Russian authorities appear to be systematically messing with GPS and other GNSS signals in multiple locations, a new report from the Center for Advanced Defense Studies concludes (CBS News, Foreign Policy, Moscow Times, Wired). The tactic is called GPS spoofing: broadcasting a false GPS/GNSS signal in a specific location to fool GPS/GNSS receivers and render them unreliable or unusable. The incidents appear to correlate with sensitive Russian facilities, active combat zones, and the travel itinerary of one Vladimir V. Putin. In one case, while Putin was opening a bridge between Russia and Crimea, nearby ships were suddenly informed by their GPS/GNSS receivers that they were dozens of kilometres away from their actual position.