AIS is a cooperative VHF system for exchanging ship data.
Equipped ships and shore facilities automatically exchange identity, position, course, speed, navigational status and other safety-related information. The system helps identify and track ships, supports search and rescue and information exchange, and improves situational awareness as a supplement to radar and other navigation information. Shipborne AIS information is divided into static data, automatically sensor-updated dynamic data apart from manually entered navigational status, and manually maintained voyage-related data.
Not all ships carry AIS, fitted units may be switched off in limited safety or security circumstances, and received data may be incomplete, unavailable or wrong.
