Loading the day…
Aircraft find their position by satellite (GNSS: GPS, Galileo and the others). Near the Baltic these signals are often jammed, and aircraft then fly on their other navigation systems. We see it in what each aircraft broadcasts about how accurate its own position is.
Where
Where aircraft lost it, and where it might come from
Aircraft that lost GNSS in each area today.
Arrivals and departures that lost GNSS within 50 km of the airport, below about 4 500 m (FL150). Arriving or leaving is read from the flight's route; a flight with no known route counts as passing.
When
Hour by hour, and the events still going on
An estimate from ADS-B, not a measurement.
What the authorities say
GNSS warnings in force around the Baltic, from NOTAMs
Why it is interference
The satellites were there
The last 7 days, by FIR
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| Flights | Affected | Jammed | Spoofed | Both |
|---|---|---|---|---|
A spot where two aircraft or more were reported within 2 km and 30 minutes of each other while a spoofing check fired: a false position, not where they flew.
How we know, and what we can't see
Every aircraft with ADS-B broadcasts its position about twice a second, together with two quality figures: how accurate the position is (NACp) and the margin its navigation system guarantees (NIC). When the satellite signal is jammed these figures collapse. We count an aircraft as having lost GNSS when either falls to 4 or less (NIC 4 is under 2 NM, NACp 4 is under 1 NM), or when the receiver network can only place it by timing its signal from the ground (multilateration) because its own satellite position is gone.
Aircraft affected are aircraft that lost GNSS at least once during the day (one aircraft flying several legs counts once) inside the area we record: 250 nautical miles (463 km) around the Gulf of Finland and around the southern Baltic, the two circles on the map. Aircraft whose figures are low wherever they fly, with every aircraft around them fine, have faulty equipment, not jamming, and are left out; so are losses in a steep turn, when the antenna faces away from the sky. Time without GNSS adds up each aircraft's losses; a loss we could not see end (the aircraft left our view still jammed) counts until the last time we saw it, so the total is a minimum.
Likely sources follow the method SeRo Systems published with the Estonian air navigation service and the Consumer Protection and Technical Regulatory Authority ("Jammer on the Horizon", ION GNSS+ 2023): a jammer reaches as far as its radio horizon, so an aircraft losing or regaining GNSS is crossing that horizon, and where the horizons of several aircraft meet is the likely source area. When too few aircraft cross an edge, or several jammers overlap, no source is given rather than a guess.
What we can't see. Outside the two circles we only see what someone happened to be watching, so it is not counted here. Aircraft without ADS-B, and many military aircraft, report no quality figures. The data comes from volunteer receivers through adsb.lol; where the receivers are few, or the recording had a gap (shown as a dashed hour), losses go unseen. This page reports what aircraft broadcast; it says nothing about who is jamming or why, and it is not a safety assessment.
ADS-B data © adsb.lol contributors (ODbL). Map © OpenFreeMap, OpenStreetMap contributors. Ampron Sky by Ampron, Estonia. Not for navigation.
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