User's Manual

9
About AIS
What is AIS?
The Automatic Identification System (AIS) is a Very High Frequency (VHF) radio
broadcasting system that transfers packets of data over the VHF data link (VDL) and
enables AIS equipped vessels and shore-based stations to exchange identification
information and navigational data. Ships with AIS transceivers continually transmit their
ID, position, course, speed and other data to all nearby ships and shore stations. Such
information can aid greatly in situational awareness and provide a means to assist in
collision avoidance.
AIS equipment is standardized by ITU, IEC, IALA and IMO and is subject to approval by a
certification body. The following AIS devices have been developed for variant
applications.
 AIS Class A:
mandated by the IMO for vessels of 300 gross tonnages and upwards engaged on
international voyages, cargo ships of 500 gross tonnages and upwards, as well as
passenger ships. It transmits typically on 12.5 watt output power.
 AIS Class B:
provides limited functionality and is intended for non-SOLAS commercial vessels
and recreational vessels. It transmits typically on 2 watt output power.
 AIS Receiver:
only receives AIS signal and it does not have transmitter to send out AIS signal.
Suitable for recreational vessel that does not want to send out its vessel
information.
 AIS Base Station:
is provided by aids-to-navigation authorities to enable the ship to shore / shore to
ship transmission of information. Networked AIS Base Stations can assist in
providing overall maritime domain awareness.
 AIS AtoN (Aids to Navigation):
provides an opportunity to transmit position and status of buoys and lights
through the same VDL, which can then show up on AIS-ready devices within the
range.
 AIS SART:
Search and Rescue Transmitter using AIS can be used to assist in determining the
location of a vessel in distress. It is typically used on life rafts.