====== GPS ======

  * [[https://ciechanow.ski/gps/]]
  * [[https://www.telesens.co/2017/07/17/calculating-position-from-raw-gps-data]]
  * [[https://lea.hamradio.si/~s53mv/navsats/theory.html| A homemade receiver for GPS & GLONASS satellites]] 
  * [[http://www.aholme.co.uk/GPS/Main.htm|Homemade GPS Receiver]]