Automatic Identification Systems

A Class A AIS unit broadcasts the following information every 2 to 10 seconds while underway, and every 3 minutes while at anchor.  It will continue transmitting even if position information is lost. Number, Navigation status, Rate of turn, Speed over ground, Position accuracy, Longitude and Latitude, Course over ground, True Heading, Time stamp. In addition, the Class A AIS unit broadcasts the following information every 6 minutes: MMSI number - same unique identification used above, links the data above to described vessel*IMO number, Radio call sign, Name, Type of ship/cargo, Dimensions of ship, Location on ship, Type of position fixing device, Draught of ship, Destination and Estimated time of Arrival at destination.