ABSTRACT: 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.

KEYWORDS: Marine Navigation, Global Navigation Satellite System (GNSS), Navigational System, Ground-Based Augmentation System (GBAS), 21st Century Challenges, Radio Navigation, ALFA System, Ground-Based Radionavigation System

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