About Your Ais Receiver; About Ais - Humminbird RX AIS Installation And Operation Manual

About your AIS receiver

2 About your AIS receiver

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 Positioning System (GPS) and communication
between vessels is by Very High Frequency (VHF) digital transmissions.
There are a number of types of AIS devices 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 more frequently. 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, AtoNs and AIS base stations but do not transmit any information about the vessel on
which they are installed.
This product is an AIS receiver.
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