Limitations of these systems drove the need for a more universal navigation solution with greater accuracy.
While there were wide needs for accurate navigation in military and civilian sectors, almost none of those was seen as justification for the billions of dollars it would cost in research, development, deployment, and operation for a constellation of navigation satellites.
Satellites are relay stations in space for the transmission of voice, video and data communications.
They are ideally suited to meet the global communications requirements of military, government and commercial organizations because they provide economical, scalable and highly reliable transmission services that easily reach multiple sites over vast geographic areas.
In addition to geostationary spacecraft, a few commercial satellite communications systems operate from low Earth orbits (typically several hundred miles above Earth).
The lower orbit significantly reduces the delay that is created as the signal travels between Earth and the satellite.
integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s. It was initially developed for use by the United States military and became fully operational in 1995. When the Soviet Union launched the first artificial satellite (Sputnik 1) in 1957, two American physicists, William Guier and George Weiffenbach, at Johns Hopkins University's Applied Physics Laboratory (APL) decided to monitor its radio transmissions.
As a result, a number of countries have developed or are in the process of setting up other global or regional navigation systems.In addition, the satellite’s antennas direct the signal over a specific geographic area.