Automatic Identification System
Automatic Identification System (AIS) is a way for a ship to send data by radio to tell other ships its position. AIS was made to avoid ships colliding and make it safer to travel by sea. AIS sends messages every few seconds, and these are received other boats and by stations on land and on some satellites. A ship knows its position by using Global Positioning System (GPS). Since 2004, all ships above 300 tons and all passenger ships have to use AIS. It is now also used by many yachts and other leisure boats.
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Technology