Sat Nav has revolutionised navigation, bringing military grade satellite positioning to the consumer. But how does it work? James May steers us through the science of Sat Navs in this Headsqueeze video. Subscribe for more fascinating science videos: http://bit.ly/SubscribeToEarthLab

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James May's Q&A
With his own unique spin, James May asks and answers the oddball questions we've all wondered about from 'What Exactly Is One Second?' to 'Is Invisibility Possible?'

Welcome to BBC Earth Science! Here we answer all your curious questions about science in the world around you. If there’s a question you have that we haven’t yet answered let us know in the comments on any of our videos and it could be answered by one of our Earth Science experts.