INMARSAT

Inmarsat, abbreviation for the International Mobile Satellite Organization, which was formed by a convention of the International Maritime Organization in 1975, and began operations in 1982. Inmarsat's obligations to provide maritime distress and safety services via satellite were part of the 1988 amendments to the International Convention for the Safety of Life at Sea (SOLAS) which introduced the Global Maritime Distress and Safety System. In 1999 Inmarsat was privatized and the new structure comprises Inmarsat Ltd., a public limited company, and the International Mobile Satellite Organization (IMSO), an intergovernmental body that ensures its commercial arm continues to meet its public service obligations.

Inmarsat's four satellites provide communications for the four ocean areas except the extreme polar regions. It has various mobile systems (Inmarsat-A, -B, etc.) which provide different facilities for mariners and other users. They include direct-dial telephone, fax, e-mail, and data communications, and provide for the transmission and reception of high-quality photographs and video film. Some can be connected to satellite navigation devices such as GPS, and meet the long-range communications requirements of the Global Maritime Distress and Safety System. Inmarsat-E is currently (2004) an alternative system for alerting life saving services through L-band EPIRBs.

Aside from its commercial services, Inmarsat provides global maritime distress and safety services (GMDSS) to ships and aircraft at no charge, as a public service.

Services include traditional voice calls, low-level data tracking systems, and high-speed Internet and other data services as well as distress and safety services. The most recent of these provides GPRS-type services at up to 492 kbit/s via the Broadband Global Area Network (BGAN) IP satellite modem the size of a notebook computer. Other services provide mobile Integrated Services Digital Network (ISDN) services used by the media for live reporting on world events via videophone.

The price of a call via Inmarsat has now dropped to a level where they are comparable, and in many cases favorable, to international roaming costs, or hotel phone calls. Voice call charges are the same for any location in the world where the service is used. Tariffs for calls to Inmarsat country codes vary, depending on the country in which they are placed. Inmarsat primarily uses country code 870 (see below).

Newer Inmarsat services use an IP technology that features an always-on capability where the users are only charged for the amount of data they send and receive, rather than the length of time they are connected. This applies specifically to BGAN and MPDS.

The satellites are digital transponders that receive digital signals, reform the pulses, and then retransmit them to ground stations. Ground stations maintain usage and billing data and function as gateways to the public switched telephone network and the Internet.

The first (F1) and second (F2) of Inmarsat's most recent series of satellites, known as the "I4" satellites, were launched in June and November 2005. The third and final satellite (F3) was launched from the Cosmodrome in Kazakhstan on the 18 August 2008. These were the largest commercial telecommunications satellites ever launched. Each satellite is equipped with a global beam, 19 regional spot beams, and over 200 narrow spot beams.

In addition to its own satellites, Inmarsat has a collaboration agreement with ACeS regarding handheld voice services.