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AIS - Automatic Identification System                                             Skysail Home

AIS - see pdf presentation ais.pdf

For an example AIS display see here  www.boat-angling.co.uk.    Using an AIS receiver and a display, you see a radar-like real-time chart of all the large ships manoeuvring in your area. 

AIS is a system for ships to communicate their positions as part of the global maritime safety system (GMDSS).  Ships over 300 tons carry an AIS system which broadcasts information about the ship  AIS uses bursts of high speed data on two VHF channels in the marine band. 161.975 (Ch 87) and 162.025 (Ch 88) MHz. 

Ships broadcast their identity, type, MMSI number, position, course, speed and destination so that other ships can take account of their movements.  This is automatic data and reliable.

Other data is status (RAM, Underway, NUC, etc) draught, length, cargo, number of passengers.  Do not rely on this kind of data for collision avoidance.

AIS is required for VTS systems in ports.   Security was a major motivator for installation of AIS in USA post 9/11.

All about  AIS  http://www.allaboutais.com/index.php/en/

Cautions on AIS accuracy:  http://www.nautinst.org/ais/PDF/AIS_Human_Factors.pdf

 

posted 6th November 2012