The Iridium System – How it Works

The Iridium system is changing the way the world communicates as the first truly global, personal, satellite-based telecommunications system providing communications via hand-held wireless telephones and pagers. It will revolutionize communications for business professionals, travelers, residents of rural or undeveloped areas, disaster relief teams, and others who need the features and convenience of a wireless hand-held telephone with a single worldwide number.

Subscribers will use hand-held Iridium telephones transmitting through digital facilities to communicate with any other telephone in the world. Explore the new world of Iridium and find how to change your way to communicate!

How the System Works

When an Iridium telephone is activated, the nearest satellite – in conjunction with the Iridium network – automatically determines account validity and the location of the user. The subscriber selects among cellular or satellite transmission alternatives, depending on compatibility and system availability, to dispatch a call.

If the subscriber’s local cellular system is unavailable, the telephone communicates directly with a satellite overhead. The call then is transferred from satellite to satellite through the network to its destination, either to another Iridium telephone or to an Iridium ground station. Iridium system gateways interconnect the satellite network with land-based fixed or wireless infrastructures worldwide.

Quality communications is ensured by the Iridium system’s space segment, which includes a constellation of 66 satellites located 780 kilometres (420 nautical miles) above the Earth’s surface. Compared to geostationary communications satellites located 35,900 kilometres (22,300 nautical miles) above the Earth, the low earth orbit of Iridium satellites allows more tightly focused beams to be projected on the ground, providing transmissions that are clear and strong.

The system is structured like an atom with the Earth as a nucleus and the satellites as electrons. The receiving antenna is small enough to fit on a hand-held telephone. The small, lightweight Iridium satellites are electronically interconnected to provide continuous worldwide coverage. Communications are relayed via satellite and through terrestrial gateways, where billing information and user location data will be stored.

Intersatellite and ground control links take place in the Ka-band frequencies. Telephone and messaging communications take place in the L-band frequencies.

Services within various countries are provided through telecommunications authorities and local service providers.

References

Iridium – How it works. (n.d.). Retrieved June 02, 2016, from https://geoborders.com/iridium/en/iridium.htm