AIS Intelligence

AIS & Maritime Glossary

Plain-English definitions of the terms behind vessel tracking.

AIS (Automatic Identification System)
MMSI
IMO Number
SOG (Speed Over Ground)
COG (Course Over Ground)
Heading
Class A transponder
Class B transponder
Dark ship
AIS gap
Bounding box (bbox)
Draught
Beam
LOA (Length Overall)
Call sign
Ship type
Position report
Voyage
ETA (Estimated Time of Arrival)
Anchored
Underway
Geofence
Congestion score
Nautical mile (nm)
NMEA 0183
VTS (Vessel Traffic Service)
COLREGs
Gross Tonnage (GT)
Deadweight Tonnage (DWT)
TEU
Bunkering
Ballast water
Freeboard
Knot
Port of call
Flag state
Classification society
MID
Rate of turn (ROT)
Navigation status
Satellite AIS
Terrestrial AIS
AtoN
Pilotage
Anchorage