Ship's captains and outside monitoring firms have reported waves of GPS jamming around Shanghai's ports, on a scale and of a severity never seen before: the jamming causes ships' locations to be incorrectly displayed and to jump around; the observations were confirmed via an anonymized (sic) data-set from a short-hire bike firm, whose bikes are also mysteriously appearing and disappearing at locations all through the region. The spoofing has created a massive local shipping hazard and has led to spectacular shipwrecks.
The most likely culprit in the mystery is sand smugglers, who are part of a global network of sand-thieves who have literally cratered whole cities and islands in their drive to obtain sand for concrete.
Sand for Shanghai's building boom was largely dredged from the Yangtze river, so prolifically that bridges, buildings, riverbanks and ecosystems on the river collapsed. The Chinese state has banned dredging from the Yangtze, but the practice continues, and it's theorized that "soft gold" smugglers are using GPS jammers to prevent Chinese law-enforcement from detecting and interdicting their vessels.
The Shanghai "crop circles," which somehow spoof each vessel to a different false location, are something new. "I'm still puzzled by this," says Humphreys. "I can't get it to work out in the math. It's an interesting mystery." It's also a mystery that raises the possibility of potentially deadly accidents.
"Captains and pilots have become very dependent on GPS, because it has been historically very reliable," says Humphreys. "If it claims to be working, they rely on it and don't double-check it all that much."
On June 5 this year, the Run 5678, a river cargo ship, tried to overtake a smaller craft on the Huangpu, about five miles south of the Bund. The Run avoided the small ship but plowed right into the New Glory (Chinese name: Tong Yang Jingrui), a freighter heading north.
Ghost ships, crop circles, and soft gold: A GPS mystery in Shanghai [Mark Harris/Technology Review]
(via Dan Hon)