A geosynchronous earth orbiting satellite (GEOS) is
|“||a satellite placed in a geosynchronous orbit at the prescribed distance of 22,300 miles above the equator.||”|
|“||[a] satellite with a mean sidereal period of rotation about the primary body equal to the sidereal period of rotation of the primary body about its own axis. Remains in a fixed position above the primary body at 35,786km or 22,366 nautical miles.||”|
GEOS can be deployed either in a constellation (several satellites), or as a single satellite, depending on the nature of the service that they will deliver. Deployment of a constellation of GEOS in several different orbit locations can provide global communication. The system of satellites is linked by inter-satellite communications to manage the switching and administration. Interconnection with the Public Switched Telephone Network (PSTN) can be provided, and subscribers can manage their own communications through personal ground stations.
A single GEOS satellite can be equipped to aim spot beams to achieve regional communication coverage. Such systems operate much like a cellular system (each beam representing a space-deployed cell site), with switching systems analogous to the Mobile Cellular Switches (MCSs) of a ground based cellular system.