Thread by @auonsson

Ships in south Baltic Sea are seeing GPS interference. Stated by SE authorities, individual reports and is subtly seen in replays of ship traffic.

While the area has long been affected by GPS-jamming of aircrafts, these are the first confirmed surface effects. Reason unknown.

The official reports are from NAVTEX warnings, published last 24h.

SE report state "GPS and AIS interference seen in areas south Öland and south Baltic Sea."

From DK: Bornholm DGPS-transmitter is out of order. Those complement sat-based GPS and heightens accuracy. Not today.

The area is one of the worlds most busy shipping lanes.

The reason is so far unknown and might very well be something benign.

The Baltic Jammer in Kaliningrad is hindered by physics to be the cuplrit (unless it is spacebased, which has not been indicated.)

Besides the official reports the Marinetraffic-replay looks odd with jumpy ships. Unfortunately MT is not working as per usual so I cant record it.

There is also this report and a sailor in my DMs confirming.

Thanks to the awesome service at in a few days we will all be able to analyze what the jammed ships of Bornholm actually sent with their AIS-transponders. Here's a preview of one possible analysis method, a visual one. web.ais.dk/aisdata/

There are lots of data fields! I plan on running code that looks for unnatural speeds.
If there is a sudden speed change, and especially if it does not match the log of the ship, something is up. That's one way of finding traces of GPS-interference. Interested? Dig in!

Ship after ship reporting "NO GPS" in South Baltic Sea. Right now.

To be very clear: we have no idea why they are losing GPS. This is 24 hours fresh. It is confirmed by SE maritime authorities though.

Sailors in the area, please post data/images/videos/recordings if you encounter the South Baltic GNSS/GPS interference.

DMs are open and I am discreet if need be.