Here's gps from another perspective: http://lea.hamradio.si/~s53mv/navsats/theory.html http://lea.hamradio.si/~s53mv/navsats/theory.html This guy made his own

Here's gps from another perspective: http://lea.hamradio.si/~s53mv/navsats/theory.html http://lea.hamradio.si/~s53mv/navsats/theory.html This guy made his own gps receiver from scratch in 1991-1992