Here is a film produced in the 1950s by the U.S. Air Force describing Project SPIRE (Space Inertial Reference Equipment), which demonstrated inertial guidance on a U.S. coast-to-coast flight in a B-29 bomber. The inertial guidance system operation and construction is described in great detail.
Last week I was talking to an old PLATO colleague whose mentioned his father worked on the first nuclear submarine inertial guidance system that used, of all things, an electrically levitated sphere:
Item History: Inertial navigation systems based on the electrically suspended gyroscope (ESG) have proven to be, over the last thirty three years, the most accurate implementation of inertial navigation. The history of the ESG dates back to the definition of the ESG concept by Professor Arnold Nordsieck of the University of Illinois in 1954.