AIS

The Automatic Indentification System (AIS) is an automatic tracking system used on ships and by vessel traffic services (VTS) for identifying and locating vessels by electronically exchanging data with other nearby ships, AIS base stations, and sometimes satellites. AIS information supplements marine radar, which continues to be the primary method of collision avoidance for water transport.

The International Maritime Organization's International Convention for the Safety of Life at Sea requires AIS to be fitted onboard international voyaging ships with gross tonnage (GT) of 300 or more, and all passenger ships regardless of size.