTIFIC CONFERENCE, Kaunas, Kaunas University of Technology), p. 555-559), ISSN 1822-296X

Nowadays air navigation service providers (ANSP) use three main sources of surveillance information: SSR Mode S, MLAT systems, and ADS-B. Current cooperativesurveillance systems are typically characterized not only by determiningthe air targets position but also by acquiringa large amount of other aircraft-related information. The pressure to the interrogation of more and more information is constantly increasing. Unfortunately, all main above mentioned surveillance systems are based on sharing the same frequency band without any direct cooperation, which makes this problem even more difficult when no possible to count on the availability of any new cooperativesurveillance technology in the foreseeable future. The paperaims to show how would be possible to efficiently meet the current and future surveillance requirements by means of strengthening the cooperation of these systems. It alsodealswith the concept of complete removal of the so-called “All-Call” period from the SSR Mod S radar interrogation schemedeals in more, where excludingof the primary target detection capability would be compensated byreceiving of appropriate information from the MLAT or ADS-B system. Feasibility aspects and the benefits of this concept are discussed.

Stať ve sborníku z prestižní konf. (Scopus)

2018, Young Transportation Engineers Conference 2018, Praha, Fakulta dopravní), ISBN 978-80-01-06464-1

Contrails are line-shaped clouds formed behind aircraft which may persist for hours while growing to resemble cirrus clouds. Contrails cause positive radiative forcing which tends to warm the atmosphere. This paper describes the contrail formation, climate effect and contrail research carried out by the Department of Air Transport, Faculty of Transportation Sciences, Czech Technical University in Prague. The research is based on contrail observation, ADS-B messages, Mode S messages and aerological measurement. The aim of the research is to identify the frequency of contrail occurrence, their lifetime and other properties and compare them to meteorological conditions.

Stať ve sborníku z mezinár. konf. cizojazyčně

2018, Acta Avionica, 20 (1), p. 24-29), ISSN 1339-9853

The article is concerned with aircraft derived data and its applicability for condensation trails research. ADS-B messages, selected BDS registers and meteorological BDS registers are received on 1090MHz frequency and filtrated from the received data. Information received from on-board systems of the aircraft are selected only from a delineated monitored area, where contrails are observed. A methodical process is created for the purpose of assigning the corresponding aircraft and received data to the created condensation trails. The process is lately verified based on watching video records and pairing with the appropriate data obtained from the Department of Air Transport at CTU in Prague, Faculty of Transportation Sciences data warehouse. Condensation trails are classified into given categories and decoded information was assigned to them. Suggestions for possible improvement of the particular steps of the process are created based on previous verification.

Článek v odborném recenzovaném periodiku

2018, MATEC Web of Conferences, Les Ulis Cedex A, EDP Sciences - Web of Conferences), ISSN 2261-236X

The SSR Mode S technology is currently one of the major means of surveillance in ATM. Addressed surveillance enables the elicitation of replies from Mode S transponder on board of an aircraft containing different flight informatio n in the so-called BDS registers. The type of BDS register as well as its content is characterised by a number of the BDS registers which is determined according to SSR interrogation by default. The study deals with the development of a heuristic algorithm for identification of a particular BDS register with the assumption that the radar query is unknown. A BDS number is assigned to the appropriate message on the basis of the unique bit sequences and other criteria. The algorithm provides the opportunity to obtain various flight data from the aircraft by only receiving addressed surveillance replies on 1090 MHz frequency.

Stať ve sborníku z prestižní konf.