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Is It Permissible to Use GPS Data to Avoid Collisions?

Felski Andrzej, Jaskólski Krzysztof

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2025

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Vol. 19 No. 2

347--354

EN

Automatic Radar with Plotting Aids is the basic means of preventing collisions at sea for many years. However, the use of the radar on a moving vessel requires image stabilization, which has been at least for the last 50 years solved by coupling with the gyrocompass and the log. In the present century, the widespread use of Global Navigation Satellite System receivers has led to the common practice of interconnecting this receiver with many other systems on ships. This is often also the case for radar, although GNSS gives information about movement related to the ground, whereas the International Maritime Organization recommends using parameters relating to water. The mandatory and widespread equipping ships with the Automatic Identification System means that this system is increasingly used in the process of collision avoidance, but also with the use of ground-referenced data. The aim of the paper is to investigate whether this is acceptable and what are the limits of this practice. This question becomes increasingly important in the context of the growing number of unmanned vessels. Not all, especially small autonomous surface vehicles will be equipped with radar and may also use AIS transmissions in collision avoidance algorithms. Studies have shown that this may pose a risk of collision. At low ship speeds, if the current speed exceeds 5 knots and the direction of the current significantly deviates from the course of one of the ships, there is a risk that the planned maneuver will not be carried out. This may mean that the closest approach distance will be significantly different from the planned one.

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Threats for GNSS - present status & counteractions

Felski Andrzej

Annual of Navigation

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2024

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No. 29

16--24

EN

Nowadays, most of the society, especially young people, treat GPS as an obvious source of information, just like television, radio or the Internet. In fact, we are dealing not only with the American system, but also several others that make up Global Navigation Satellite Systems. This is the primary source of situational awareness for many activities: professional, military and business as for everyday use. From crisis actions, by timing and synchronization in critical infrastructures such as financial, communications, power grid and industrial systems, and more. In fact, we can talk about the critically reliant of human life upon GNSS. Like any radio system, GNSS is also susceptible to interference and changes in the ionosphere, however on the turn of the centuries appeared the new, not expected threat in the form of more and more frequent cases of interferences, especially intendent one. If so, appears the question how to recognize this threat and how to proceed in such case? In the paper, some current information about the question, as well as some suggestions how to act on board in such cases will be presented.

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Software defined radio and open software as a critical threat for unmanned objects

Felski Andrzej, Kowalik Tomasz

Aviation and Security Issues

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2023

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No. 1

255--264

EN

Implementation of the Global Navigation Satellite Systems into almost all aspects of life causes the specific, new troubles in the form of jamming and spoofing. The origin of the problem comes from the fact that power of received signals are weak, and format and modulation of the signals are publicly known. If so, it seems to be easy to transmit falsified data to the receiver. However in the opinion of some specialists the idea to generate false signals with GNSS structure seems to be very complicated. In this paper will be shown that in fact, this can be conducted with use of cheap and widely accessible tools, without demanding any extraordinary skills nor great funds. If so, this threat gathers the new meaning. Described experiment was performed within the framework of student’s thesis on major navigation with the cheap software defined radio and open sources software, accessible via Internet.

PL

Zastosowanie globalnych, satelitarnych systemów nawigacyjnych w niemal każdym aspekcie życia powoduje powstanie specyficznego, nowego zagrożenia pod postacią zagłuszania lub fałszowania sygnałów satelitarnych. Przyczyną problemu jest to, że sygnały docierające do Ziemi są niezwykle słabe, zaś ich struktura i sposób modulacji są powszechnie znane. W tej sytuacji nietrudno wyemitować w kierunku odbiornika sygnały fałszywe. Jednak w opinii wielu specjalistów próba wyemitowania fałszywych sygnałów posiadających taką strukturę jak te, które są emitowane przez satelity, wydaje się niezwykle złożona. W artykule wykazano, że w istocie można tego dokonać, posługując się tanimi i powszechnie dostępnymi narzędziami bez potrzeby posiadania nadzwyczajnych umiejętności lub funduszy. Jeśli tak, to zagadnienie nabiera nowego znaczenia. Opisany eksperyment został wykonany w ramach pracy nad pracą magisterską z nawigacji w oparciu o tanie radio programowalne oraz bezpłatne, dostępne za pośrednictwem Internetu oprogramowanie.

