AIS matters because it makes selected vessel information available to ships and shore users, supporting situational awareness and coordination. This cooperative VHF data system allows equipped ships and shore facilities to automatically exchange identity, position, course, speed, navigational status and other safety-related information. By sharing these details, AIS helps identify and track ships, supports search and rescue efforts and facilitates information exchange. It serves as a supplement to radar and other navigation information rather than replacing them.
A typical ship-to-ship AIS range at sea is stated by the International Maritime Organization as 20 to 30 nautical miles depending on antenna height. However, terrain, stations and radio conditions prevent a guaranteed universal range for all users. 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.
