Iridium satellite technology, theory and frequency bands
- a tutorial and overview of the Iridium satellite phone system together with details of its history, theory, technology and frequency bands used and Iridium Next.
SATELLITE PHONE TUTORIAL INCLUDES
Communications satellite basicsCommunications satellite technologySatellite phone systemsIridium
Iridium satellite system is used to provide voice and data coverage to satellite phones, pagers and other equipment with full global coverage (including the poles). The Iridium satellite system is owned by Iridium LLC based in the USA. This corporation not only operates the satellite constellation, but also provides equipment and services.
The Iridium satellite system uses a frequency band in L band 1616 - 1626.5 MHz for communication with the users. The phone systems communicate directly with the satellite which then routes the data accordingly. The data may then be routed to other satellites or to the ground.
The Iridium satellite system uses L band transponders to communicate with the ground based users with frequencies in the band 1616 - 1626.5 MHz while the backhaul to the terrestrial gateways is in the band between 29.1 and 29.3 GHz for the up-link and in the band between 19.1 and 19.6 GHz for the downlink. Links for the inter-satellite links to are in the frequency band between 22.55 and 23.55 GHz.
The user-satellite link uses a total of 10.5 MHz starting at 1616 MHz. This provides 240 channels, each separated by 41.67 kHz. This allows for a channel bandwidth of 31.5 kHz together with a suitable guard-band to accommodate inter-modulation and Doppler shifts caused by the satellite velocity relative to the ground stations.
The Iridium satellite system offers many advantages and is currently used by many people. This satellite phone system offers full global coverage for voice and data (albeit at a low rate). It is also certified for airborne use and along with many other roles, the Iridium satellite phone system is able provide a useful service to many.