There is a lot of confusion in leisure sailing about what AIS is exactly.

In few words, AIS is a technology that can send and receive static data (identifying the boat) and dynamic data (coming from a GPS) over two VHF channels in a coverage radio that can reach up to 60NM in optimal conditions, although the usual coverage reaches 30NM. An AIS transponder needs then to be connected to a VHF antenna and a GPS one too. The GPS antenna can be the one already on board, although the VHF one must be a dedicated one, since AIS emissions and VHF voice working with the same antenna is uncompatible. We have a splitter solutions for AIS reception though.

Such data, when received, can be displayed on any device compatible with NMEA data, like plotters, pc’s and pda’s, over electroncic vector or raster charts, turning such devices in real radars, although better than them, since:

  • Targets are identified, and unlike on radars there is no confusion between geographical targets and ships. This means that a mariner can call directly another boat by its name.
  • It is not affected by meteo conditions
  • Targets show up in electronic charts, so lots of valuable information are added to the display.
  • Its coverage is far larger, since it can reach 60NM.
  • It’s price and size are far lower (you can visit our productos here ) as well as its energy consumption (an average 6W).


Such confusion is caused by the fact that:

- there are several AIS standards, A for SOLAS ships with a very high price, and B specially designed for small boats such as leisure craft or fishing ships, with a far lower price.

- it is sometimes wrongly called radar. Although it is true that one of its many applications converts AIS into an improved radar, both technologies have very little in common.

- not every AIS devices are able to transmit and receive, and not even all of them are able to receive in the two channels especially dedicated to AIS. Besides, many of them do not carry an incorporated GPS, so they make installation far more difficult.

True Heading produces double channel receivers and transponders, able to transmit and receive, besides a wide range of AIS products designed for proffesional customers.

Furthermore, not many people know that the new standards will be able to transmit information from the coast such as aids to navigation that will graphically inform mariners on real-time on their computer screens about possible accidents or dangerous areas, buoyes, lighthouses, etc…

As a conclusion, AIS is the first step towards what we call e-navigation, adding a new dimension to security at sea, and making it possible to create a new range of services totally unthinkable until today in the leisure nautical environment.