The Navy Navigation Satellite System – A GPS Precursor


Satellite navigation was first described in U.S. Patent 3,172,108 (1965).

A couple of years ago, I surveyed the origins of the GPS system in a Sputnik-inspired satellite navigation system that operated using Doppler shift measurements of satellite signals. The TRANSIT or NAVSAT system yielded 100m – 400m location accuracy (accounts vary).

The system included several firsts: the first nuclear powered satellite (Transit 4A) as well as the first satellite damaged in a nuclear blast (Transit 4B damaged by the United States Starfish Prime high-altitude nuclear test in 1962).

Transit was increasingly overshadowed by the superior performance of  GPS and ceased operation in 1996.

Here’s a very informative Navy training video dating back to 1967 providing an excellent overview of the system and how it worked.

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