Abstract
This research note runs on from the note published by the author in this issue of IJMH. It describes the development of Maritime Satellite Communications (MSC) systems for all type of commercial and military seagoing and inland sailing vessels since the 1970s. The main functions of MSC systems are to enhance the safety and security of seagoing vessels, mainly by alerting and Search and Rescue (SAR) operations, and to improve communication facilities between ships and shore infrastructures. The first MSC Geostationary Earth Orbit (GEO) system for military applications was developed in 1976 by the US and other partners, which soon became available for merchant ships. The next step was the development of an independent and international MSC system. To overcome the disadvantages associated with HF/VHF radio propagation and frequency congestions, the International Maritime Organization (IMO) in 1979 encouraged all member nations to establish Maritime Mobile Satellite Communication (MMSC) systems. At the behest of IMO and United Nations (UN) Maritime Body, and pursuant to the Convention on the International Maritime Satellite Organization, signed by 28 countries in 1976, the International Maritime Satellite (INMARSAT) Organization was founded.
The development of the Maritime Mobile Satellite Communications (MMSC) system is de facto the history of Inmarsat and its predecessor Marisat system. These systems improved traditional maritime radio communications on MF, HF and VFH-bands, as well as enhancing distress and safety communications at sea and on inland waters. The MMSC system also provides shipping with a commercial mobile satellite communication service between vessels and infrastructures ashore. In fact, the MMSC service is two-way satellite communication between Ship Earth Stations (SES) and Coast Earth Stations (CES) via Geostationary Earth Orbit (GEO) and Non-GEO satellite constellations connecting seaports, shipowners, shippers, agents, shipping companies, and seafarers’ families. The MMSC service is used by Survival Craft Stations, Search and Rescue (SAR) vessels, Emergency Position Indicating Radio Beacon (EPIRB) alert stations and interactive ship in distress communication with CES terminals and SAR forces. The EPIRB station alerts SAR services in the event of an emergency at sea. It does this by transmitting a coded message on the 406 MHz distress frequencies via satellite and CES terminals stations to the nearest rescue co-ordination centre as part of the Global Maritime Distress and Safety System (GMDSS) and Cospas-Sarsat system. 1
The initial phase of MMSC service began with the introduction by the US of the Marisat system in 1976, satisfying a commitment made by Communications Satellite Corporation (COMSAT) in 1973 to provide a maritime satellite service. The Marisat Consortium, spun off by COMSAT, launched three GEO satellites in 1973; one to serve shipping in the Atlantic, one for the Pacific, and the third as a spare. The spare was subsequently positioned over the Indian Ocean so that the three provided almost global coverage. Superseding the limited Marisat system, Inmarsat was established in July 1979 and officially started in service on 1 February 1982 by providing a MMSC service through a system of Marecs, Intelsat-V, and Marisat satellites. Subsequently, non-GEO personal satellite systems, such as Iridium, Globalstar, and Orbcomm, were constructed to serve MMSC.
Maritime Mobile Satellite Service (MMSS)
The MMSS is a service in which SES is located on board merchant or military ships, other floating objects, rigs, or offshore constructions, hovercrafts and/or survival craft stations to deliver commercial, determination, logistic, tactical, defense and safety communications. In addition, the special maritime EPIRB terminal, either portable or fixed stations on board oceangoing ships, may also contribute to this service. The EPIRB is a special Earth station in the MMSS, the emissions of which are intended to facilitate urgent SAR operation for vessels in distress. The EPIRB unit also provides passengers and crew members with ship-to-shore communication facilities.
The MMSS communication service enables mobile satellite links between CES and SES terminals, between two or more SES and/or between associated ships and other satellite communications stations in all positions at sea or in ports. The SES is a mobile Earth station (MES) in the MMSS capable of surface movement at sea within the geographical limits of a country or continent. In contrast to conventional maritime communications, a ship fitted with SES in or near a port may operate with CES or other SES in cases of distress and commercial operations. The CES is a maritime Earth station located at a specified fixed point on the coast to provide a feeder link for MMSS. The SES is a maritime Earth station fixed on board ships or other floating objects, which can provide communications links with subscribers onshore via CES and communications spacecraft.
