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Old 02-02-2017, 13:20   #31
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Re: Why AIS makes sense

I know that in the baltic sea (Finland) for example during winter with heavy ice conditions, buoys is not possible to keep in position due to the heavy drifting ice, but ate displayed correctly with the help of virtual AIS ATON buoys.

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Originally Posted by Dockhead View Post
I stand corrected -- thank you very much!

This has added to my knowledge

This:

http://www.eba.eu.com/site-documents...n-ais-aton.pdf

Seems to say that a "synthetic ATON" broadcasts from shore or another place, but reports real position and other data, received by other means from a real buoy.

It's a "virtual ATON" which does not report the real position of any navigational aid. These report reefs, wrecks, floating debris, etc., or buoys which do not exist physically.


I can't find any reference to the use of Virtual ATONs in cases where the buoy they are reporting, actually exists physically. I would think that this would be bad practice, but I would be interested to know more if someone has information.
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Old 02-02-2017, 15:01   #32
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Re: Why AIS makes sense

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Originally Posted by petter5 View Post
I know that in the baltic sea (Finland) for example during winter with heavy ice conditions, buoys is not possible to keep in position due to the heavy drifting ice, but ate displayed correctly with the help of virtual AIS ATON buoys.
When the buoys are out of the water, correct?

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Old 03-02-2017, 01:12   #33
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Re: Why AIS makes sense

At least when the buoys are out of water, I does not know if if this is "default" all year.

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When the buoys are out of the water, correct?

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Old 03-02-2017, 06:03   #34
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Re: Why AIS makes sense

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Originally Posted by petter5 View Post
At least when the buoys are out of water, I does not know if if this is "default" all year.
I've sailed the whole coast of Finland from the Archipelago Sea to the Russian border, several times. But only in summer. Never saw any ATONs, synthetic or otherwise.

I'm guessing they switch them off when real buoys are in the water.


Incidentally [thread drift warning], never sailed anywhere, where the actual buoyage deviated so much from charted buoyage, even on freshly updated charts, as Finland. Took me a while to get used to that. I guess they change them all the time in the process of taking them out of the water and putting them back in, and don't bother to issue Notices to Mariners.
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Old 03-02-2017, 06:30   #35
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Re: Why AIS makes sense

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Originally Posted by Dockhead View Post
I've sailed the whole coast of Finland from the Archipelago Sea to the Russian border, several times. But only in summer. Never saw any ATONs, synthetic or otherwise.

I'm guessing they switch them off when real buoys are in the water.
Couple years ago there were a handful round a windfarm on the way to the Kiel canal coming from SE. 1 real buoy, the rest virtual. No idea if the real buoy ais was transmitted from land or the buoy itself.

Also, there was a virtual for the basse brefort NCM but no real buoy llast year just before that lovely Anse St Martin anchorage just short of Cape De La Hague heading west. Which was a bit confusing -- "Where is it, must be round here somewhere...."
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Old 03-02-2017, 06:43   #36
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Re: Why AIS makes sense

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Originally Posted by conachair View Post
Couple years ago there were a handful round a windfarm on the way to the Kiel canal coming from SE. 1 real buoy, the rest virtual. No idea if the real buoy ais was transmitted from land or the buoy itself.

Also, there was a virtual for the basse brefort NCM but no real buoy llast year just before that lovely Anse St Martin anchorage just short of Cape De La Hague heading west. Which was a bit confusing -- "Where is it, must be round here somewhere...."
Yes, I've seen those. But never a virtual buoy referring to a real one.

Windfarms everywhere have ATONs -- seems to be standard procedure. Mostly real buoys, broadcasting their real position, in my experience. For example, the new windfarm near Brighton, which was positioned exactly to interfere with sailors trying to get up or down the Channel to or from the Dover Straits

Here's the actual product:

http://www.itonavaids.com/wind-farms...eacon/type-iis

Broadcasts real position, plus a message about whether the buoy is in position or not. Pretty cool.
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Old 03-02-2017, 06:46   #37
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Re: Why AIS makes sense

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Originally Posted by Dockhead View Post
I've sailed the whole coast of Finland from the Archipelago Sea to the Russian border, several times. But only in summer. Never saw any ATONs, synthetic or otherwise.

I'm guessing they switch them off when real buoys are in the water.


