AIS Virtual Buoys

[richardbrennan]

I am sure many of you will have seen the article in the news section of Yachting Monthly concerning AIS virtual buoys. I have a Digital Yacht AIT2000 transponder which is linked by NMEA 2000 to a Garmin 5012 plotter. According to the article, the Digital Yacht AIS should receive these virtual markers, so I phoned Garmin to see if my plotter would display them. I got an answer that has confused me in that what I was told was that the plotter would display them, but just as another target, and the individual I spoke to clearly thought that there would be something physical at the location generating the signal, which is rather at odds with the whole concept. The other question that springs to mind is what is the likely range of such beacons, which I realise will to some extent will be dependent on my aerial height, but how and where are such signals generated?

All help gratefully received!

 

[prv]

You're speaking somewhat in the future tense - I'm sure I was making chart corrections swapping buoys for AIS over a year ago

If your Garmin doesn't implement the AIS spec properly (as is sadly all too common among plotter manufacturers) then it will most likely show the AtoN as a stationary ship. My Vesper display shows them as diamond symbols, and says "virtual aid to navigation" if you select them.

I believe they're broadcast from the shore, presumably under the auspices of a CROSS or VTS station. I was seeing the one off Cherbourg a good ten miles to the north - possibly further, but I wasn't looking.

Incidentally, I have no idea what the purpose of these things is. If they want a virtual point in the sea, why not just mark it on charts instead of continuously broadcasting its position by radio?

Pete

 

[Cardo]

Mr Raymarine plotter shows the static buoy/lighthouse/etc. targets as diamonds. I've never seen one of these targets that isn't atop a physical structure, though.

Disclaimer - Not read the article, so I may be missing something.

 

[Bru]

I rather suspect that the long term goal of vAtoN (virtual Aids to Navigation) is to do away with physical buoys in many locations

You can see the attraction for the authorities - no more need to operate expensive buoy handling vessels, instant changes to "buoy" positions, reduced admin overhead disseminating NtMs etc

The point of these vAtoNs, by the way, is that there is nothing actually there, they simply show up on the plotter / AIS / ECDIS etc screen

For those of us who hate the thought of being reliant on electronics, the future is NOT looking too bright!!!!

 

[prv]

I've never seen one of these targets that isn't atop a physical structure, though.

I apply corrections to my paper charts each winter. As well as giving me warm fuzzies of being a Proper Navigator (even though I aren't), it's interesting to see what's changing (how many people realise that all the major Channel lighthouses are having their lights turned down a bit?)

Starting last winter (ie 2012/13), a number of corrections have been to remove buoys, mostly (or possibly exclusively) off the French coast, and replace them with virtual AIS symbols. The one most of us Solent folks would encounter is CH1, formerly a physical buoy in the approach to Cherbourg and now only an electronic broadcast. I made the correction this winter, and saw the target on the AIS display on Saturday.

(I haven't read the article either)

Pete

 

[RAI]

I thought the original intention of AIS vAtoN was to be able to place warning markers quickly and not have to wait for NOTAMS and manual chart updates. For example, placing cardinals around a new wreck.

 

[Cardo]

I apply corrections to my paper charts each winter. As well as giving me warm fuzzies of being a Proper Navigator (even though I aren't), it's interesting to see what's changing (how many people realise that all the major Channel lighthouses are having their lights turned down a bit?)

Starting last winter (ie 2012/13), a number of corrections have been to remove buoys, mostly (or possibly exclusively) off the French coast, and replace them with virtual AIS symbols. The one most of us Solent folks would encounter is CH1, formerly a physical buoy in the approach to Cherbourg and now only an electronic broadcast. I made the correction this winter, and saw the target on the AIS display on Saturday.

(I haven't read the article either)

Pete

Thanks for the info, good to know. I hope my AIS doesn't pack up!

 

[prv]

The point of these vAtoNs, by the way, is that there is nothing actually there, they simply show up on the plotter / AIS / ECDIS etc screen

Uh, yeah, I get that bit thanks.

But if they simply "printed" the thing on the electronic chart then it would also show up on the same screen, so why bother with the radio broadcast?

Understandable for instant "wreck buoys" etc, but for something like CH1 off Cherbourg or the deep-sea buoys off Ushant, which are permanent changes included in chart corrections etc, what does AIS give over a reporting-point or T-dashed line on the chart?

Pete

 

[richardbrennan]

For those that haven't read the article, there's supposed to be one marking the Bramble Pile. I have spoken to Digital Yacht who confirm that most plotters show these virtual marks as diamonds but were unable to confirm the situation specifically with regard to Garmin. They are obviously generated from elsewhere so the range is from the base station rather than the actual position of the mark. The stated objective is for the rapid marking of wrecks etc!

 

[prv]

For those that haven't read the article, there's supposed to be one marking the Bramble Pile.

