ICOM 322800 Manuale Utente

1

D ABOUT AIS

AIS is an acronym for “Automatic Identification System.”
An  AIS  transponder  is  a  short  range  data  radio  unit,  used 
primarily for collision-risk management and navigation safety. 
It  automatically  transmits  and  receives  vessel  information 
such as the vessel name, MMSI code, vessel type, position 
data, speed, course, destination and more. Information is ex-

changed among the vessels and/or base stations on the VHF

maritime mobile band. The information helps to identify other 
nearby vessels or stations by displaying the received data on 
a plotter or a radar screen.

Your vessel

(Class B AIS)

Other vessel

(Class A AIS)

Other vessel

(Class B AIS)

Base Station

D

There are four types of AIS stations; vessels, base stations, 
Aids to Navigation (AtoN) and Search and Rescue (SAR).

There  are  two  classes  of  AIS  units,  which  are  installed  on 
vessels; Class A and Class B.

Under  the  Safety  Of  Life  At  Sea  (SOLAS)  convention,  all 
SOLAS vessels, as described below, are required to install a 
Class A AIS transponder

:

• Upwards  of  300  gross  tonnage  engaged  on  international

voyages.

• Passenger vessels, irrespective of size, engaged on inter

-

national voyages.

• Upwards of 500 gross tonnage not engaged on international

voyages.

A Class B AIS transponder is designed to be interoperability 
with Class A units, but not to impact the Class A network.
Many commercial vessels, and some leisure craft, not clas-
sified as requiring a Class A unit, choose to install a Class B 
unit to avoid accidents at sea.

1

1

New2001