AIS transponders automatically broadcast information, such as their position, speed, and navigational status, at regular intervals via a VHF transmitter built into the transponder.
The information originates from the ship’s navigational sensors, typically its global navigation satellite system (GNSS) receiver and gyrocompass. Other information, such as the vessel name and VHF call sign, is programmed when installing the equipment and is also transmitted regularly.
The signals are received by AIS transponders fitted on other ships or on land based systems, such as VTS systems. The received information can be displayed on a screen or chart plotter, showing the other vessels’ positions in much the same manner as a radar display.
Operating in the VHF marine band, the AIS ( Automatic Identification System ) system enables the wireless exchange of navigation status between vessels and shore side traffic monitoring centres. Commercial ships, ocean-going vessels and recreational boats with AIS transceivers broadcast
The Benefits of AIS.
Transmit your position fitting a Class B  AIS device ensures you are seen by other AIS equipped vessels.
Vessel Protection.
As part of a suitably configured network, AIS enables owners to be alerted to unauthorised vessel movements.
Port Management.
AIS can be used as a highly effective port management tool allowing easy identification, control and direction of vessels.
Coastal Surveillance.
AIS and radar can be fused to create effective and efficient coastal tracking, surveillance and safety systems.
Types of AIS Systems.
There two types of AIS systems, Raymarine has the AIS350 duel channel receiver which enables you to receive important vessel navigation information in your area.
Raymarine also has the AIS 650  which transmits your vessel data and navigation information to other vessels in your area. The AIS data is displayed on your chart plotter overlaying the chart detail.
This article was supplied by Eugene Bonello Stargate Marine, 158 – 170 Nelson Place, Williamstown VIC, the authorised local Raymarine Dealer.