Incidentally [thread drift warning], never sailed anywhere, where the actual buoyage deviated so much from charted buoyage, even on freshly updated charts, as Finland. Took me a while to get used to that. I guess they change them all the time in the process of taking them out of the water and putting them back in, and don't bother to issue Notices to Mariners.
++++++++++

Code:
4.3.1 buoys removed for the winter seAson
Some buoys are removed for the winter season. These seasonal changes are not corrected in the register, and are thus not 
visible in the List of Lights. Seasonal and temporary changes are reported in Notices to Mariners. Some of the removed 
buoys are replaced by virtual AIS AtoNs during the winter.
This is an excerpt from the Finnish publication http://www.liikennevirasto.fi/docume...6-633fc4a804da

A look at todays Marinetraffic.com for part of Gulf of Bothnia confirms this.

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Old 06-02-2017, 03:20   #38
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Re: Why AIS makes sense

Should the ones we have be updated? In the manual? In the program symbols?
https://www.opencpn.org/wiki/dokuwik...ttons:ais:aton
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Old 08-02-2017, 21:28   #39
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Re: Why AIS makes sense

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Originally Posted by El Pinguino View Post
A number of virtual AIS tx can be seen below.... including Astrolabe Reef which is 13 miles offshore from Tauranga... no physical marks as are half tide rocks and shoals.. I imagine the TX comes from Motiti Island.. close south.

A pity Astrolabe wasn't marked in 2011....
Just came across this thread... yup, that's one of our virtual AtoN customers but they didn't deploy their system until after the Rena wreck. They now have one of our virtual AIS AtoN systems which is being used to mark a number of locations offshore of Tauranga including Astrolabe Reef, although it isn't physically located on Motiti. We've got quite a few of these virtual systems deployed around the world for all sorts of stuff.

We also make real AIS AtoN's too and with respect to the various comments about off position and whether it makes more sense to show the position of the buoy (and indicate off-position) or the assigned / charted position of the buoy is an interesting debate. At the last IALA conference I attended there was a discussion about this and we've since made changes to accommodate regional authorities testing some alternative scenarios. One that I like is when the AtoN determines it is off station it continues to transmit its own location with the off-position indicator but also starts to transmit a virtual AtoN in the assigned position. This way you don't run into the buoy (and the owner can find it), but you also continue to have electronic visibility of the assigned position. There's a few variants of this scheme that we are supporting for additional experimentation.

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Old 08-02-2017, 23:58   #40
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Re: Why AIS makes sense

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One that I like is when the AtoN determines it is off station it continues to transmit its own location with the off-position indicator but also starts to transmit a virtual AtoN in the assigned position. This way you don't run into the buoy (and the owner can find it), but you also continue to have electronic visibility of the assigned position.
Now THAT is a great usage of the AIS system. I really like the way it addresses both sides of the argument. Way to go, Jeff!

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Old 09-02-2017, 03:08   #41
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Re: Why AIS makes sense

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Originally Posted by jeffrobbins View Post
Just came across this thread... yup, that's one of our virtual AtoN customers but they didn't deploy their system until after the Rena wreck. They now have one of our virtual AIS AtoN systems which is being used to mark a number of locations offshore of Tauranga including Astrolabe Reef, although it isn't physically located on Motiti. We've got quite a few of these virtual systems deployed around the world for all sorts of stuff.......

Jeff
Excellent, Thank you.

Q1? So we are up to speed with Real and Virtual..... but is any authority out there using Synthetic AToNs or is it just an option 'in the book' that isn't used?

Q2? If Astrolabe isn't generated from Motiti does it come from The Mount?

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Old 09-02-2017, 19:13   #42
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Re: Why AIS makes sense

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Originally Posted by El Pinguino View Post
Q1? So we are up to speed with Real and Virtual..... but is any authority out there using Synthetic AToNs or is it just an option 'in the book' that isn't used?
There are lots of synthetics around the world and the US Coast Guard is now transmitting hundreds of them. A cool application from one of customers is they have a real AtoN placed in a critical area. They'll also have on shore several miles away one of our virtual shore stations monitoring traffic in that area and the shore station also monitors the real AtoN. If the real AtoN stops transmitting, the shore station creates a synthetic in its place. A neat backup in case of battery or solar panel failure on the real AtoN.

Quote:
Originally Posted by El Pinguino
Q2? If Astrolabe isn't generated from Motiti does it come from The Mount?
No, it is transmitting virtual AtoN's to mark seven hazard areas from a high location above Tauranga. They had existing infrastructure already there so that was a logical choice.
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