Inmarsat
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Inmarsat plc is an international telecommunications company founded in 1979, originally as an intergovernmental organization. It operates a fleet of eleven (as of 2005) geosynchronous telecommunications satellites. The company is publicly traded on the London Stock Exchange (LSE: ISAT) as of June 2005. It is a constituent of the FTSE 250 Index.
Inmarsat provides telephony and data services to users world-wide, via special digital radios called "terminals". An Inmarsat terminal contacts the satellite and communicates to a ground station through the satellite. It provides reliable communications services to a range of governments, aid agencies, media outlets and businesses needing to communicate in remote regions or where there is no reliable terrestrial network.
Aside from its commercial services, Inmarsat provides global 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 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 BGAN IP satellite modem the size of a notebook computer. Other services provide mobile ISDN services used by the media for live reporting on world events via videophone.
Historically expensive, calls via Inmarsat have 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 wherever in the world the service is used.
Newer Inmarsat services using IP technology feature an always-on capability where the users are simply charged for the amount of data they send and receive rather than the length of time they are online. This applies specifically to BGAN, Regional BGAN, and MPDS.
The satellites are digital transponders that receive digital signals, reform the pulses, and then retransmit them to ground stations. The ground stations perform billing and act as gateways to the public switched telephone network and Internet.
Inmarsat's most recent series of satellites were launched in June and November 2005. These were the largest commercial telecommunications satellites ever launched. Each satellite is equipped with a global beam, 19 regional spot beams, and 228 narrow spot beams.
In addition to her own satellites, Inmarsat has a collaboration agreement with ACeS regarding handheld voice services.
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[edit] Coverage
There are 3 types of coverage related to each Inmarsat satellite.
- Global beam coverage. Each satellite is equipped with a single global beam that covers up to one-third of the Earth's surface, apart from the poles. In general, global beam coverage extends from latitudes of −78 to +78 degrees regardless of longitude.
- Wide spot beam coverage. It relates to the overlap of the wide spot beams (a set of narrower beams creating a coverage pattern). Wide spot beam coverage is optimised for covering most areas of interest to Inmarsat's customers and is thus somewhat limited in comparison to global beam coverage. This coverage was introduced with the I-3 satellites. Each I-4 satellite provides 19 wide spot beams.
- Narrow spot beam coverage. It relates to the overlap of the narrow spot beams (a set of very narrow beams creating a coverage pattern). Narrow spot beam coverage is designed to form the backbone of Inmarsat's future broadband services, including the Broadband Global Area Network (BGAN). This coverage is introduced with the I-4 satellites. Each I-4 satellite provides 228 narrow spot beams.
[edit] Satellites
[edit] Inmarsat-4 satellites
- Inmarsat-4F1 / Coverage: IOR / 64 degrees East longitude / Launched on an Atlas rocket on 11 March 2005. This satellite suppports BGAN and Regional BGAN services only.
- Inmarsat-4 F2 / Coverage: AOR-West / 53 degrees West Longitude / Launched on a Sea-Launch rocket 8 November 2005 14:07 GMT. This satellite supports nearly all Inmarsat services.
- Inmarsat-4 F3 has been completed and is awaiting launch.
[edit] Inmarsat-3 satellites
- Inmarsat-3F1 / Coverage: IOR / 65 degrees East longitude / Launched with Atlas Centaur IIA on 3 April 1996. This satellite is used for existing and evolved services only.
- Inmarsat-3F2 / Coverage: AOR-E / 15.5 degrees West longitude / Launched with Proton D-1-E on 6 September 1996. This satellite is used for existing and evolved services only.
- Inmarsat-3F3 / Coverage: POR / 178 degrees East longitude / Launched with Atlas Centaur IIA on 17 December 1996. This satellite is used for existing and evolved services only.
- Inmarsat-3F4 / Coverage: PAC-C / 142 degrees West longitude / Launched with Ariane 4 (V97) on 3 June 1997. This satellite is used for various leases.
- Inmarsat-3F5 / Spare (AOR-W) / 54 degrees West longitude / Launched with Ariane 4 (V105) on 4 February 1998.
[edit] Inmarsat-2 satellites
These satellites are primarily used for leases.
