On 22 June this year, off the Black Sea coast of Novorossiysk, Russia, a vessel had a problem. Its GPS system said its position was 80 percent accurate to within 100 metres, but it was actually wrong by 25 nautical miles. That’s some 46 kilometres.
According to a report at The Maritime Executive, the US Coast Guard Navigation Center told the vessel’s master that GPS in that region should be accurate down to 3 metres, and advised checking for software updates. But everything was working, and this vessel wasn’t the only one with problems.
“I confirm my GPS equipment is fine. We run self test few times and all is working good. I confirm all ships in the area (more than 20 ships) have the same problem. I personally contacted three of them via VHF, they confirmed the same,” the master messaged.
“For few days, GPS gave a position inland (near Gelendzhik airport) but vessel was actually drifting more than 25 NM from it.”
The obvious explanation is that Russia was interfering with GPS signals. Nobody has confirmed that theory, but Russia does have “very advanced capabilities to disrupt GPS”, as The Maritime Executive put it.
Todd Humphreys from the University of Texas at Austin thinks this is exactly what’s going on. “The receiver’s behaviour in the Black Sea incident was much like during the controlled attacks my team conducted,” Humphreys told New Scientist.
Similar effects have been seen in Moscow, where a fake GPS signal relocates people to Vnukovo Airport, 32 kilometres away. The problem wasn’t hugely apparent until people tried playing Pokémon Go near the Kremlin.
The theory makes sense. GPS was invented by the US to target weapons, especially nuclear-tipped cruise missiles, so why wouldn’t Russia try to break it?