The Automatic Identification System (AIS) is a maritime navigation safety communications system standardized by the International Telecommunication Union (ITU), adopted by the International Maritime Organization (IMO), that provides vessel information, including the vessel’s identity, type, position, course, speed, navigational status and other safety related information. AIS is designed as a ship collision avoidance system for terrestrial use and uses a communication scheme called Self-Organized Time Domain Multiple Access (SOTDMA). AIS also offer important ship monitoring services to coastal guards or search and rescue organizations.
Ship-to-shore and ship-to-ship communication is limited by the horizon, and the signal reception is highly dependent on the altitude of the transmitter antenna located onboard the ship. Satellite-based AIS is presented as a promising solution to overcome the terrestrial VHF coverage limitation with the potential to provide AIS detection service coverage on any given area on the Earth.