Aviation prepared for GPS interference: It is safe to fly in and to Finland

GPS interference has occurred for the past twenty years during the time in which GPS has been used in aviation as a navigation system. Problems in technical systems are possible. Aeroplanes have alternative navigation systems to ensure a safe flight. 

“It is still safe to fly to and in Finland. GPS interference is not a new phenomenon in aviation and that is why we are prepared for them. Reports of interference have increased during the past year. GPS interference affects the planning and ease of transport and the schedules of travellers more than safety,” states Director-General Jarkko Saarimäki.

The Finnish Transport and Communications Agency Traficom has received an increasing number of reports of GPS interference in aircraft outside of Finland and over Finnish soil during the current year. Interference detected in Finnish territory is typically reported to Traficom by air navigation organisations and Finnish airlines, who also report to the Agency about interference detected abroad.

Although GPS is now the main source of navigation information in aviation, there are several alternative navigation systems, especially in passenger aircraft, such as inertia-based navigation and ground-based navigation. Additionally, air traffic control can aid with navigation if necessary. For example, by vectoring, an aircraft is given guidance directions that, by flying according to them, it can continue on the route or approach.

The impact of GPS interference on aviation

The most notable effect in individual cases is that the flight has not been able to land at the destination airport but has had to fly to a backup airport. These situations have been caused by the fact that the planned landing field has not had navigation equipment that could have been used by the aircraft to carry out the approach in the event of GPS interference. In this case, you land on a backup field, where you can land without GPS positioning. All flights have a pre-defined backup field. 

The amount of navigation assistance provided by air traffic control has increased, which is part of the normal operation of air traffic control. 

Analysis on the reason behind GPS interference

In general, radio interference can be caused by e.g. faulty radio or electrical equipment, and the system's susceptibility to interference depends on the radio system. Global Navigation Satellite System (GNSS) signals are muted when entering the ground from a satellite, making GNSS reception sensitive to various interferences. The GNSS reception of services used by citizens is easily disrupted by, among other things, environmental blind spots. In addition, atmospheric phenomena can interfere with GNSS reception. 

An interference situation can also be caused intentionally, in which case it is jamming. In aviation, disturbances in satellite navigation systems are often observed especially in the vicinity of conflict zones. In conflict zones or in the vicinity of these, jamming is typically used to protect one's own infrastructure or important sites, so the interference effect can also spread more widely. 

The interference intensified when Ukraine's drone attacks on Russia's energy infrastructure began in January 2024. It is possible that the interference observed in aviation currently are most likely a side effect of Russia's self-protection. In practice, self-protection interference is used to prevent the navigation and control of drones controlled by GNSS or mobile frequencies. The interference has not only remained within Russia's borders, but has also reached Finnish territory.