Global coverage is accomplished using a sophisticated mesh network of 66 cross-linked Low Earth Orbit (LEO) satellites in polar orbits about 781 km above the earth. Iridium performs call switching in space instead of on earth so that the call path is unaffected by local earth weather conditions. Since Iridium satellites are relatively close to the earth, the call latency experienced by Iridium users is almost unnoticeable compared to the latency experienced by callers using the Inmarsat or Thuraya satellite networks that use geostationary satellites.
In 2019, the second-generation of Iridium satellites (called Iridium NEXT) entered commercial service. Iridium continues to support the 850,000 existing Iridium subscriptions on existing Iridium equipment, but Iridium NEXT satellites will support additional capabilities including Iridium Certus terminals with dramatically faster internet speeds.
The chart below compares current state-of-the-art Iridium and Inmarsat personal satellite communications equipment. The main advantage of Iridium over other important satellite networks like Inmarsat is that Iridium has global coverage pole-to-pole. Because the Iridium network uses 66 LEO satellites spread uniformly over the surface of the earth, Iridium users are able to communicate even in mountainous terrain.
Docking Stations & External Antennas
In-building command centers and maritime applications typically require a docking station and external antenna for your Iridium handheld satellite phone. Some docking stations such as the BEAM PotsDock have an RJ-11 phone port and an optional privacy handset. Docking stations can run on wall power or DC vehicle power. The satellite phone's antenna adapter will allow it to be used directly with external antennas without a docking station, which may be useful in some situations. External antennas for fixed-site buildings, land vehicles, boats, and aircraft are available including the following:
Marine Mast Antenna with 10, 20 and 30-meter antenna cables
Low-Profile Car Antenna with 5-meter cable
Dual-Mode Iridium-GPS Antenna with 6-meter cable set
Aero Patch Antenna with 15 foot cable set
Active Antenna with antenna cables up to 52 meters