The signal in question is called the Global Navigation Satellite System, or GNSS. Most people know it by the name of the specific American constellation that first made it publicly available, GPS. In practice, four separate satellite constellations are currently in operation: the American GPS, the European Galileo, the Russian GLONASS, and the Chinese BeiDou. Modern civilian receivers use signals from all four in combination.

The signals themselves are extraordinarily faint. Each satellite transmits from an orbit approximately 20,000 kilometres above the Earth’s surface, using a transmitter power of approximately 27 watts, which is comparable to a small household light bulb. By the time the signal reaches the ground, its strength has fallen by a factor of approximately one hundred billion. A GNSS receiver on Earth is, in effect, detecting a light bulb switched on above the Atlantic Ocean from a chair in Warsaw.

Because the signal is so faint, it is trivially easy to overwhelm. And that is what has been happening across large parts of European airspace, and the Baltic Sea and Black Sea regions specifically, on a near-daily basis since Russia’s full-scale invasion of Ukraine in February 2022.

The mechanism

GNSS works by precise measurement of arrival times. Each satellite carries an atomic clock and continuously broadcasts a timestamped signal identifying itself. A receiver on the ground picks up signals from four or more satellites simultaneously, compares the specific times at which each signal arrived, calculates the differences in distance to each satellite from those time differences, and solves the resulting geometry to produce a three-dimensional position fix. The system is used not only for navigation but for high-precision time synchronisation across every network that depends on coordinated timekeeping.

Two forms of deliberate interference are currently in widespread use in European airspace. According to the European Union Aviation Safety Agency’s dedicated GNSS Outages and Alterations page, updated most recently in Safety Information Bulletin 2022-02R4 issued on 3 July 2026, the two forms are technically distinct.

Jamming is the simpler technique. It involves transmitting broadband radio noise on the same frequencies the satellites use. The noise overwhelms the faint satellite signal at any receiver within the transmitter’s coverage area, and the receiver reports a loss of lock. The system knows it has lost the signal, and it fails safely to alternative sensors.

Spoofing is the more dangerous technique. It involves broadcasting counterfeit satellite signals, carefully synchronised to appear authentic to a receiver but encoding false position or false time data. The receiver locks onto the fake signal, treats it as real, and produces a confident position fix that is systematically wrong. The system does not know it has been fooled. Any downstream system that trusts the position fix inherits the error.

This video goes into more detail:

What is happening over Europe

The specific operational picture across European airspace has been documented in extensive detail by EASA, EUROCONTROL, IATA, and the Council of the European Union.

Since August 2024, GNSS jamming and spoofing incidents over the Baltic Sea, the Mediterranean, the Middle East, the Black Sea, and the Arctic have escalated from occasional to routine. Data from IATA’s Global Aviation Data Management Flight Data eXchange indicates that GPS signal loss events increased by approximately 220 per cent between 2021 and 2024. EUROCONTROL data presented in IATA’s Safety Risk Assessment, and cited in the Council of the European Union’s 22 May 2025 policy document on the topic, recorded approximately 1,500 flights per day experiencing spoofing by August 2024. The Council document, on the strongest current reading, attributed the increase primarily to sources in Russia and Belarus.

The specific effects reported by airline crews and ground systems have been consistent. According to an EASA and IATA joint press release issued on 18 June 2025 outlining the current mitigation plan, the operational consequences include incoherent navigation positions, abnormal differences between ground speed and true airspeed, sudden time and date shifts on flight management systems, spurious terrain awareness and warning system alerts at cruise altitude, loss of Airborne Collision Avoidance System functions, and diversions or missed approaches. In January 2025, a passenger aircraft on final approach to Vilnius, Lithuania, abandoned its landing at approximately 850 feet above the runway after its instruments began reporting false position data. The aircraft diverted to another country. No mechanical fault was identified.

The four domains

Aviation is the most visible affected sector, but it is not the only one. GNSS provides two related services simultaneously. Position, which is the location of the receiver. And precise time, which is the synchronised universal timestamp used by any system that requires multiple parties to agree on when something happened.

