TRUE GLOBAL COMMUNICATIONS

The Iridium system is the only communications system providing true global communications coverage including oceans, and all land areas including the Poles. The Iridium system blankets the Earth, connecting global satellite coverage with local ground-based wireless services.

Iridium Satellite Network

Each Iridium satellite is cross-linked to four other satellites - two satellites in the same orbital plane and two in an adjacent plane. These links create a dynamic network in space - calls are routed among Iridium satellites without touching the ground, creating a highly secure and reliable connection. Cross-links make Iridium particularly impervious to natural disasters - such as hurricanes, tsunamis and earthquakes - that can damage ground-based wireless towers since cross-links are space-based.

The Iridium ground network is comprised of the system control segment and telephony gateways used to connect into the terrestrial telephone system. With centralized management of the Iridium network, the system control segment supplies global operational support and control services for the satellite constellation, delivers satellite tracking data to the gateways, and controls the termination of Iridium messaging services.

The system control segment consists of three primary components -- four telemetry tracking and command/control (TTAC) stations, the operational support network, and the satellite network operation center (SNOC). Ku-Band feeder links and cross-links throughout the satellite constellation supply the connections among the system control segment, the satellites and the gateways.

Gateways are the ground-based antennas and electronics that provide voice and data services, messaging, prepaid and postpaid billing services, as well as other customer services. The gateways are responsible for the support and management of mobile subscribers and the interconnection of the Iridium network to the terrestrial phone system. Gateways also provide management functions for their own network elements and links.