How the GPS was invented 

#GPS   #Post
In 1957, the  Sputnik 1  was launched and it become the first artificial satellite in orbit. 
All physics nerds were excited. Guier and Weiffenbach from the Applied Physics Lab at Johns Hopkins University were talking when one of them said: Has anyone tried to listen to the signal that the Sputnik is broadcasting? Someone in the lab had an antenna so they started to do it. 
More and more people started to go to the lab to listen to the signal and they started to write down the timestamp of the beeps of the signal. 
They noticed that the frequency was changing and one of them thought about calculating its speed using the  Doppler Effect
They talked to more people at the university coffee shop and someone else suggested that they could calculate the trajectory of the satellite. They started to do it despite the fact that they had to use their new room-size computer. 
After three or four weeks, they had mapped the trajectory just by listening to the signal. 
He was working on calculating the trajectory of missiles launched from submarines. It was tricky to guide the missiles because they didn't know the exact position of the submarines. And the GPS was conceived. 
In 1973, the satellites were launched for military use. Later, the platform was opened to civilian use and nowadays most of us use it to guide us to places; for example on Google Maps. 
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