Automatic Identification System (AIS)

AIS. This provides a terrestrial based monitoring system of suitably equipped ships. This information is collected by both shore stations, other vessels and nowadays satellites, thus enabling other equipped vessels to be aware of and identify other vessels in their area. Much additional data, not normally obtainable by other means, regarding ship characteristics, as well as potential destination and likely manueovres can be encoded in the transmitted messages. There are two main classes of ships which transmit (Class A and Class B) plus SAR aircraft and shore stations can broadcast AIS data. The different types of data message are discussed as well the different AIS equipment and different display options of AIS data. New radar equipment on IMO ships since 2008 must include AIS and ARPA into one Target Tracking (TT) display. The collect of AIS data into terrestrial shore based and satellite based networks is covered as well as the LRIT system, which has some similarities in function to AIS. The chapter also includes a comparison of AIS and radar in terms of detection, anti-collision and performance.