Connecting an AIS to a tablet

Connect an Automatic Identification System (AIS) to a tablet.

Connecting an Automatic Identification System (AIS) to a tablet like the iPad provides reassuring anti-collision functionality, especially since the portability of the tablet allows for easy monitoring from anywhere on the boat.

What is AIS?

The Automatic Identification System is a VHF communication device between ships that facilitates the exchange of crucial information to prevent collisions. Required on large merchant vessels, its use is becoming more common in recreational boating due to the decreasing costs of equipment.

AIS allows for the reception of information from nearby ships, such as their name and characteristics (size, maneuverability, etc.), as well as their trajectory (heading and speed over the ground).

This data is graphically displayed, with each ship represented by a symbol, a name label, and its trajectory, similarly to what is used in air traffic control.

Example of displaying AIS in "radar" mode.

This data is used to assess collision risks and to set alerts based on two criteria:

  • CPA (Closest Point of Approach) which corresponds to the minimum crossing distance between two vessels.
  • TCPA (Time to Closest Point of Approach) which is the time remaining before reaching the closest crossing point.

An application such as Weather4D Routing & Navigation also calculates the anticipated position of both vessels at the time of CPA.

CPA and TCPA seen on Weather4D

Comparison AIS / Radar

Although aiming for a similar objective, namely the detection of surrounding obstacles, AIS should not be confused with radar. Each device has its own advantages and disadvantages, and the optimal solution would be to use them together!

For small vessels seeking an economical detection solution, AIS is an excellent alternative to radar and proves to be very useful for navigation in dense traffic areas or near cargo lanes, for example.

Receiver or transponder?

An AIS receiver provides safety by allowing you to view surrounding traffic, but it does not allow other ships to detect you. For that, it is necessary to opt for a transponder that broadcasts your position.

The use of a transponder thus increases your safety (you are more likely to be spotted) and contributes to the overall AIS ecosystem, which would be useless if there were only receivers without transmitters.

Historically, the prices of transponders were high, but wifi-equipped models that are more affordable are starting to emerge on the market. An alternative is to connect a wired AIS transponder to a Wifi multiplexer.

Connect an AIS to the tablet

On the market, there are a multitude of AIS receivers and transponders that typically broadcast data in NMEA 0183 or 2000 formats. To capture them on an iPad or an Android device, it is necessary to convert them into a WiFi signal.

If your boat already has an AIS system, whether it's standalone or integrated into your VHF, you can use a NMEA to WiFi converter such as the Miniplex-3wi-n2k.

If you do not have AIS, you might consider a device with built-in WiFi, such as the iAISTX from Digital Yacht or the XB-8000 from Vesper Marine, the latter also offering NMEA0183/2000 connectivity for other equipment. More recently, the Nomad was launched, providing an easy-to-install WiFi transponder thanks to a USB port.

AIS Wifi Transponder Nomad2 from Digital Yacht

Visualize the AIS

After receiving the AIS signal on the tablet, it needs to be visualized. You can choose between a "radar" display or a marine chart display.

The free "radar" application iAIS is notable because it allows for the overlay of AIS information on a Navionics chart (which does not qualify it as a true navigation application).

For complete integration with a navigation application, including collision alarm management, several high-performing applications are available, such as Weather4D Routing and Navigation, Sailgrib WR, iNavX, and iSailor.

AIS targets visualized in iNavX.

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