ACARS via Iridium
Iridium is a large satellite constellation that consists of 66 low-earth orbiting (LEO), cross-linked satellites operating as a fully meshed network providing truly global coverage (including oceans, airways and polar regions). Iridium satellites are in a near-polar orbit at an altitude of 485 miles. The network is composed of 66 active satellites that fly in six orbital planes, each with 11 satellites per plane. Satellites circle the earth once every 100 minutes. ACARS is an Aircraft Communication Addressing and Reporting System otherwise known as Digital DataLink System. ACARS was first developed in the 1970’s. It is a point-to-point service that either sends air-to-ground messages or receives ground-to-air messages from the cockpit. ACARS via Iridium now gives Flight Departments the capability to communicate with the aircraft in their fleet all over the globe. ACARS is now a viable option via Iridium. Until now ACARS was only available by 2 different mediums. ACARS via Very High Frequency (VHF) communication is only available through line of site. ACARS via Inmarsat (Satcom) is only available over the populated continents and does not provide communications over polar routes. The cost of Iridium service is far less than that of Satcom and is available over oceans whereas VHF is not. This allows aircraft to access various services provided by ACARS Service Providers.
Aircraft can now send a number of automatic reports (OOOI, engine oil pressure, position reports, fuel, and etc) using ACARS via Iridium. Pilots can request relevant information pertaining to flight safety and receive necessary in-flight updates. Some of the data services include: Text-based and Graphical Weather, Flight Planning and Clearances, Text Messaging, Position Reporting, Automatic Terminal Information Services (ATIS), Terminal Weather Information for Pilots (TWIP), and OOOI messages (Out of the gate, Off the ground, On the ground, and Into the gate)....
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