These things are the balls! I started picking them up in Puget Sound on my radar which also displays AIS targets. But they were not displaying on Coastal Explorer, so I let them know. On my boat AIS comes into CE via N2K, and it turns out the Rose Point guys had never been able to get a sample of these AtoN messages on N2K, so hadn't been able to implement them. It does, by the way, work fine if you have AIS coming into CE via 0183. So, I sent them an N2K trace.
Dial forward a month or so and I load up the latest update to CE and guess what? AtoNs are now showing. I love those guys. And best of all, I found there is yet another form of AtoN that I didn't know about. Weather buoys! In SE Alaska there are a number of them that continuously transmit the conditions at their location. No need to go on-line ot get current conditions - just look at your chart plotter. Very, very cool.