From minitrack to NAVSTAR: The early development of the Global Positioning System, 1955–1975

Summary form only given, as follows. The paper focuses on the work of the Naval Research Laboratory on systems that contributed to the later Global Positioning System. NRL´s contributions include the Minitrack system for space surveillance, the development of high-precision timing systems for use in space, the Timation navigation satellite program, and the first two Navigation Technology Satellites. When NAVSTAR-GPS emerged in 1973, much of the GPS concept had been developed and a number of GPS technologies had been tested.