AIS is a cooperative maritime VHF information-sharing system for identifying and tracking ships. It enables equipped vessels and shore facilities to automatically exchange identity, position, course, speed, navigational status and other safety-related data.
This exchange supports search and rescue operations, facilitates information exchange, and improves situational awareness as a supplement to radar and other navigation information. The system helps mariners maintain a clear picture of their surroundings by providing continuous updates on nearby traffic.
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. Static details include the vessel's name and call sign, while dynamic updates reflect its real-time movement and operational state.
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. Users must understand that AIS is a supplementary tool rather than a standalone collision-avoidance system, requiring constant verification against other available means of navigation.