The ship on scene radio communications and alert service performs a distress and safety service in the MMSS between one or more SES and CES, or between two or more nearby SES, or between SES and RCC, or between portable or floating EPIRB and Local User Terminal (LUT) stations in which alert messages support those concerned with the movement and position of ships, and of ships in distress. The first-class two-way MMSC is essential for mariners to contact and constantly exchange information between vessels, owners, agents, shippers, port authorities, families, and friends, or to deal with emergencies, distress, and rescue situations at sea. Navy ships can use these facilities for fleet defence, tactical, emergency, and information purposes. Therefore, shippers will be nearer to their fleet units, using not only commercial MMSC, but also reliable distress alerting and inter-ship communications and will also have important 24-hour Maritime Safety Information (MSI), such as Weather (WX) and Navigation Warning (NX).
International coordination and Rrgulatory organizations
International coordination and regulation of the MMSC service are the responsibility of the International Telecommunications Union (ITU) and International Maritime Organization (IMO).
The ITU is organized by the UN, with all member governments contributing to the international coordination and regulation of mobile radio and satellite communications through the ITU Radio Regulations (RR). The ITU was inaugurated in 1932 and reorganized in 1992, with its head office, all committees, and departments located in Geneva, Switzerland. All of the numerous provisions of the telecommunication services applicable or useful to all stations have been defined and introduced by the general RR articles and manual on mobile radio service in a special manual for use by the Maritime Mobile and Maritime Mobile-Satellite Services. The ITU also publishes many lists of recommendations concerning RR, radiocommunications, and other technical publications. The administrative structures established by the ITU Convention comprise a secretariat headed by the Secretary General, an administrative council, registration board for RF, and consultative committees for radio and telecommunications. The entire terminology, definition of radio and satellite services, technical standards, and working frequency allocations are defined in the RR and drafted by the World Administrative Radio Conference (WARC) of the ITU.
The service, regulations, and agreements of the Maritime Safety Committee regarding distress and safety at sea are provided by the IMO. It consists of an assembly, a council and four main committees: Maritime Safety; Marine Environment Protection; Legal; and Technical Cooperation. There is also the Facilitation Committee and a number of sub-committees, which support the work of the main technical committees. Since its establishment in 1959, IMO and all of its member governments have striven to enhance the International Convention for the Safety of Life at Sea (SOLAS, 1974). In 1972, IMO, with the assistance of International Radio Consultative Committee or in French Comité Consultatif International des Radiocommunications (CCIR), commenced a study of satellite communications systems, which resulted in the establishment, in 1979, of the Inmarsat Organization. With the continuing support of CCIR, ITU, World Meteorological Organization (WMO), International Hydrographic Organization (IHO), Cospas-Sarsat, and Inmarsat, IMO has developed the Global Maritime Distress and Safety System (GMDSS), which came into force in early 1999, following almost 30 years of careful preparation.
International satellite communications organizations and operators
The main international satellite communications organizations and operators serving MMSC are Intelsat, Inmarsat, Intersputnik, and other global, multinational, or intergovernmental operators serving outside domestic and regional boundaries.
Intelsat
The Fixed Satellite Communication (FSC) systems were the first to develop and there was rapid recognition that these new global possibilities necessitated the creation of some kind of international organization. This led to the creation of the Intelsat international organization based in Washington. On 20 August 1964, 11 countries signed a charter agreement creating Intelsat, the first open worldwide satellite communications network, and appointed the Comsat Corporation as its first manager. However, Comsat placed a contract for a GEO and the Intelsat fixed system started to offer transatlantic satellite services in 1965 after the successful deployment of Intelsat I (formerly Early Bird), the world’s first GEO spacecraft.
