Introduction to Automated Identification Systems (AIS)

Principally intended for collision avoidance, but as an adjunct rather than an automated collision avoidance system. 

Complements collision avoidance of ARPA and VTS.

International Convention for the Safety of Life at Sea (SOLAS)

requires AIS to be fitted aboard international voyaging ships of 300 or more gross tonnage, and all passenger ships regardless of size.

Other applications

can serve to transmit navigation aid and marker positions. These aids can be located on shore, such as in a lighthouse, or on the water, on platforms or buoys.
The US Coast Guard suggests that AIS might replace RACON, or radar beacons, currently used for electronic navigation aids.


Self-organizing network principally using VHF radio interaction between AIS on vessels or between vessel AIS & virtual AIS beacon

AIS transponders (transmit function)

The signals are received by AIS transponders  (receive function)


AIS Installation Classes

Options for safety level and cost

Class A - mandated for use on SOLAS Chapter V vessels (and others in some countries).

Class B - a low power, lower cost derivative for leisure and non-SOLAS markets.GG

Other variants are under development specifically for base stations, aids to navigation and search and rescue, though they will all be derived from one of the existing standards and inter-operate with them.

AIS Synthetic Beacons

AIS Shore-based stations

Aids to navigation. 
Normally reports every three minutes. 
This may eventually replace radar beacons (RACON).

AIS can create a “synthetic beacon”

Radar beacons had to be physically on the hazard
AIS can simply add the position of a hazard to the broadcast
Wrecks, spills, etc. could be flagged in minutes