![]() Similarly, should one link in this network fail, the system can recognize and quickly respond by providing alternative routing paths for the communication to reach the end users. The cross-linked satellite architecture permits Iridium to operate with increased reliability due to the inherent meshed architecture involving both celestial and terrestrial infrastructure.Back-up Earth Terminals at other locations within the teleport network architecture can allow traffic to be grounded in multiple locations.Inter Satellite Link (ISL) traffic can be routed within the constellation until a spare is moved into place.The outage will be localized to the user or region.If a single satellite is temporarily unavailable due to technical issues or planned maintenance:.The LEO satellite constellation also makes it possible for changing and multiple view angles to the satellite so that line of sight issues will be temporary as long as you have a view of the sky. The large number of fast-moving satellites with multiple overlapping spot beams minimizes missed connections and dropped calls, since more than one satellite is usually visible from any place on Earth.This architecture is unique to Iridium, and it provides inherent advantages in performance and reliability over other mobile satellite services providers: And this all happens in fractions of seconds and is completely seamless to the end user. The call is relayed from satellite to satellite around the constellation without touching ground until it is downlinked at an Iridium gateway and subsequently patched into the public switched telecommunication network (PSTN) for transmission to its destination. Thus, the satellite network – much like a cellular network – hands off voice or data communications automatically from one spot beam to another within the satellite footprint, and from one satellite to the next as they pass overhead. The network is considered a meshed constellation of interconnected, cross-linked satellites so that each satellite “talks” with the other nearby satellites in front, behind and in adjacent orbits. All spot beams and satellite footprints overlap. The size of each spot beam is approximately 250 miles in diameter and the satellite’s full 48-beam footprint is approximately 2,800 miles in diameter. It is a function of latitude/longitude and beam coverage, but it typically takes about ten minutes for a satellite to cross the sky from horizon to horizon.Įach satellite can project 48 spot beams on the Earth’s surface. The low-flying satellites travel at approximately 17,000 miles per hour, completing an orbit of the Earth in about 100 minutes. There are 11 satellites in each of six orbital planes and their orbits “crisscross” roughly over the north and south poles. The satellites operate in near-circular low-Earth orbits (LEO) about 780 km (483 miles) above the Earth’s surface. Iridium’s constellation consists of 66 cross-linked operational satellites, plus six in-orbit spares. ![]() The satellites are the towers, orbiting the Earth and handing off calls to each other as they pass overhead. Iridium’s satellite network functions in much the same way. As you move from one cell to another, the system automatically hands off your call seamlessly to the next tower. ![]() Most of us are familiar with the way mobile phone networks work, with multiple interconnected cellular towers. ![]()
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