- Inmarsat-2F1, launched October 1990, expected operational life 2010
- Inmarsat-2F2, launched March 1991, expected operational life 2010
- Inmarsat-2F3, launched December 1991, decommissioned 2006
- Inmarsat-2F4, launched April 1992, expected operational life 2016
[edit] Country codes
The telephone country codes for calling Inmarsat destinations are:
- 870 SNAC (Single Network Access Code)
- 871 Atlantic Ocean Region – East (AOR-E)
- 872 Pacific Ocean Region (POR)
- 873 Indian Ocean Region (IOR)
- 874 Atlantic Ocean Region – West (AOR-W)
The 870 SNAC number is actually a locator service so that you don't have to know to which satellite the destination Inmarsat terminal is logged in. SNAC however doesn't support calls to Inmarsat-A terminals.
The other four country codes correspond to the areas which Inmarsat satellites cover (normally one satellite per area). These areas are commonly called "Ocean Regions".
[edit] Networks
Inmarsat has gradually developed a series of networks providing certain sets of services (most networks support multiple services). They are grouped into two sets, existing and evolved services, and IP-based services. Existing and evolved services are offered through Land Earth Stations which are not owned nor operated by Inmarsat, but through companies which have a commercial agreement with Inmarsat. IP-based services are provided via distribution partners but the satellite gateways are owned and operated by Inmarsat directly.
IP-based shared-carrier services, as follows:
- Regional BGAN: RBGAN offers a shared-channel IP packet-switched service of up to 144 kbit/s based on GPRS technology. Coverage is limited to parts of Europe, Asia, Africa & Australia. The new Inmarsat-4 satellite for the Indian Ocean Region (IOR) has taken over RBGAN service from the Thuraya satellite. The new Inmarsat-4 satellite for AOR-West now provides service to South America and the Western edges of Europe and Africa, however no service is offered to North or Central America. Inmarsat have announced the closure of the RBGAN service on December 31, 2008.
- BGAN: Broadband Global Area Network (BGAN) benefits from the new I-4 satellites to offer a shared-channel IP packet-switched service of up to 492 kbit/s (uplink and downlink speeds may differ and depend on terminal model) and a streaming-IP service from 32 up to 256 kbit/s (services depend on terminal model). Certain terminals also offer circuit-switched Mobile ISDN services at 64 kbit/s and even low speed (4.8 kbit/s) voice etc services. BGAN service is available on the IOR satellite and AOR-West satellite, with POR service planned for 2007. The BGAN family includes SwiftBroadband, a service planned for aircraft, and FleetBroadband, a service planned for ships and the maritime community.
Historic services, termed "Existing and Evolved", as follows:
- Inmarsat-A: provides voice services, telex services, medium speed fax/data services and, optionaly, high speed data services at 56 or 64 kbit/s. This is the only analog network of Inmarsat and is scheduled for phase-out by 31 December 2007. The rest of the Networks are digital and no phase-out date is currently available. The Inmarsat-A service on IOR has been moved to a backup satellite at 109 degrees East longitude due to the use of the new Inmarsat-4 satellite for the primary IOR coverage. The Inmarsat-A service on AOR-West has been moved to a backup satellite at 98 degrees West longitude due to the use of the new Inmarsat-4 satellite for the primary AOR-West coverage.
- Aeronautical (Classic Aero): provides voice/fax/data services for aircraft. Three levels of terminals, Aero-L (Low Gain Antenna) primarily for packet data including ACARS and ADS, Aero-H (High Gain Antenna) for medium quality voice and fax/data at up to 9600 bit/s, and Aero-I (Intermediate Gain Antenna) for low quality voice and fax/data at up to 2400 bit/s. Note, there are also aircraft rated versions of Inmarsat-C and mini-M/M4. The aircraft version of GAN is called Swift64 (below)
- Inmarsat-B: provides voice services, telex services, medium speed fax/data services at 9.6 kbit/s and high speed data services at 56, 64 or 128 kbit/s. There is also a 'leased' mode for Inmarsat-B available on the spare Inmarsat satellites.
- Inmarsat-C: effectively this is a "satellite telex" terminal with store-and-forward, polling etc capabilities. Certain models of Inmarsat-C terminals are also approved for usage in the GMDSS system, equipped with GPS.
- Inmarsat-M: provides voice services at 4.8 kbit/s and medium speed fax/data services at 2.4 kbit/s. It paved the way towards Inmarsat-Mini-M.
