Automatic Identification System ("AIS")
Automatic Identification System ("AIS") is a International Maritime Organization standard for digital tranmission of vessel information. Regulation 19 of SOLAS Chapter V mandates large commercial vessels be fitted with AIS equipment and operate it at all times.
The regulation requires that AIS-equipped ships shall:
The technology works on a couple of VHF frequencies using Self-Organizing Time Division Multiple Access to permit vessels to report and update their position information in real time. The U.S. Coast Guard has an excellent overview of AIS and how it works.
This is useful stuff for the cruising sailor. One of the great fears of any bluewater sailor is of crossing paths with a huge commercial vessel that, like some cruisers, may not be keeping a good watch. With an AIS receiver hooked up to the chartplotter or navigation computer, the on-watch crew is less likely to be surprised by another vessel because the system can generate an audible warning as soon as an AIS-broadcasting vessel comes within a defined range.
While AIS transmitters are expensive, costing in the thousands of dollars, an AIS receiver, possibly as cheap as one hundred dollars, is within the reach of cruisers. There are more and more manufacturers making AIS transpoders and receivers, such as Smart Radio Holdings, Milltech Marine, Euronav, Nobeltec, and Sealinks, maker of a $1,500 Class B AIS transponder.
NASA Marine Instruments promises a standalone AIS receiver/plotter that displays AIS information in a radar-like format. They also have a AIS receiver that will send AIS NMEA sentences to a serial port on your computer or to other navigation electronics using the NMEA 2000 bus interface.
It seems a no-brainer for this technology to be incorporated into VHF radios but we have yet to see one offered or announced, despite Chuck Husick's May 2005 BoatU.S. Techno-Talk article entreating all recreational boaters to request manufacturers do so.
The regulation requires that AIS-equipped ships shall:
* provide information - including the ship's identity, type, position, course, speed, navigational status and other safety-related information - automatically to appropriately equipped shore stations, other ships and aircraft;
* receive automatically such information from similarly fitted ships; monitor and track ships;
* exchange data with shore-based facilities.
The technology works on a couple of VHF frequencies using Self-Organizing Time Division Multiple Access to permit vessels to report and update their position information in real time. The U.S. Coast Guard has an excellent overview of AIS and how it works.
This is useful stuff for the cruising sailor. One of the great fears of any bluewater sailor is of crossing paths with a huge commercial vessel that, like some cruisers, may not be keeping a good watch. With an AIS receiver hooked up to the chartplotter or navigation computer, the on-watch crew is less likely to be surprised by another vessel because the system can generate an audible warning as soon as an AIS-broadcasting vessel comes within a defined range.
While AIS transmitters are expensive, costing in the thousands of dollars, an AIS receiver, possibly as cheap as one hundred dollars, is within the reach of cruisers. There are more and more manufacturers making AIS transpoders and receivers, such as Smart Radio Holdings, Milltech Marine, Euronav, Nobeltec, and Sealinks, maker of a $1,500 Class B AIS transponder.
NASA Marine Instruments promises a standalone AIS receiver/plotter that displays AIS information in a radar-like format. They also have a AIS receiver that will send AIS NMEA sentences to a serial port on your computer or to other navigation electronics using the NMEA 2000 bus interface.
It seems a no-brainer for this technology to be incorporated into VHF radios but we have yet to see one offered or announced, despite Chuck Husick's May 2005 BoatU.S. Techno-Talk article entreating all recreational boaters to request manufacturers do so.
