Websites like adsbexchange.com log ADS-B aircraft tracking data from contributors located all over the world and aggregate it all onto a single map. Typically an RTL-SDR is the receiver of choice for contributors receiving ADS-B signals. One piece of data that is recorded with each packet is GPS/GNSS accuracy.

Over on Twitter John Wiseman @lemonodor has been using the aggregated ADS-B data provided by adsbexchange to highlight regions where ADS-B GPS inaccuracies are significant. This may allow us to use crowd sourced data to detect regions of GPS interference or jamming. In one of his latest findings he noted extreme GPS inaccuracy that noticed around the Baltic regions (Poland, Lithuania, Latvia, Kaliningrad).

I thought making maps of GPS/GNSS interference might turn out boring. But 3 days ago suddenly the Baltic (Poland, Lithuania, Latvia, Kaliningrad) started having some of the most significant interference on the planet, after weeks of nothing unusual. Why now? pic.twitter.com/Hnwh6Hgjmk

— John Wiseman (@lemonodor) March 7, 2022

As John and others reported in subsequent Tweets, this GPS interference was noticed by others too, with some flights needing to be cancelled or needing to return during their journey, and a NOTAM warning being issued to pilots regarding the interference. Reuters also reported on the GPS disturbance a few days later.

NOTAM: GPS INTERFERENCE DETECTED IN THE EASTERN PARTS OF HELSINKI FIR. AFFECTED AREA SECTOR N, SFC-FL200

It is well known that Russia routinely utilizes GPS spoofing or jamming around Kremlin landmarks, sensitive areas and during military operations. However, others noted that NATO exercises in the Baltic could also be the cause.

To further add to this story, the satellite intelligence operator Hawkeye 360 also recently detected significant GPS interference within or around Ukraine.