As well as MMSC, the Intelsat operator provided services using payloads carried by the GEO spacecraft Intelsat V MCS series: A (F5), B (G6), C (F7), and D (F8). The Inmarsat organization leased capacity on Intelsat V MCS flights F5–F8 for MMSS.
These four satellites used portions of the L-band (from 0.5 to 1.7 GHz) and C-band assigned for such purposes by the International Telecommunication Union (ITU). The Intelsat V MCS A (F5) was launched on 28 September 1982 over the Indian Ocean Region (IOR) in orbital location at 63oE, while the Intelsat V MCS B (F6) was launched on 19 May 1983 over the Atlantic Ocean Region (AOR) in orbital location at 18.5°W. The Intelsat V MCS C (F7) was launched on 19 October 1983 as a spare spacecraft over IOR in orbital location at 66°E and the Intelsat MCS V D (F8) spacecraft was launched on 3 March 1984 over Pacific Ocean Region (POR) in orbital location at 53°E longitude, and relocated at the end of 1985 to the assignment of 179/180°. Thus, MCS uses radio frequencies in the top C-band transponder and an additional L-band spectrum to link CES with ships as part of the Inmarsat network. Because of the additional power requirements of the MCS packages on Intelsat V F5–F8 satellites, the Ku-band operations on these four spacecraft must be limited or curtailed when they are activated for Inmarsat use. However, when the L-band signal amplifier is operating in the high power mode, the 11 GHz Ku-band capacities of these spacecraft is switched off. These satellites after many years of service are deployed and no longer used by the Inmarsat system.
Inmarsat
The Inmarsat organization is the only international and nonmilitary MMSC operator in the world. The Inmarsat MMSC network provides voice (Tel); facsimile (fax), low, medium, and high speed data (L/M/HSD), telex (Tlx) and video (video conference and internet) service for all type of ships and sea platforms or oil rigs, as shown in Figure 1. The Inmarsat service includes modern Mobile Packet Data Service (MPDS), Integrated Services Digital Network (ISDN), LAN and IP services, and in the framework of the GMDSS system, enables distress and safety services for maritime and other mobiles including government, military, and offshore infrastructures. In addition, the MMSC system can be used for Transportable Mobile Satellite Communication (TMSC) systems with Transportable Earth Stations (TES) and Personal Mobile Satellite Communication (PMSC) using onboard ships Personal Earth Station (PES) or handheld telephone.
Inmarsat MMSC, TMSC and PMSC network infrastructure.
In the early 1970s, the IMO, then known as the Inter-Governmental Maritime Consultative Organization (IMCO), began to consider the possibility of using MMSS to improve maritime communications, not least for safety purposes. Towards the end of 1973, IMCO convened a conference to decide on the principle of establishing an international maritime safety system and to conclude the necessary agreements. The work of this conference culminated in September 1976 in the adoption of what became the Inmarsat Convention and its complementary Operating Agreement, requiring always that it works exclusively for peaceful purposes. Inmarsat was established on 16 July 1979 by the major maritime nations to finance this project, which is to investigate using satellites to form links with vessels and offshore oil rigs. Inmarsat also owes much of its success to the foresight and commitment of the IMO, which played a crucial role in its creation.
On 1 February 1982, Inmarsat officially took control of satellites previously operated by three Marisat spacecraft (series F1, F2, and F3), a joint venture among nations begun in the early 1970s through the efforts of the Comsat General. Inmarsat has since expanded its space segment by leasing additional capacity from Intelsat and the European Space Agency (ESA), Intelsat V MCS series of four spacecraft, and two Marecs spacecraft (B and B2A), respectively. However, today an additional Inmarsat second, third, fourth, fifth, and forthcoming sixth generation of GEO, Inmarsat-2, Inmarsat-3, Inmarsat-4 and Inmarsat-5 spacecraft, respectively, are being exploited.
