Maritime glossary · Automatic Identification System
AIS
The VHF radio system every commercial vessel uses to broadcast its position, course, and identity.
Definition
AIS (Automatic Identification System) is the maritime equivalent of an aircraft transponder. Every SOLAS-class vessel above 300 GT on international voyages, every passenger ship, and every commercial vessel above 500 GT on domestic voyages must broadcast an AIS signal at all times. The signal carries the vessel’s MMSI, IMO number, position, course over ground, speed, navigational status, destination, and ETA. Coastal receivers and satellite constellations pick up the broadcasts and feed them into AIS data providers, which is how live ship tracking maps work.
Worked example
A 50,000 DWT bulker entering the English Channel broadcasts its AIS every few seconds. Vessel Hunter ingests the feed and matches the IMO number against the ownership tree, so the next thing you see is not just a dot on a map. It is the operator contact.
How Vessel Hunter uses AIS
Vessel Hunter fuses terrestrial and satellite AIS into one continuous feed, normalises the raw NMEA into a clean vessel record, and pairs each broadcast with the verified decision-maker behind the ship.
How Vessel Hunter handles AIS →
Related terms
- MMSIMaritime Mobile Service Identity
The nine-digit identifier broadcast by a vessel’s AIS and used to route VHF radio calls.
- IMO NumberInternational Maritime Organization Number
The seven-digit identifier permanently assigned to a ship, never reused, never changed, even on resale or reflag.
- SOLASSafety of Life at Sea
The principal IMO convention on the safety of merchant ships, covering construction, fire protection, life-saving, navigation, and more.
The bigger picture
AIS is one piece of the commercial maritime picture Vessel Hunter pulls together for shipyards, suppliers, service providers, and port agents. Every vessel record bundles AIS, ownership, inspections, dry-dock history, casualty record, classification status, and a verified contact for the operator decision-maker behind the ship, so the team that reaches out first wins the work.
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