How GPS can still work (sort of) in a tunnel

Boston Globe
GPS sleight of hand Reader Eric Wilker of Newton figured his car’s GPS would never work underground in Big Dig tunnels because it relies on a satellite feed. But during a recent trip to Logan Airport, his hand-held Garmin GPS worked the entire way, find out why

Leave a Reply

May 2017
M T W T F S S
« Jan    
1234567
891011121314
15161718192021
22232425262728
293031