Real and Virtual AIS beacons

[Roberto]

French MRCC (CROSS) are testing two types of AIS beacons.

One type, is simply an AIS transmitter put on a buoy, which is then floated in the appropriate spot (for ex. where a ship has just sunk)

The second type I personally find stunning: the CROSS shore station transmits an AIS signal with the coordinates of a point over the sea (ex. where a ship has just sunk, or there are floating containers, or whatever), the ship receiving stations decode this signal which displays on their screens as an AIS beacon in the middle of the sea (where naturally there is physically no transmitting station, which is on shore).

Also, there are talks lighthouses are going to be fitted with AIS transmitters, maybe the last step before eventually turning their lights off forever ?

Is there any similar testing in the UK, or (to those having AIS fitted) have you ever seen any beacon like these in the Channel ?


This whole AIS thing seems to have a very bright future

 

[Amphitrite]

AIS is capable of transmitting virtual AIS Aids-to-Navigation (AtoN). In general, AIS can transmit AtoN data in three different ways:
1. real AtoN: a special transmitter is fitted on the AtoN (might be a problem to find a suitable power supply)
2. synthetic AtoN: from a remote station AIS AtoN data is overlayed over a physically existing AtoN
3. virtual AtoN: AIS AtoN data is transmitted and will be visible on users screens, but there is no physical AtoN (used for emergency marking of wrecks etc. where it has not yet been possible to deploy a buoy).

The possibilities 1 and 2 I have already seen, and no 3 will probably tested by quite a couple of lighthouse authorities in Europe this year.
AIS on lighthouses is currently seen as a replacement or compliment to RACON.

 

[Roberto]

on this site (http://www.marine-marchande.net)
there are recent images (jan08) of a virtual AtoN placed around the position where M/V Ice Prince sank on Jan13, north of cherbourg

this is the detailed view

I haven't got AIS on my boat, but AtoN signals look the same as the two other ships on the screen, is there a way to distinguish between signals of different type ?

thanks

 

[Amphitrite]

AIS AtoN signals use different messages than vessels and have an indicator towards their nature. They should be displayed as small square standing on one tip with a cross (marking the exact position) inside.