01 September 2022
Automatic Identification System, or AIS for short, is a marine technology that allows vessels of all sizes to exchange navigational information and identity with each other and with shore-side traffic monitoring systems. The system was conceived to enhance safety on the high-seas, and reduce the number of collisions between ships and small craft by enabling them to better see each other, identify each other, and communicate their maneuvering intentions.
The AIS system works in the VHF maritime radio band, technically on what used to be channel 70. A full-function AIS transceiver is connected to the vessel’s navigation system and automatically transmits updated information to other users in radio range. Commercial ships, ocean-going vessels and recreational boats equipped with AIS transceivers broadcast AIS messages that include the vessel's name, course, speed, and current navigation status.
Today there are 3 different kinds of AIS products in the marketplace known as Class A, Class B and Receive Only systems. There are some key differences between them so it is very important to understand how they work when shopping for an AIS solution for your boat.
Class A AIS Transceivers are at the top of the pyramid. These units were the first on the scene, offer the most capability, and are also the most expensive. Class A transceivers are required to be carried by nearly every oceangoing commercial ship and are designed to comply with international standards set by the International Maritime Organization (IMO) and the Safety of Life At Sea (SOLAS) treaty.
Class A transceivers update more frequently than other options, and broadcast more information about the vessel they are installed on. These units are more complex to install than other options, so typically are found only on commercial ships, towing vessels, workboats, government vessels and large ocean-going yachts. Class A units have their own, dedicated, GPS/GNSS antenna that is independent of the boat’s other systems. They can also integrate with the vessel’s gyrocompass and other electronics.
Class A units will have their own dedicated display and controls, as well as outputs to the vessels electronic chart and radar display systems. Raymarine’s AIS4000 is a Class A Transceiver unit that complies with IMO and SOLAS standards for commercial vessels.
Raymarine also offers the AIS5000 Class A Transceiver for First Responders. This unit is widely used by the United States Coast Guard, other government agencies, as well as federal, state and local marine law-enforcement agencies. AIS5000 supports encrypted data exchange, blue force tracking and other advanced capabilities.
Class B AIS Transceivers are intended for recreational vessels, smaller workboats, and vessels not required to carry a Class A transceiver. Class B AIS transceivers offer many of the same capabilities as the more advanced systems, in a size and price-point that is more reasonable for recreational boating. Many Class B transceivers are “headless” black-box units the deliver their data directly to your networked chartplotter, radar and instruments. AIS contacts can be displayed as an optional layer on your radar scope, navigation chart, or in an augmented reality video display. Class B units transmit with less power than Class A units, giving them shorter range. They also provide updates to surrounding vessels at a longer interval than a Class A unit will.
Raymarine’s AIS700 is an example of a black-box AIS transceiver with a built-in antenna splitter. This allows you to share a common VHF antenna between the AIS and VHF radio, or you can dedicate an antenna to each device. AIS700 also comes with its own, dedicated GPS/GNSS antenna system that ensure it always knows where the boat is located, independent of other onboard systems.
Receive-Only AIS is an inexpensive solution that allows your onboard electronics to receive the AIS broadcasts from Class A and Class B systems nearby and display them on your chart, radar and instruments. Receive-only AIS systems do not send any information about your vessel out to other nearby AIS users. Raymarine’s AIS350 is an example of a receive-only GPS device.
Some marine VHF radios also offer built-in AIS receivers. Our Ray73 and Ray91 VHF radio models can receive AIS information and relay it to your boat’s chartplotter, radar and instruments. These radios do not transmit AIS data about you to other vessels.
The AIS system is all about enhancing safety on the water and reducing the chances of colliding with another vessel by allowing captains to clearly see the movements of each other vessels. When connected to a Raymarine chartplotter or MFD, AIS targets can be displayed as a layer on top of the live radar or chart display. AIS contacts can be colorized red or green to help differentiate between vessels that might present a hazard versus other traffic. AIS data can be used to calculate a vessel’s Closest Point of Approach (CPA) and sound alerts to the Captain when action is necessary.
AIS also provides positive identification of other vessels nearby. A quick tap or touch on an AIS target icon will reveal that vessel’s name, radio call sign, MMSI number and other details that make it much easier to raise them on VHF voice or DSC messaging.
Fitting a Class A or Class B transceiver to your boat also helps to make your boat more visible to other AIS equipped vessels. By broadcasting your position and identification to them, your boat should appear on their radar and chart display, making you more visible to watch standers.
In the event of an onboard emergency, having a Class A or Class B AIS Transceiver onboard also makes it significantly easier for emergency responders to locate your boat. All modern search, rescue and response vessels and aircraft are equipped with AIS technology for locating vessels in distress.
Check out the latest Raymarine AIS products here.