Phantom Warships
The AIS (Automatic identification system) is used (under international law) by naval vessels to broadcast and track their position on the water, to avoid collisions and aid search and rescue. The transponders on each vessel broadcast data that is detected by land based AIS stations and satellites. It turns out some AIS ground stations have been picking up phantom warships from different countries in places where they shouldn't be, the waters of other sovereign nations.
