What is AIS

View of AIS targets on Transas Navigator screen

AIS is short for Automatic Identification System. Starting 01.01.2005 all SOLAS-Ships above 300 tons and all passenger vessels are to be equipped with AIS. All ships equipped with AIS permanently broadcast information about their MMSI-number, call sign, name, position, course, heading, speed, rate of turn and type of vessel via two dedicated VHF channels (CH 87 B and 88B).

You don’t have to guess whether the vessel that just appeared over the horizon might be dangerous for you, as your AIS automatically calculates the CPA (Closest Point of Approach) and TCPA (Time to Closest Point of Approach). And if you know its’ name and call-sign, you can give the vessel a call on VHF or make a DSC-call. Moreover, AIS provides target disclosure where radar is unable to display it - behind the isle, river bend, etc.

However the AIS-system is not a replacement for the radar but rather an amendment. AIS can only display targets transmitting AIS-data, but not other objects dangerous to safe navigation, namely land, floating objects, fishermen, navy ships, etc.

Participating in the AIS-system is of great advantage for pleasure boats. Now AIS enables you to display AIS-data on your normal laptop in compliance with IMO and IALA recommendations. All you need is the AIS software and a small AIS receiver.