Installation and Operation Manual

About your AIS class B transceiver
Page 8
2 About your AIS class B transceiver
2.1 About AIS
The marine Automatic Identification System (AIS) is a location and vessel
information reporting system. It allows vessels equipped with AIS to
automatically and dynamically share and regularly update their position,
speed, course and other information such as vessel identity with similarly
equipped vessels. Position is derived from the Global Navigation Satellite
System (GNSS) and communication between vessels is by Very High
Frequency (VHF) digital transmissions.
There are a number of types of AIS device as follows:
● Class A transceivers. These are similar to class B transceivers, but
are designed to be fitted to large vessels such as cargo ships and
large passenger vessels. Class A transceivers transmit at a higher
VHF signal power than class B transceivers and therefore can be
received by more distant vessels. They also transmit Class A
transceivers are mandatory on all vessels over 300 gross tonnes on
international voyages and certain types of passenger vessels under
SOLAS regulations.
● Class B transceivers. Similar to class A transceivers in many ways,
but are normally lower cost due to the less stringent performance
requirements. Class B transceivers transmit at a lower power and at
a lower reporting rate than class A transceivers.
● AIS base stations. AIS base stations are used by Vessel Traffic
Systems to monitor and control the transmissions of AIS
transceivers.
● Aids to Navigation (AtoN) transceivers. AtoN’s are transceivers
mounted on buoys or other hazards to shipping which transmit
details of their location to the surrounding vessels.
● AIS receivers. AIS receivers will generally receive transmissions
from class A transceivers, class B transceivers, AtoN’s and AIS base
stations but do not transmit any information about the vessel on
which they are installed.