In many ways, the Inmarsat organization is patterned after the Intelsat system and almost all countries comprise the Inmarsat Assembly as members, each country casting one vote. The Assembly meets once every two years to formulate general policy, long-term strategy, and objectives. Besides, each government selects a representative signatory to the Inmarsat Operating Agreement from the public or private sector. The Assembly also establishes financial, technical, and operational standards. The Inmarsat Council, similar to a corporate board of directors, meets three times a year to implement all policy decisions of the Assembly. The Director General of Inmarsat oversees the day-to-day management of the organization, with an executive staff based in London. Inmarsat is financed in two ways: signatories may pay fees based on their use of the network, or purchase investment shares in Inmarsat that reduce the user fees in proportion to the investment, with signatories earning a return of 14 per cent per annum on their investment in Inmarsat. During 1987, the largest number of investment shares were held by the USA, UK, Norway, and Japan.
Intersputnik
The Russian Federation, that is to say, the former the Soviet Union, is not a member of Intelsat. Instead, in 1971 it created a similar multinational organization named Intersputnik, which provides Fixed Satellite Service (FSS) for its 14 member states and a number of other associated countries. This system uses the various families of former Soviet communications satellites, such as Molniya, Raduga, and Gorizont, using GEO, Highly Elliptical Orbit (HEO), and Polar Earth Orbit (PEO) satellite coverage.
The Russian satellite system can conceivably beam radio broadcasting, TV programmes, voice, and data traffic to almost any location on Earth, and only Intelsat can supply more global FSS links than Intersputnik. It is an open international, intergovernmental organization that any sovereign state can join. The fundamental structure of Intersputnik was determined by the Cooperative Agreement on the establishment of the organization. A representative for each member nation serves on the Board of the Members, which is the main governing body of Intersputnik organization. Besides, this board selects a Director General to chair the Intersputnik Directorate based in Moscow.
The organization also provides three MSS for all three applications, using payloads carried by its GEO spacecraft Gorizont (Horizon), Raduga (Rainbow), and Morya (Seamen).
The Volna (Wave) Network
The Volna MMSC system served to connect maritime and aeronautical MES terminals via space segment constellation to Land Earth Stations (LES) and ground-based telecommunication facilities for former USSR ships and aircraft. This MMSS constitutes communications payloads carried by the GEO spacecraft Gorizont and Raduga. The Volna Network provides radio and TV service for mobile stations on UHF frequency bands between 335–399/240–328 MHz. On the other hand, the Volna Network provides service uplink/downlink on L-band between 1636–1644/1535–1542 MHz for MMSS and also on L-band 1645–1660/1543/158 MHz for Aeronautical Mobile Satellite Service (AMSS) applications, while the feeder link used 6/3 GHz uplink/downlink bands for both MSS applications.
The Morya Network
In 1989, the Soviet Union expanded its MMSS with the Morya MSC Network, using existing Soviet satellites series Morya for carrying the MSC payload. Namely, the Morya Network provided MMSS on two 2.5 MHz wide frequency uplink/downlink bands centered on 1637.25/1535.75 MHz (service link) and 6084.0/3758.3 MHz (feeder link).
The Gals Network
Piggybacked on the former Soviet Union’s Raduga spacecraft, named Gals (Tack), a special telecommunications payload was serving as satellite links for the former USSR’s military forces. Thus, this network will operate using the X-band spectrum for up linking (7.9 to 8.4 GHz) and down linking (7.25 to 7.75 GHz), for defence, maritime, land, and aeronautical applications.
Newly developed mobile satellite communications operators
Handheld and semi-fixed satellite phones have been available since 1998 for professionals in transit and in fixed environments, including those who want satellite telephone access via non-GEO satellite systems at sea, on land, and in the air. These new mobile systems are using Big Little Leo Orbit (LEO) Globalstar and Iridium mobile satellite constellations, concepts that are illustrated in Figure 2. The Big LEO systems provide satellite communication services for maritime, land, aeronautical, personal, and portable users, such as voice (Tel), G3 fax, Public Switched Telephone Network (PSTN), Public Land Mobile network (PLMN), Public Switched Data Network (PSDN), paging, position, velocity and time (PVT) data and SMS services.
