Something is Jamming GPS Over Europe — and the RF Physics Behind the Hunt

The signal that runs the world

GPS does far more than draw a blue dot on a map. It is the invisible heartbeat of power grids, banks, and phone networks — a precise clock in the sky. So when GPS started failing across Europe, it was worth finding out why.

To understand what went wrong, you first need to see how something so useful can also be so fragile. We'll build it up in four steps: how GPS finds you, why its signal is unbelievably faint, how a cheap device can blind it, and finally how investigators tracked the interference back to its source.

Try it as you read: the interactive version of this story — with a 3D globe, a drag-the-jammer meter, and a detective case — lives at /learn/gnss-jamming.

How GPS works

There are no maps stored in the sky. A GPS satellite does just one clever thing: it carries an atomic clock and constantly broadcasts the exact time. Your phone receives that message, compares it to its own clock, and sees how long the signal took to arrive. Radio waves travel at the speed of light, so that tiny delay converts directly into a distance.

One distance alone isn't enough — it only tells you that you're somewhere on a sphere around that satellite. But add a second satellite and the two spheres overlap in a ring; a third narrows it to a single point. This is trilateration: not measuring angles, just distances.

There's one catch. Your phone's clock is cheap and drifts, and even a millionth of a second of error throws the distance off by hundreds of metres. That's why you actually need a fourth satellite: the extra measurement lets the receiver solve for its own clock error at the same time as its position. Four satellites in view, and you know where — and when — you are.

Why the GPS signal is so faint

Here is the part that surprises everyone. By the time a GPS signal has travelled ~20,000 km to the ground, it is weaker than the background radio noise around you — about −127 dBm. That's like trying to spot a single 25-watt light bulb from the other side of a continent.

So how does any receiver hear it? With a trick called spread-spectrum processing. The satellite hides its message in a known, repeating code; the receiver, knowing that exact code, can correlate against it and pull the signal back up out of the noise — adding roughly 43 dB of "processing gain." It works beautifully. But notice how thin the margin is: the system depends entirely on that faint signal staying just a little above the noise.

What's the issue — jamming

That thin margin is the whole problem. A jammer doesn't need to be clever or powerful. It just transmits noise on the GPS frequency, and because the real signal is already so weak, even a cheap battery-powered device nearby can lift the noise floor above the signal. Once that happens, no amount of processing gain helps — the receiver simply loses its lock.

This is why GPS jamming is so disruptive and so hard to stop: the attacker has a massive advantage. The satellite is shouting from 20,000 km away; the jammer is whispering from down the street, and the whisper wins. Drag the jammer's power and distance in the interactive meter and watch exactly where the lock disappears.

The hunt — where is it coming from?

When interference blankets an entire region at once, a single jammer by the roadside can't explain it. So investigators do detective work on the signal itself. Two clues matter most: the direction the interference arrives from (measured with directional antennas), and its Doppler shift — the way its frequency slides up and down as the source moves relative to the receiver.

A stationary ground transmitter has almost no Doppler shift. A fast, smoothly changing shift means the source is moving — and the way it changes tells you how fast and along what path. In a 2026 study, those clues pointed not at the ground at all, but upward: to a powerful source passing overhead in orbit.

Why it matters

Losing GPS is not just about getting lost. The same signal that guides ships keeps power grids, financial networks, and telecoms synchronised to a shared clock. Understanding how GPS works — why it's fragile, how it can be disrupted, and how interference can be located — is the first step to making it resilient.

Sources & Further Reading

• Clements, Z. L., Kriezis, A., & Humphreys, T. E. (2026). Chasing Lightning: Detecting, Characterizing, and Identifying a Powerful Space-Based GNSS Interference. UT Austin Radionavigation Lab. ve42.co/GNSSInterference
• Full reference list: ve42.co/GPSJammingRefs
• Veritasium (2026). Something is jamming GPS over Europe. Here's what we found. youtu.be/tz23G_UXCGA
• Bartosz Ciechanowski — interactive GPS explainer. ciechanow.ski/gps
• Resilient Navigation and Timing Foundation. rntfnd.org
• KeepTrack satellite tracker. keeptrack.space

This article summarizes publicly reported research; specific attributions of any single event follow the cited study rather than independent claims.