What is AIS?

AIS is the mariner’s most significant development in navigation safety since the introduction of radar.  The system was originally developed as a collision avoidance tool to enable commercial vessels to ‘see’ each other more clearly in all conditions and improve the helmsman’s information about his surrounding environment.  AIS does this by continuously transmitting a vessels identity, position, speed and course, along with other relevant information to all other AIS equipped vessels within range.  Combined with a shore station, this system also offers port authorities and maritime safety bodies the ability to manage maritime traffic and reduce the hazards of marine navigation.

Due to the great safety benefits offered by AIS, this technology was made compulsory throughout the world in 2002 for all passenger ferries and vessels over 300 gross tonnes. An AIS transponder determines its own position, speed and course using a built in GPS receiver.  This information is combined with other important navigation information and automatically communicated between AIS equipped vessels without any user interaction.

AIS transponders on other vessels and coast stations receive this information and use it to build up a live graphical display of traffic in the area.  The transponder can be connected to many types of chart plotter or PC charting software using a standard interface protocol.  AIS does not require a radar, but can offer similar capabilities and even enhance a radar image if a radar has already been fitted to the vessel.

The range of coverage of the system is similar to a VHF radio.  The system also has the advantage that VHF radio signals will travel around bends and over islands giving better coverage than radar or enhancing a radar picture when used together.

Benefits of AIS
 

See and be seen
A Class B transponder continuously receives information form all Class A and Class B equipped vessels around you and displays this information on your standard chart plotter or PC. At the same time, your Class B will transmit your position to all AIS equipped vessels automatically.

Safety at night and in poor weather conditions
The Class B AIS is a vital navigation tool in poor visibility conditions. The information received from other AIS ‘targets’ provides the user with vital navigation information and the position transmission alerts other vessels to the user’s location.

• Combined with radar, AIS gives you the best possible picture of your situation in all conditions.
• Position transmission to authorities / nearby vessels in case of emergency.
• Graphically view your position in relation to other vessels when connected to suitable display.
• Track vessels of interest such as friends/ colleagues.

AIS Classes explained

Two types of AIS transponder are available: Class A and Class B. Despite the huge safety benefits of commercial (Class A) AIS, the cost of this advanced technology has previously been a barrier to introducing AIS to leisure craft and light commercial vessels. To overcome this problem the Class B AIS transponder has been developed to provide all the benefits of AIS in a cost effective, reliable and user-friendly product for users that do not need the comprehensive data required for commercial shipping.

The Class B product has been designed with the light commercial and leisure user’s budget in mind, yet still offers all the advantages of AIS. The device can be easily installed and connected to most chart plotters or PC based navigation software.

AIS receivers are also available; these units will pick up broadcasts from both Class A and Class B AIS transponders but do not transmit their own position. A receiver allows you to see the position of other vessels, however your position will not be visible to them.