Big LEO mobile satellite communication concepts.
Initially, Globalstar, Iridium, Ellipso, Odyssey, Orbcomm, and other mobile satellite operators in development proposed to exploit the Big LEO satellite constellation. Thus, in 1994 Orbcomm and on 31 January 1995 Globalstar, Iridium and Odyssey were awarded licenses by the US Federal Communications Commission (FCC) to operate in the USA. The US Thompson Ramo Wooldridge Inc (TRW) also proposed to exploit the Medium Earth Orbit (MEO) using a configuration of satellites named Odyssey. The Odyssey constellation was to consist of 12 satellites, equally divided into three orbital planes, inclined at 55o to the equator. The satellites were to be placed 10,600 km above the Earth. The FCC awarded TRW a license to establish its MEO satellite system in 1995, with the caveat that building the first two spacecraft should commence by November 1997. Odyssey was predicted to start service in 1999, at an estimated cost of $3.2 billion. Unable to find another major investor willing to support the project, Odyssey was abandoned in December 1997.
The investment of $1.2 billion in Intermediate Circular Orbit (ICO) by Teledesic was announced in November 1999, but after many problems this system was also abandoned. In the meantime, Iridium and Globalstar experienced bankruptcy protection in the USA after a number of difficulties with the establishment of space segments and problems with penetration into the market. Finally, both systems generated sufficient funding to implement the next stage of system development for the upgrade of its terrestrial network and personal satellite communications.
Compared to the Little LEO mobile satellite system Orbcomm, Big LEO systems are expected to be bigger and to have more power and bandwidth for different services to their subscribers. The larger scale of these satellites enables more complex data processing in the transponders than the simple store-and-forward feature of the Little LEO systems.
Globalstar network
Loral Space & Communications, with Qualcomm Incorporation, developed the concept of the Big LEO Globalstar two-way satellite system, at a similar time to Iridium, for all mobile, personal and semi-fixed users. Globalstar gained an operating license from the USA FCC in November 1996. Then, the first launch of four Globalstar satellites occurred in May 1998 by Delta rocket from Cape Canaveral, thereby completing the deployment of 48 satellites plus four spares, using Delta and Soyuz-Ikar rockets. The system uses Code Division Multiple Access (CDMA) and Frequency Division Multiple Access (FDMA) methods with an efficient power control technique, multiple beam active phased array antennae for multiple access, frequency reuse, variable rate voice encoding, multiple path diversity, and soft handoff beams to provide high quality satellite service to users anywhere in the world, even when affected by propagation interference and environmental conditions. Globalstar CDMA is a modified version of the IS-95, which was originally developed by Qualcomm.
Iridium network
The concept of the Iridium two-way mobile satellite system was proposed in late 1989 by Motorola engineers and after the research phase, Iridium LLC system was founded in 1991, with an investment of about $7 billion. Maintaining its lead, Iridium LLC became an operational mobile satellite system on 1 November 1998. After a period of bankruptcy, the Iridium service was relaunched on 28 March 2001. This system was backed by 19 strategic investors from around the world and 17 investor partners also participated in the operation and maintenance of three ground station GES or gateways that link the Iridium satellites for duplex voice and data service to terrestrial wireless and landline public telephone networks. Thus, GES operators around the world also served as regional distributors of Iridium products and added value services in their designated commercial territories. Thanks to intersatellite links, the Iridium system is a satellite-based Big LEO network designed to provide truly global mobile, personal and semi-fixed mobile service of voice, facsimile, paging and data solutions, which also include the with GPS capability for mobile satellite tracking.
Orbcomm network
The Orbcomm mobile and semi-fixed satellite system is a wide area packet switched and two-way data transfer network providing satellite communication, tracking and monitoring services. Orbcomm Global, L.P., from Dulles, Virginia, equally owned by Teleglobe and the Orbital Sciences Corporation, provides global services via the world’s first LEO satellite-based data communications system, which began commercial operations in 1998.
