There is a series of 6 documentaries called "Moon Machines", each looking at one of the factors (Saturn V, Lunar Lander, Rover, Space Suits, Cammand Module, and Navigation), and the navigation one about the INS is a great watch. They are all great come to think of it, but really enjoyed the INS episode.

Amazing stuff!  Hows the size of that 'modern new computer' and that 'rope memory' would drive you crazy making that then to be told we dont need any of that anymore