The evolution of AIS on board

Interview with Andrew Armstrong from Comar Systems, who designs and manufactures bespoke AIS equipment for MarineTraffic.


MarineTraffic station owners will already be familiar with Comar Systems as they produce the kit required to set up an AIS receiving station. Formed 30 years ago, Comar Systems are world leaders in the field of Automatic Identification Systems (AIS) and from their base on the Isle of Wight in the UK they manufacture AIS receivers, splitters and antennae for both commercial vessels and pleasure craft. Comar Systems originally specialised in GPS equipment, and this knowledge is now combined with AIS to provide vessel position information.

The standard receiver used by MarineTraffic station owners is an SLR350Ni – the i at the end of the product name stands for “integrated” because, unlike other receivers, this one has a built in single board computer. This means that it is very convenient for AIS stations in remote locations as there is no need to connect it to any other equipment. AIS data is collected by a two channel VHF receiver and then processed by a Raspberry Pi mini-computer which then forwards the data on to MarineTraffic and subsequently appears on the screen as real time vessel positioning.

Andrew Armstrong says: “The AIS system itself hasn’t really changed over the past decade and isn’t likely to in years to come. However, the alternative ways to use AIS now go above and beyond the original scope of collision avoidance. Comar Systems has seen increasing demand for AIS used in government and port security systems, to keep track of vessels in a specific area. AIS receivers are also being placed into drones that are able to look at what is going on around a particular ship or port. There has also been some test work in using AIS to send data from offshore windfarms which are actually visible on”

AIS is being used in increasingly innovative ways which go beyond just vessel monitoring. According to Andrew Armstrong AIS is being used to measure wave heights by sending data from buoys which have Comar’s SLR350Ni attached. An increasing number of buoys are able to send a range of measurements including average wind speed, wind gust speed, average wind direction, gust direction, wave height, wave period and water temperature via AIS.  AIS is also being used for surveillance tasks with equipment set up to monitor a specific area, such as a pipeline or offshore installation, using vessels in the area.

MarineTraffic Network AIS

Over the years, the adoption of the equipment manufactured by Comar Systems has changed significantly. To begin with their kit was mainly used by leisure vessels. Now, however, this has increased to include commercial vessels which are required to do so by the International Maritime Organisation (IMO) – all vessels of 300 gross tonnes or carrying more than 11 passengers must install a Class A  AIS. Two types of AIS transponder are now available, Class A and Class B.

Class B transponders have been developed to provide the safety and navigation benefits of AIS to smaller vessels with lower cost and simpler installation when compared to Class A.

But today an increasing number of recreational sailors are installing AIS to allow them to enhance their experience on the water by using it as a navigational aid as well as sharing their position with friends and potentially reducing their insurance costs. Andrew Armstrong notes that most yacht race organisers have made AIS a mandatory requirement for the majority of races.

Earlier this year, MarineTraffic worked together with Comar Systems on a trial programme to monitor over 1000 sailing boats participating in the annual Round the Island Race, which is a one day yacht race around the Isle of Wight in the UK. In previous years, the race has been monitored through a mobile phone app, but with poor phone coverage on the island this system proved unreliable. So together with Comar, MarineTraffic placed some extra AIS receivers temporarily around the island to provide full coverage of the race. These receivers then relayed the AIS data on to to provide real time vessel data that was used by the Royal National Lifeboat Institution (RNLI) who were on hand to help any yachts and crews in distress.

Working together with Comar Systems, MarineTraffic is increasing transparency within the maritime world and beyond. Not so long ago, it was inconceivable to be able to monitor the whereabouts of a vessel once it had left a port and today in contrast, the possibilities seem limitless.


Become a member of the MarineTraffic Network crew. Apply for a free AIS receiver here