Former international MSS operators
Former international global and regional MSS organizations and operators were Marisat, developed by the US-based Comsat Company Marecs, which was formed by European nations, and Prodat was a project of ESA.
Marisat MMSC network
The world’s first MMSC Marisat system for military applications was unveiled in 1976 with only three GEO satellites and ocean networks that are providing MSC services in the Atlantic, Pacific, and Indian Oceans. The Hughes Aircraft Company, known today as Boeing Satellite Systems Inc, under contract to Comsat General Corp., built three multi-frequency communications spacecraft called Marisat (Maritime Satellite), for the space segment of the world’s first MSC operator. In 1971, frequency bands around 1.6 GHz were allocated for satellite communications with military ships (Navy) and aircraft (Air Forces). The Marisat satellites were designed initially for US Navy vessels and they had a UHF transponder on board in a band from 240 to 400 MHz. Because there was sufficient margin for additional payload, L and C-band transponders were installed on the Marisat satellite to provide commercial MSC traffic for maritime applications.
Although Marisat was also approved for the use of civilian applications, governments of many other countries were not quite content for control of MMSC with their ships to rest with a foreign commercial corporation. Owing to this problem, in 1976, under the aegis of IMO, an agreement was drawn up for the establishment of an Inmarsat organization, initially for maritime service only. Fixed GES for mobile service were located at Santa Paola, US, for POR (GES - 1), at Southbury, US, for AOR (GES - 2) and at Fucino and Yamaguchi, Italy, for IOR (GES - 3), which is shown in Figure 3. The system provided access to the satellites, linking ships at sea through the PSTN with the landline subscribers ashore for Tel, Tlx, fax, data and HSD transmissions. The Marisat system was controlled by Network Control Centre (NCC) located in Washington. Satellite tracking, telemetry and command (TT&C) are also conducted over C-band frequencies.
Marisat Space and Ground Segments.
Marecs MMSC network
The Maritime European Communications Satellite (ECS) of ESA satellite operator or Marecs project covered the study, development, launch, and in-orbit operations of communication spacecraft to be integrated in a global MMSC. Development began in 1973 with funding from Belgium, France, Italy, UK, Spain, and Germany, and subsequently the Netherlands, Norway, and Sweden. In fact, this programme started as the experimental Maritime Orbital Test Satellite (Marots) but was subsequently changed to an operational system resulting in a name change, satellite redesign, and delayed development. The Marecs satellite was part of the MMSC system configured to provide high quality full duplex, reliable real-time voice, fax, Tlx and data services between SES and CES terminals with automatic connection to the terrestrial telecommunication network.
Conclusions
Maritime satellite communication systems are drastically improving traditional radio maritime communications and they can provide backbone to terrestrial and cellular telecommunication networks. Satellite communications play a vital role in the global telecommunications system with approximately 2,000 artificial satellites orbiting Earth and relaying analog and digital signals carrying voice, data and video to and from one or many locations worldwide.
The MMSC system plays a vital role in the global economy, transporting different goods and passengers between continents and countries, with more than 80,000 merchant, cruise and government vessels at sea at any given time. Using MMSC networks globally, the headquarters of shipping companies, ports, and agents can communicate with their fleet, enabling real-time ship monitoring, navigation, and surveillance. In addition, oil rigs can receive and transmit real-time operational data. Crew and passengers can stay connected to family and friends and receive the latest entertainment. Once considered a luxury, broadband connectivity is now viewed as a must-have for maritime vessels.
Another change over time is that modern MMSC onboard terminals have become smaller and more numerous than traditional maritime radio equipment. These terminals have evolved from a few large fixed terminals to thousands of small mobile terminals. Besides, satellites have also become bigger, from early 50kg satellites to modern 10-ton structures with solar panels spanning several tens of meters. Finally, satellites have become much more capable, having evolved over the years from simple state machines to computers with millions of lines of code.