The global positioning system (navstar)

In October 1978, the third of a series of prototype navigational satellites of an entirely new design was successfully launched. By the end of the first phase (1979) there will be six of these “NAVSTAR” satellites. They constitute one piece of a major development thrust to deploy a revolutionary navigation system called the Global Positioning System (GPS), or NAVSTAR. This system, being developed by the Air Force for the joint use of al components of the Department of Defense, has been under development since 1972. The purpose of this article is to describe the system, indicate the requirements which have caused the Department of Defense to spend many millions of dollars on the development, outline how the geodetic community can potentially use it, present the test results that have been accumulated to date and finally, indicate what future plans lie in store for this new system.