AIS - Automatic Identification System equipment

What is AIS?

The Automatic Identification System (AIS) is included in the International Convention for Safety of Life at Sea (SOLAS) and large ships began fitting AIS in July 2002.  AIS transmits, automatically and at set intervals, dynamic information relating to the ships course, speed and heading,; static information related to the ships name, length, breadth and voyage related details such as cargo information and status (underway, at anchor).

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 send and receive identification information that can be displayed on a computer or chart plotter.

This information can assist in situational awareness and provide a means to assist in collision avoidance.  In addition, AIS can be used as an aid to navigation,

by providing location and additional information on buoys and lights.

The Types and Classes of AIS

There are two classes of AIS, Class A and Class B, as well as different types of AIS used for shore stations (AIS Base Stations), aids to navigation (AIS AtoN), AIS on search and rescue (SAR) aircraft and AIS search and rescue transmitters (AIS SART).

Equipment Description

Each AIS Class B station consists of one VHF transmittertwo VHF receivers (AIS 1 and AIS 2), a standard marineelectronic communications link and sensor input from different onboard systems. Timing and positional information comes from a GNSS (global navigation satellite system - such as GPS).  Heading information may come from an additional sensor, such as a compass.