Although the American ship’s GPS signals initially seemed to have just been jammed, both it and its neighbor had also been spoofed—their true position and speed replaced by false coordinates broadcast from the ground. This is serious, as 50% of all casualties at sea are linked to navigational mistakes that cause collisions or groundings.
When mariners simply lose a GPS signal, they can fall back on paper charts, radar, and visual navigation. But if a ship’s GPS signal is spoofed, its captain—and any nearby vessels tracking it via AIS— will be told that the ship is somewhere else entirely.
After receiving the tip, C4ADS looked at the AIS data, which it purchased from a startup that records AIS broadcasts around the world. Analysts noticed that the attacks had actually started the previous summer, increasing as the months rolled on. The most intense interference was recorded on the very day in July that the Manukai’s captain reported difficulties, when a total of nearly 300 vessels had their locations spoofed. While the disruption was affecting ships right across Shanghai, most of those spoofed were vessels navigating the Huangpu River.
And this was very different from the hacking seen in Russian waters, where vessels were all spoofed to a single point. The Shanghai data showed ships jumping every few minutes to different locations on rings on the eastern bank of the Huangpu. On a visualization of the data spanning days and weeks, the ships appeared to congregate in large circles.