Which of the following is not used for voice communication.
GPS is not used for voice communication.
An early satellite-based system dubbed TRANSIT was up and running as early as 1960, with more refined and precise versions involving multiple satellites in general military use by the early 1980s (pictured, right). But it wasn't until 2000 that precision GPS navigation became open to the public.
The Global Positioning System (GPS) is a network of about 30 satellites orbiting the Earth at an altitude of 20,000 km. ... Once it has information on how far away at least three satellites are, your GPS receiver can pinpoint your location using a process called trilateration.
During Labor Day weekend in 1973, a meeting of about twelve military officers at the Pentagon discussed the creation of a Defense Navigation Satellite System (DNSS). It was at this meeting that the real synthesis that became GPS was created.
GPS (or global positioning system), is a satellite-based navigation system made up of a network of 24 satellites orbiting the earth at all times. This system, when the proper signals are received, allows a user to tell where they are located.