Automatic Identification System
The Automatic Identification System (AIS) is a shipboard broadcast VHF transponder system, sending data about the identity of a ship. Its name, MMSI number, its latitude and longitude, speed, course and heading. All vessels over 300 gross tonnage and all passenger vessels are obliged to carry an AIS transponder.
This transponder assists in traffic monitoring, management and collision prevention. The data is sent continuously and is useful to yachtsman, particularly in busy shipping areas.