A satellite phone or satphone is a mobile phone that communicates directly with orbiting satellites. Depending on the architecture of a particular system, coverage may include the entire planet, or only specific regions.
The mobile equipment, also known as a terminal or earth station, varies widely. A satellite phone handset has a size and weight comparable to that of a late 1980s or early 1990s cell phone, but with a large retractable antenna. These are popular on expeditions into remote areas where terrestrial cellular service is unavailable.
A fixed installation, such as used shipboard, may include large, rugged, rack-mounted electronics, and a steerable microwave antenna on the mast that automatically tracks the overhead satellites.
Low Earth orbit
LEO telephones utilizes LEO (low Earth orbit) satellite technology. The advantages include providing worldwide wireless coverage with no gaps. All satellite phones tend to be LEOs. LEO satellites orbit the earth at high speed, low altitude orbits with an orbital time of 70–90 minutes, an altitude of 400–700 miles, and provide coverage cells. Since the satellites are not geosynchronous, they must fly complete orbits and thus further guarantee complete coverage over every area by at least one satellite at all times. Blimps are being considered as satellites.
See also
Last updated: 10-17-2005 17:22:29
