GPS Selective Availability switched off (2000)
For years the US military deliberately degraded civilian GPS accuracy, a feature called Selective Availability, to blur precision for potential adversaries. In May 2000 the US turned it off, instantly sharpening civilian positioning worldwide.
Civilian GPS accuracy improved roughly tenfold overnight, spurring consumer navigation and mapping products.
The episode reminded other governments that a single country controlled the switch on a service the world depended on.
It is the clearest example of why nations build their own systems. Whoever owns the satellites can dial the signal up or down, and Japan wanted that control at home.
