Synthetic AIS Navaids?

[rgano]

I haven't been paying a lot of attention to the Navaid world, and this announcement in my Local Notice to Mariners caught my attention. Perhaps one of you more informed types can give us all a primer on this. Here's the NOTAM:

QUOTE
In order to accommodate dredging operations, the U.S. Coast Guard has temporarily established Synthetic Automatic Identification System (AIS)
Aids to Navigation in the Pensacola Bay Entrance Channel for the following federal aids:
Pensacola Bay Entrance Lighted Buoy 9 (LLNR-4755) in approximate position 30-18-55.740N 087-18-32.580W, with MMSI 993682444.
Pensacola Bay Entrance Lighted Buoy 12 (LLNR-4820) in approximate position 30-19-42.060N 087-18-28.020W, with MMSI 993682439.
Mariners are advised to exercise caution when transiting the area.

UNQUOTE

Does this herald the new era in which you would be silly yo not have AIS receive displayed on your chatplotter?

 

[delirious duo]

Wtf new regulations must be coming on classes of transponders! Any bets?

 

[tiltrider1]

I think what they are saying is that the aids have been removed and an AIS signal is being broadcasted to place an icon on your chart plotter at the appropriate place.

 

[rgano]

That's what I thought when I saw the notice, but all those outboard powered boats running out the channel for a day of fishing won't see it because few I have ever encountered bother with AIS of any sort. I know the one I go out on with my neighbor is so non-equipped.

 

[delirious duo]

IMO it smells like approved non standard gps approaches style creep in the same way aircraft folks fell into.

 

[oguidry]

Probably worth reading the introductory section of the Light List.

AIS-ATON message broadcast from a transponder affixed to the corresponding buoy and beacon.
Synthetic AIS-ATON: AIS ATON message broadcast (typically from shore) to an assigned position with a corresponding buoy or beacon.
Virtual AIS-ATON: AIS ATON message broadcast (typically from shore) to an assigned position with no corresponding buoy or beacon.

Both real and virtual AIS ATON are becoming increasing common on the East Coast.

 

[rslifkin]

AIS ATONs that match up to actual buoys function like an improved version of a RACON (improved in the sense that AIS can convey more information and is a bit simpler to use for this purpose).

AIS ATONs with no corresponding buoy are useful as long as it's not taken as an excuse to go crazy with removing buoys. But for buoys that would need to be moved frequently or a location where you'd want a navaid but can't feasibly place one, they seem pretty useful.

 

[psneeld]

I think I remember the first virtual AIS ATONs appearing about 8-10 years ago.... after a storm washed away a few sea buoys and the USCG set up virtual ones as a quick remedy... whether those buoys were ever replaced or supplemented with real ones I have no idea.

They were and I bet current virtual ATONs were/are not a huge factor for small boats as they usually mark shipping level ATON.

 

[twistedtree]

Probably worth reading the introductory section of the Light List.

AIS-ATON message broadcast from a transponder affixed to the corresponding buoy and beacon.
Synthetic AIS-ATON: AIS ATON message broadcast (typically from shore) to an assigned position with a corresponding buoy or beacon.
Virtual AIS-ATON: AIS ATON message broadcast (typically from shore) to an assigned position with no corresponding buoy or beacon.

Both real and virtual AIS ATON are becoming increasing common on the East Coast.

Thanks for pointing out the distinction. "Synthetic" AIS ATON makes a lot of sense for the Pensacola project, making it easier for people to locate the buoys as they get moved around.

There are a number of "Virtual" AIS ATON's in Puget sound. In fact, I think all the VTS traffic lane buoys are virtual at this point.

 

[tiltrider1]

Thanks for pointing out the distinction. "Synthetic" AIS ATON makes a lot of sense for the Pensacola project, making it easier for people to locate the buoys as they get moved around.

There are a number of "Virtual" AIS ATON's in Puget sound. In fact, I think all the VTS traffic lane buoys are virtual at this point.

Many of the VTS buoys in the PS are now virtual but not all of them. I suspect damaged VTS buoys will be replaced virtually and not physically.

 

[Serene]

We see the virtual ATONs in Australia typically on shifting sandbar entrances where they are used to show the best way across the bar, which may not correspond to the physical marks. e.g. buoys and leads.

 

[DDW]

I think the idea was invented by Stan Honey as virtual marks for the A-Cup races in SF Bay in 2013. The Coast guard liked the idea and it is getting more popular. Certainly a lot cheaper than buoys, a single cheap transmitter can represent dozens of ATONs. And they don't go off position or go missing. But also, not much use in a power outage, yours or theirs.

 

[Portage_Bay]

Without doubt maintaining virtual AIS ATONS is less expensive than physical ATONS. And synthetic ATONS can be useful in rapidly changing situations.

Add in that we all (mostly all) are now navigating by GPS and electronic plotter being able to "position" the ATON accurately at all times without need for updates on electronic chart files or paper charts is very valuable.

The downside I see for us recreational boaters is we will need to be fitted with AIS and should have redundant systems. Which is not bad really.

As for the smaller boats not likely equipped with AIS that is indeed unfortunate and another example of how the commercial user is being well supported without regard for recreational boaters.

I do recall the first time I encountered virtual ATONS approaching San Francisco VTS. The buoys were on the charts, both paper and plotter. But I couldn't confirm them with eyeballs or radar.

To say the least I was confused. But that was on me for not preparing well.

 

[slowgoesit]

The trend toward more and more "virtual" ATONs IMHO is having a bad unintended consequence. More and more, people are fixating on what is going inside the cabin, and less and less on what is actually going on OUTSIDE, in the real world! How many times have people had near misses, or actual collisions and their excuse was: "Nothing showed up on my AIS! How could I have run into anything?"

 

[Portage_Bay]

Good point. I first noticed this years ago when GPS and plotters became common place. I had a mate who had is face in the plotter all the time. We were working on the lower Columbia River on the Washington side across the river from the main channel below the Astoria Megler bridge at the time. When I got fed up asking him to look out the windows I covered the plotter screen and asked him "Where are we? How do you get safely to the main channel from here?" He couldn't answer either question and finally understood why I wanted him to not focus on the plotter so much.

The trend toward more and more "virtual" ATONs IMHO is having a bad unintended consequence. More and more, people are fixating on what is going inside the cabin, and less and less on what is actually going on OUTSIDE, in the real world! How many times have people had near misses, or actual collisions and their excuse was: "Nothing showed up on my AIS! How could I have run into anything?"

 

[CaptTom]

The reality is the ATON system has been designed for commercial interests all along. Aids which only apply to recreational boaters are kind of an afterthought, budget-wise.

I'm not sure I mind that. Frankly, the small boat day fishermen generally have no problem buying high-end reels and expensive fish finders. A decent chart plotter isn't too much to expect these days. Even a cell phone app will give them more information than we ever had back when marine electronics meant a VHF radio with crystals and one of those depth sounders with the rotating red lights.

I do see the problem of people accustomed to looking at screens all day forgetting to look out the window occasionally. But that problem doesn't exist only on the water.

 

[MichaelD]

There are three types of these synthetic ATONs:

1. a physical marker (buoy, beacon, etc.) with an actual transmitting AIS antenna.
2. A physical marker that is also marked by a synthetic AIS signal broadcast via shore towers showing the same location
3. Completely virtual ATONs with no physical marker, only a broadcast AIS beacon.

I don't believe there are many of any of these yet. Here in Salish sea I only know of one off of Everett.