- Mini-M: provides voice services at 4.8 kbit/s and medium speed fax/data services at 2.4 kbit/s. Uses Inmarsat's zonal ray technology
- GAN (Global Area Network): provides a selection of low speed services like voice at 4.8 kbit/s, fax & data at 2.4 kbit/s, ISDN like services at 64 kbit/s (called Mobile ISDN) and shared-channel IP packet-switched data services at 64 kbit/s (called Mobile Packet Data Service MPDS, formerly Inmarsat Packet Data Service – IPDS). GAN is also known as known as "M4".
- Fleet: actually a family of networks that includes the Inmarsat-Fleet77, Inmarsat-Fleet55 and Inmarsat-Fleet33 members. Much like GAN, it provides a selection of low speed services like voice at 4.8 kbit/s, fax/data at 2.4 kbit/s, medium speed services like fax/data at 9.6 kbit/s, ISDN like services at 64 kbit/s (called Mobile ISDN) and shared-channel IP packet-switched data services at 64 kbit/s (called Mobile Packet Data Service MPDS). However, not all these services are available with all members of the family. The latest service to be supported is Mobile ISDN at 128 kbit/s on Inmarsat-Fleet77 terminals.
- Swift 64: Similar to GAN, providing voice, low rate fax/data, 64kb/s ISDN, and MPDS services, for private, business, and commercial aircraft. Swift 64 is often sold in a multi-channel version, to support several times 64kb/s.
- Inmarsat-D/D+: Inmarsat's version of a pager, although much larger than terrestrial versions. Some units are equipped with GPS. The original Inmarsat-D terminals were one-way (to mobile) pagers. The newer Inmarsat-D+ terminals are the equivalent of a two-way pager. The main use of this technology nowadays is in tracking trucks and buoys and SCADA applications. Inmarsat D+ is the only GPS tracking service available via Inmarsat. Competing systems such as from Skybitz only operate on the MSAT geostationary satellite over North America.
- Inmarsat-E: A global maritime distress alerting service using small Emergency Position Indicating Rescue Beacons (EPIRB) that automatically send message to maritime Rescue Coordination Centres. This service was terminated in 2006 in agreement and coordination with the IMO and IMSO, and is no longer available. Inmarsat moved all users to the 406 MHz system, an equivalent EPIRB working via Cospas-Sarsat satellites, when the Inmarsat-E service was switched off in 2006. The service was terminated due to lack of interest from the maritime community.
- MPDS (Mobile Packet Data Service): Previously known as IPDS, this is an IP-based data service in which several users share a 64kb/s carrier in a manner similar to ADSL. MPDS-specific terminals are not sold; rather, this is a service which comes with most terminals that are designed for GAN, Fleet, and Swift64.
Handheld Voice Services are anticipated under a collaboration agreement with ACeS.
[edit] History
Inmarsat was originally founded as the International Maritime Satellite Organization as a not-for-profit international organization in 1979, at the behest of the International Maritime Organization ("IMO", a UN body) for the purpose of establishing a satellite communications network for the maritime community. From the beginning the acronym "Inmarsat" was used. The intent was to create a self-financing body which would improve safety of life at sea. The name was changed to International Mobile Satellite Organization when it began to provide services to aircraft and portable users, but the acronym "Inmarsat" was kept. When the organization was corporatized, the company was split into two parts: the bulk of the organization was converted into the commercial company Inmarsat plc, and a small group became the regulatory body IMSO. In spite of the commercial structure, Inmarsat has maintained its traditional multicultural atmosphere of some 45 nationalities in the London headquarters. Inmarsat continues to ensure it meets the requirements of a Global Maritime Distress and Safety System (GMDSS) as established by the IMO.
Inmarsat has been based in London throughout its history, where the vast majority of its 400 staff are located.
In 1982 Inmarsat established the Standard-A (later to become Inmarsat-A) satellite communications system for ships, based on a system developed in the mid-1970s by Comsat. It initially used leased transponders on three satellites (AORE, IOR, and POR), and offered priority communications for emergency and distress. By the end of 1986 there were 3800 Standard-A users. The customer base increased approximately 100-fold in the next 20 years.
[edit] See also
- ACeS
- telephone
- marine and mobile radio telephony
- Intelsat
- Iridium
- Globalstar
- Thuraya
- IMSO
- International Maritime Organization
