Russian Tundra Satellites Jam Europe’s GPS

The GPS signal that guides a phone, aircraft or ship reaches Earth after travelling 20,000 km from orbit. By then it is weaker than the thermal noise of stars and sunlight. It works because the receiver knows exactly which signal to isolate from the background.

Put a stronger transmission on an almost identical frequency and the system loses that signal. Across Europe, from Iceland to Italy, this has happened at least 75 times since 2019. The source is not a mast on the ground. It is a constellation of Russian military satellites orbiting as high as 45,000 km above Earth.

Pinpointing a satellite by its shadow

Researchers at the University of Texas, led by Prof. Todd Humphreys and student Zachary Clements, spent years examining sudden drops in GPS signal quality recorded by monitoring stations across Europe. Each incident showed the same pattern: the navigation signal fell by roughly a factor of ten, at the same time, across receivers thousands of kilometres apart. A ground-based jammer cannot do that over such a distance because the curvature of the Earth gets in the way.

The source was traced to Russia's Tundra satellites, part of the EKS/Kupol early-warning system, built to detect ballistic missile launches. These satellites move in highly elliptical orbits, spending long periods near their highest point while looking down over the Arctic and Northern Europe. Their main job is to watch for rocket plumes. Their downlink transmissions to Earth operate at 1,577.5 MHz, just 2.5 MHz from the GPS L1 frequency at 1,575 MHz. With a powerful enough transmitter, that gap is small enough for energy to spill into the GPS band.

The researchers confirmed the source through time-difference-of-arrival analysis. In simple terms, they measured the tiny difference in time between an interference burst reaching two distant stations, including Amsterdam and Trondheim, 1,500 km apart. That difference places the source on a shell-shaped surface in space. Add enough station pairs and the shells meet at one point. Only one satellite was there: Cosmos 2546, matching to within 200 metres. Spanish technology firm GMV independently corroborated the findings using similar methods.

A frequency that spares only GLONASS

The interference affects GPS, the American system; Galileo, Europe's system; and BeiDou, China's system. It does not affect Russia's own GLONASS system. The frequency appears to avoid Russian self-disruption while hitting every competing navigation network. Researchers have not yet established whether that was deliberate design or a convenient engineering outcome. A US Air Force briefing acknowledged the interference but did not publicly assess intent.

Each disruption lasts less than ten seconds and is synchronised with a satellite pass. Most devices recover by falling back on their last known position. Aircraft face the sharper operational problem. Commercial planes have backup systems, including inertial navigation and ground-based radio beacons, but losing GPS adds work in the cockpit and reduces the precision of modern approach procedures that rely on satellite positioning. For Malta, where air and sea links are lifelines rather than background infrastructure, that distinction matters.

Europe's defence has a blind spot

Europe's main countermeasure, Galileo's OSNMA authentication system, live since July 2025, allows receivers to verify that a navigation message really comes from a Galileo satellite. That helps against spoofing, where false signals are broadcast to trick a receiver. Russia has used that tactic through Kaliningrad's expanding network of 36 ground-based transmitters. OSNMA cannot solve jamming. If noise drowns the signal, there is no message left to authenticate.

The larger weakness is detection. European security planning has treated GPS interference mainly as a ground-based threat. Space-based jamming is now documented, but Europe has limited means to track it itself. France is the only European country with an orbital detection capability: its NESS nanosatellite, launched in 2023, carries instruments designed to characterise interference sources from orbit. Germany plans to launch its own monitoring satellites in autumn 2026. Until then, Europe depends heavily on American academics and ground-station data to identify threats coming from 45,000 km overhead.

The longer-term answer is a European low-orbit navigation constellation called Céleste, designed to transmit stronger signals that are harder to jam. It is not expected to be fully operational before the mid-2030s. Europe already knows that parts of its navigation system are being drowned out from space. Its problem is that it still lacks the tools to watch the source directly.