"The TRANSIT satellite system was developed by the Applied Physics Laboratory (APL) of Johns Hopkins University for the U.S. Navy. Just days after the Soviet launch of Sputnik 1, the first man-made earth-orbiting satellite on October 4, 1957, two physicists at APL, William Guier and George Weiffenbach, found themselves in discussion about the microwave signals that would likely be emanating from the satellite. They were able to determine Sputnik's orbit by analyzing the Doppler shift of its radio signals during a single pass. Frank McClure, the chairman of APL's Research Center, suggested that if the satellite's position were known and predictable, the Doppler shift could be used to locate a receiver on Earth.
"Development of the TRANSIT system began in 1958, and a prototype satellite, Transit 1A, was launched in September 1959. That satellite failed to reach orbit. A second satellite, Transit 1B, was successfully launched April 13, 1960, by a Thor-Ablestar rocket. The first successful tests of the system were made in 1960, and the system entered Naval service in 1964" (Wikipedia article on Transit (satellite), accessed 12-26-2012).
NAVSAT was the first operational satellite navigation system. Using a constellation of five satellites, the system was primarily used to obtain accurate location information by ballistic missile submarines, and was also used as a general navigation system by the Navy, and in hydrographic and geodetic surveying. Since there was no computer small enough to fit through a submarine’s hatch, a new computer was designed, named the AN/UYK-1. It was built with rounded corners to fit through the hatch, was about five feet tall, and sealed to be water-proof.