via The Week
Our society relies on the “invisible utility” known as GPS,says David Hambling at the New Scientist. Cell phones, ATMs, in-car navigation systems — they all rely on satellite signals. If they were suddenly jammed, chaos could ensue. But what would it take to jam GPS signals? Roughly $30. Here, an instant guide:
How exactly does GPS work?
A global positioning system (GPS) receiver gets signals from at least four orbiting satellites, allowing it to calculate its exact location. The dominant provider of satellite signals is the U.S. military, whose NavStar network has at least 24 satellites operating at any given time.
How easy is it to disrupt a GPS signal?
Very easy. GPS signals are extremely weak — after all, they’re coming from around 12,000 miles away — so it doesn’t take a lot of energy to disrupt them. David Last, a navigation consultant, managed to jam the network of a 500-ton ship using a homemade device. When he switched it on, the ship went “haywire,” reports The New Scientist. Its navigation, radar, and communications systems all went down in a matter of minutes.