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The Russian ALFA system in the context of thedevelopment of radionavigation in the 21st century

Felski Andrzej

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2021

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Vol. 15 No. 4

723--728

EN

For nearly the entire post-World War II period, naval and air navigation relied primarily on ground-based radionavigation systems. However, the spontaneous development of satellite systems gradually led to their disappearance. They are currently used partly in air operations and marginally in maritime navigation in some areas around Asia, in Russia and in the Middle East. However, at the beginning of the 21st century, the threat of effective interference with satellite systems began to be raised, which led to an increased interest in restoring or upgrading ground-based systems as backup systems in the Western world. In this context, the approach of Russia is interesting, as it is associated with the vast majority of deliberate GPS interference. There are reports in the world literature that various ground-based radionavigation systems operating in Russia are still observed. The article analyses, on the basis of the few available sources, information on the ALFA system, about which the least is known, and there are many indications that it is ready for use.

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Possibilities of detection of the Jamming of the GNSS receiver with the helical antenna

Felski Andrzej, Stopienski Piotr

Scientific Journal of Polish Naval Academy

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2020

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R. 61 nr 4 (223)

21--37

EN

Jamming of GNSS signals is lately treated as essential threat for GNSS users. It is especially dangerous in the face of common usage of GPS-like systems in everyday life, and the great belief of everyday users in the truth of devices indications. In spite of the legal prohibition of using them, jammers are commonly accessible, especially in the Internet. Last years showed however that such threat generated purposely also some governments, what is clearly visible in armed conflicts, and during military exercises. Of course this creates the great threat for civilian users if will be in the vicinity. Applications and services based upon GNSS are becoming increasingly embedded in modern society, so community have now become critically dependent upon their correct operation. This refers positioning first of all, but telecommunications networks, power grids, financial transactions, whole world of logistics are dependant as well. The main users of GNSS, both professional and non-professional smartphones users are not prepared on such situation, and usually have no technical possibilities to detect of jamming. For operators of critical installations, for example seaports, or airfields, the detection of jamming cases is extremely important. It can be provided with special devices, which are usually based on specific antennas, and deep analysis of signal. In this paper experiments in detection of the jamming with helical antennas are discussed.

PL

Zagłuszanie sygnałów GNSS traktuje się ostatnio jako istotne zagrożenie dla użytkowników GNSS. Jest to szczególnie niebezpieczne w obliczu powszechnego stosowania systemów typu GPS w życiu codziennym oraz wiary użytkowników w prawdziwość wskazań urządzeń. Mimo prawnego zakazu ich używania jammery są powszechnie dostępne, zwłaszcza w Internecie. Ostatnie lata pokazały jednak, że takie zagrożenie celowo generowały również niektóre organy rządzące, co widać wyraźnie w konfliktach zbrojnych i podczas ćwiczeń wojskowych. Oczywiście stwarza to wielkie zagrożenie dla użytkowników cywilnych, jeśli znajdą się w zasięgu. Aplikacje i usługi oparte na GNSS są coraz częściej osadzone we współczesnym społeczeństwie, więc społeczność stała się obecnie w decydującym stopniu zależna od ich prawidłowego działania. Dotyczy to przede wszystkim pozycjonowania, ale zależne są też sieci telekomunikacyjne, sieci energetyczne, transakcje finansowe, cały świat logistyki. Główni użytkownicy GNSS, zarówno profesjonalni, jak i nieprofesjonalni użytkownicy smartfonów, nie są przygotowani na taką sytuację i zwykle nie mają technicznych możliwości wykrycia zagłuszania. Dla operatorów instalacji krytycznych, na przykład portów morskich lub lotnisk, wykrywanie przypadków zagłuszania jest niezwykle ważne. Jest to możliwe za pomocą specjalnych urządzeń, które zwykle opierają się na określonych antenach i głębokiej analizie sygnału. W artykule omówiono badania dotyczące wykrywania zagłuszania za pomocą anten śrubowych.