And indeed there is, has been for at least a year now. Also "Calshot" (I assume the light-float, though I've never actually checked the position) and there have been two or three others in the area listed as "Trial AtoN".

The stated objective is for the rapid marking of wrecks etc!

And that makes sense. But it's not what the French are doing with them. They are replacing static, charted, hitherto-permanent buoys, with AIS artefacts that are themselves marked on the charts.

Pete

 

[johnalison]

The stated objective is for the rapid marking of wrecks etc!

I'm relieved to read this. I have wondered why one would need a virtual mark because if you need a virtual mark to know your position you would need to have a GPS to make use of this, in which case you would already know your position. I feel the same way about AIS shore marks, though I have no doubt that there is a logical explanation or they wouldn't waste the money.

 

[Colvic Watson]

It almost makes you hope for a bit of GPS outage, just to remind the authorities how ridiculous it is to rely on electronics alone.

 

[Bru]

Uh, yeah, I get that bit thanks.

But if they simply "printed" the thing on the electronic chart then it would also show up on the same screen, so why bother with the radio broadcast?

Understandable for instant "wreck buoys" etc, but for something like CH1 off Cherbourg or the deep-sea buoys off Ushant, which are permanent changes included in chart corrections etc, what does AIS give over a reporting-point or T-dashed line on the chart?

Pete

Good question!

Pity I don't know the answer

 

[nigelmercier]

... the individual I spoke to clearly thought that there would be something physical at the location generating the signal ...

Perhaps you would have been better talking to somebody who isn't an idiot.

 

[prv]

Perhaps you would have been better talking to somebody who isn't an idiot.

This is the problem with a company of any size - the punters are rarely allowed to talk directly to the people who actually know what's going on.

Pete

 

[Giblets]

The one most of us Solent folks would encounter is CH1, formerly a physical buoy in the approach to Cherbourg and now only an electronic broadcast.

Correct me if I'm wrong here, Pete, but are you saying that CH1 no longer exists in the form of a physical buoy? If that's the case then how do they get it to display the actual wind speed, direction & temperature?

 

[prv]

Correct me if I'm wrong here, Pete, but are you saying that CH1 no longer exists in the form of a physical buoy?

That is what I'm saying, though the source is not my own two eyes (I wasn't close enough at the weekend).

If you look at the bottom of page 3 of these corrections: https://www.ukho.gov.uk/Productsand...NMs/Folios/5604SC5604_The_Channel_Islands.pdf

you will find the buoy being replaced with a virtual aid (simply adding AIS to an existing structure is expressed differently, and anyway CH1 already had it).

See also items 13 and 17 in these Imray corrections: https://www.imray.com/files/chart_corrections/ICC10-1N.pdf?id=1399582183 , plus numerous others in which AIS is added to existing structures (the point being that they are different to 13 and 17 in which physical structures are replaced).

As I say, this is all a paper exercise not something I've observed first-hand, but those Ushant replacements were notified in 2012, so if they're wrong there's been plenty of time for it to be pointed out and it hasn't.

I didn't know CH1 did weather reports; perhaps they're now producing them from on land but keeping the same name?

Pete

 

[RIBW]

This is the problem with a company of any size - the punters are rarely allowed to talk directly to the people who actually know what's going on.
Pete

Pete, agreed! But, I would go one step further when slightly higher tech is the topic. My car's inbuilt GPS fails to calculate journey times with anything close to accuracy. My problem was eventually passed, reluctantly, to the 'guru'. His diagnosis was that I must have been breaking the speed limit! This clearly indicated he had no understanding of the system he was supporting nor any sense of customer care (i.e. accusing a customer of breaking the law!).

A few thoughts:-
It would be helpful if one of the magazines published an 'idiots' guide to the issue, which addressed both the technology and the politics.

I can sympathise with the desire to retain the traditional A2N, but costs have to be justified and funded. I'd rather have virtualA2N than no A2N. (Drawing on a crudely parallel situation, could a string of signalmen in remote boxes along the West Highland Railway Line still be afforded - they were replaced to save money by a successful radio based system in the late 80s).

If virtual A2Ns can be made very cheaply, they could be used, judiciously, to make entry to some harbours much safer.

Regards
Bob

 

[prv]

I'd rather have virtualA2N than no A2N. [...] If virtual A2Ns can be made very cheaply, they could be used, judiciously, to make entry to some harbours much safer.

If you think a virtual mark would make entry to some harbour easier, you don't need to wait for anybody to start broadcasting it. Take a pen to your paper chart, or add a waypoint to your electronic one, and you have precisely the same effect.

Pete

 

[RIBW]

If you think a virtual mark would make entry to some harbour easier, you don't need to wait for anybody to start broadcasting it. Take a pen to your paper chart, or add a waypoint to your electronic one, and you have precisely the same effect. Pete

Understood. Thinking more of those places with shifting entries (after storms etc), poorly charted or redimensioned fishfarms etc. The local harbour authority could make changes as necessary.
Bob