Maritime Glossary
Automatic Identification System
Also known as: AIS
A VHF transponder system that broadcasts a vessel's identity, position, speed, and course to nearby ships and shore stations.
Status: ActiveVerified: Source confidence: high (97%)
Full Definition
The Automatic Identification System (AIS) is a VHF-based tracking system mandatory under SOLAS for vessels of 300 GT and above on international voyages, all cargo ships ≥500 GT, and all passenger ships. Vessels broadcast static data (name, IMO number, call sign, type, dimensions), dynamic data (position, COG, SOG, heading, rate of turn), and voyage data (draught, destination, ETA) at regular intervals. Class A (ship-borne) transponders update every 2–10 seconds underway. AIS is fundamental to collision avoidance, VTS, SAR, and maritime traffic monitoring.
Domain Tags
navigationsafetyregulation