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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
Vessel information
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AIS Classes
There are seven types of AIS stations; vessels, base stations,
Aids to Navigation (AtoN), Search and Rescue (SAR), Search
and Rescue Transmitter (AIS-SART), MOB (Man OverBoard)
and EPIRB (Emergency Position Indicating Radio Beacon)-
AIS.
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.
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OVERVIEW
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Summary of Contents for MA-500TR
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