Intermediate circular orbit
Intermediate circular orbit (ICO), also called medium earth orbit (MEO), is used by satellites between the altitudes of low earth orbit (up to 1400 km) and geostationary orbit (ca. 36,000 km). GPS uses a MEO satellite constellation.
A number of telecommunications systems have been proposed using MEO satellite constellations.
ICO was also the name of a proposed communications constellation for satellite telephony, originally developed by Inmarsat and spun off. In the wake of the financial failure of the Iridium satellite constellation, ICO also entered bankruptcy protection and delayed launching its satellites.
A third proposed system was Teledesic.Medium earth orbit communications systems
