Maritime satellite communication system is a kind of ship radio communication system using communication satellites as relay stations. It has remarkable advantages such as global coverage (except the Antarctic and Arctic region), all-time, all-weather, stable, reliable, high-quality, large capacity and automatic communication. It can not only improve the ship operation and management efficiency, increase the communication between the ship and the shore, but also help to ensure the safety of human life at sea.
Maritime satellite communication system is a ship radio communication system using communication satellites as relay stations. In 1976, the United States successively launched three maritime communication satellites over the Atlantic, Pacific and Indian oceans, and established the world's first maritime satellite communication station. They mainly served the Navy. In July 1979, INMARSAT was established. Afterwards, in 1982, the first generation of international maritime satellite communication system was established. Although the cost of maritime satellite communication system is expensive, it has plenty of advantages and promising future.
Maritime satellite communication system is composed of communication satellite, shore station and ship station.
I. Maritime communication satellite. It is the relay station of the system to receive and send signals from shore station and ship station. The satellite is deployed in the Pacific Ocean, the Atlantic Ocean and the Indian Ocean. Geostationary orbit satellites are used. The satellite can provide telephone, telegraph, fax and common call services.
II. Shore station. It is a maritime satellite communication earth station located on the coast, which plays as the control role of the communication network. It is equipped with antennas and other equipment. The shore station can be connected with other communication networks on the land.
III. Ship station. It is a maritime satellite communication earth station installed on the ship. It is the communication terminal of the system. It is equipped with parabolic antenna and other equipment. The telephone communication uses frequency modulation and the telegraph communication uses phase shift keying modulation. The communication capacity of each communication satellite is allocated by the network coordination station of the designated shore station. The telegraph channel is pre allocated to each shore station, which is responsible for allocating the time slot for telegraph communication with the ship station. The telephone channel is controlled by the network coordination station and allocated after application of the ship station and shore station.