Financial systems depend on GNSS-derived time signals to timestamp transactions. Bank transfers, stock trades, high-frequency trading orders, and interbank settlement systems all rely on coordinated timing accurate to within milliseconds, and the specific source of that coordinated time on many market infrastructures is a GNSS receiver mounted on the roof of the data centre. Regulatory requirements in the European Union, under the Markets in Financial Instruments Directive, mandate that certain classes of financial transactions must be timestamped to within one hundred microseconds of coordinated universal time. GNSS is the specific mechanism most institutions use to comply.

Electrical power grids depend on GNSS-derived time signals to synchronise the phase of alternating current across large geographic areas. Phasor measurement units at substations across a grid use GNSS time to timestamp measurements of voltage and current, allowing grid operators to detect and respond to instabilities in real time. A prolonged spoofing attack on the timing signal used by power infrastructure could, on the accumulated evidence of controlled experiments performed by academic research groups since 2012, degrade the specific stability margins that keep large interconnected grids from cascading failure.

Mobile phone networks depend on GNSS-derived time signals to coordinate handoffs between cell towers. As a device moves through a network, adjacent towers must agree on precisely when to hand the connection between them. The specific timing source that keeps the towers synchronised, at most operators, is a GNSS receiver.

Container shipping, road freight logistics, emergency services dispatch, agricultural machinery, surveying and construction, and the entire commercial drone industry all depend on GNSS for position or time or both.

The regulatory response

The Council of the European Union has classified the current pattern of GNSS interference as a hybrid warfare threat. On 6 June 2025, ministers from 13 EU Member States, including Lithuania, Latvia, Slovakia, Germany, Estonia, Finland, Slovenia, Czechia, Italy, the Netherlands, Spain, Denmark, and Romania, signed a joint letter to the European Commission asking for immediate coordinated action. According to EuroWaypoint’s analytical breakdown of the resulting document, published in May 2026, EASA and EUROCONTROL responded through a joint action plan released on 26 March 2026 comprising 22 specific measures across four workstreams (human performance, organisational management, aircraft design, and infrastructure), spanning improved reporting standards, tighter export controls on commercial jamming devices, stronger technical mitigations against false terrain warnings, and the mandated maintenance of a Minimum Operational Network of traditional non-GNSS navigation aids, including instrument landing systems, VOR beacons, and distance-measuring equipment.

Estonia, Finland, and other Baltic states have formally accused Russia of the disruptions. Russia has denied involvement.

The International Civil Aviation Organization has been monitoring the pattern as a threat to civil aviation safety and, on the current best available information, is expected to move formal standards on GNSS interference reporting and mitigation forward at its next assembly.

What the case shows

The specific technical vulnerability being exploited over Europe is not a bug in the design of GNSS. It is a direct consequence of a deliberate design choice made in the 1970s and 1980s, when the civilian GPS signal was first specified. The signal was made unencrypted and unauthenticated, so that any receiver anywhere in the world could use it without permission from any government. That decision produced the global positioning revolution of the past four decades. It also produced the specific structural vulnerability that a receiver has no cryptographic way to verify that the signal it is receiving actually came from the satellite it claims to have come from.

Newer GNSS constellations, including the European Galileo system, have begun to incorporate cryptographic authentication features that will, over time, make spoofing substantially more difficult. But most receivers currently deployed cannot use those features, and the specific transition to authenticated signal reception across the global installed base will take on the order of decades.

In the meantime, one faint signal from space continues to run large parts of modern civilisation. And in the specific parts of Europe closest to the current conflict, that signal is being jammed and spoofed at scale, on purpose, on a near-daily basis.

The mitigations exist. The costs are known.

The question of whether the industrial world can afford to keep relying on a single unauthenticated broadcast from twenty thousand kilometres up, in an era where the specific act of falsifying it has become cheap enough for any competent adversary to attempt, is being answered right now over the Baltic Sea.