auonsson Profile picture
Apr 29, 2024 13 tweets 5 min read Read on X
The GPS-jammer affecting aircrafts around Estonia is located in Russia, about halfway to St Petersburg from Narva, Estonia.

This is shown by plotting the highest density of intersecting radio horizons of jammed aircrafts on a map.

Further, a drone-based method supports it.🧵 Image
The GPS-jammer affecting aircrafts around Estonia is located in Russia, about halfway to St Petersburg from Narva, Estonia.

This can be shown by plotting the highest density of intersecting radio horizons of jammed aircrafts on a map.

Further, a drone-based method supports it. Image
This is a more zoomed in view of the likeliest position of the GPS-jammer operating around Estonia and recently famous for causing the brand new Helsinki - Tartu flight line to cease operating.

See this and linked posts for methodology. Image
This took some time to make so I will continue the thread tomorrow with drones, more radio horizons and closer explanations.

Data available if interest is shown. Stay tuned. Image
I should add. The jammer over Estonia is very different in scope and temporal profile. A higher proportion of aircrafts are affected around Estonia and the jammer is almost always on. See plots. Image
Proportion measure (%) is a bit skewed during nights though, because there are so few planes in the air. And this effect is even stronger around Estonia. Plots show last months total number of observations for respective area. Image
Estonia jammer is south-west of St Petersburg, part 2: drone proof!

Drone photographer @kristjanlust made this beautiful flight in Narva, pointing east. At altitude 60 meter all GPS is gone. This gives us a new radio horizon.

The horizon intersects* with location shown by me.
This drone method is very exciting since it is a direct observation, not mediated by translation through ADSb-layers.

It just shows: at this exact position the jammer jams from 60 meter and up.

Very useful!
Map of drone flight position, its radio horizon and previously found jammer position.

*As you can see, they dont match perfectly. We are ~20 km off.

Given unknown margins of errors of mine and horizon method and jam height I assume they actually overlap. Open to protests! Image
If we move our center to to the most likely position, use to find the highest peak within 15 miles and assume an antenna height of 50 meter we get these jam-radio horizons.

Almost all jammed positions are within the reach of a transmitter at that point. heywhatsthat.comImage
So, we have two ways of saying that the jammer is SW of St Petersburg.

If we test that hypothesis we get a radio horizon that contains most actually jammed aircrafts. So, we predict what actually happens.
None of this would have been possible without this excellent code by @PajalaJussi Thank you and sorry for no initial credit.

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More from @auonsson

Sep 13
A Russian brand new fishing boat is almost blocking Öresund strait.

They seemingly lost propulsion 4 hours ago, drifted north towards the very narrow channels (~300m) but seem to have anchored.

Swedish coast guard and police have been at scene.

AIS-caveats apply.
A Russian brand new fishing boat is almost blocking Öresund strait.

They seemingly lost propulsion 4 hours ago, drifted north towards the very narrow channels (~300m) but seem to have anchored.

Swedish coast guard and police have been at scene.

AIS-caveats apply. Zoom in.
Fishing boat in question is built this year 2025. Left St Petersburg about 3 days ago.

MECHANIC STEPANOV IMO: 9916252
Read 14 tweets
Sep 9
This is the main logistics hub for armaments into Ukraine.
Tanker (and hence fighters) inbound, Italian AEW&C inbound. Image
Polish AirborneEarlyWarning&Control aircraft landed a few minutes ago. Image
Read 4 tweets
Sep 6
I thought I had found indications of a targeted GNSS jamming attack against president von der Leyen's aircraft this Sunday.

Then I disproved my own hypothesis. Here's how!

This is common for me, I usually don't show it because it takes a lot of effort to explain also 0-results
Hypothesis: if vdLeyen-flight was jammed by a directional jammer other aircraft in the emission cone would also be affected

I got the idea upon looking at an animation by @lemonodor

Marked flight began reporting bad GPS-values just as the pilot of vdL reported issues over radio Image
Animation I refer to available at this link: bsky.app/profile/lemono…
Read 9 tweets
Sep 2
Swedish island Gotland is completely without power, for the second time in two weeks.

Gotland is considered paramount to NATO control of Baltic Sea.

As far as I know last outage is still being analyzed and cause is not known.

svt.se/nyheter/lokalt…
Power company now claims lightning strike as cause.

Article linked was updated.
Last hours lightning around Gotland. Image
Read 7 tweets
Sep 2
Pilot of the aircraft carrying president von der Leyen experienced GPS issues as they approached Plovdiv airport, Bulgaria Sun Aug 31.

Recordings of tower and plane comms are clear.

Transponder reported good GPS-signal and is likely separate from the instrument pilots used.
Half an hour after first reporting GPS-issues the aircraft of von der Leyen is taxiing on Plovdiv airport as the pilot repeats "we had GPS-issues" and thanks the flight controller for the support.

Full recordings with additional comms available at liveatc.net
From this we can derive that the pilot did *experience* GPS/GNSS-issues.

Given the area and years of jamming it is likely to have been caused by the common jamming of area.

Other explanations are possible.
Read 25 tweets
Sep 1
The plane carrying EU top Ursula von der Leyen was forced to land manually after being hit by GPS/GNSS jamming.

News texts seem to indicate it was directed specifically at Von der Leyen and the airport Plovdiv.

"GPS around airport was knocked out for an hour."
Image
Image
Read 17 tweets

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