AIS question...

[Rtaylor]

I'm at sea at the moment and revising for my orals. I got to talking with the 3/O about the AIS and potentially using base stations for position fixing. Given that they are stationary and therefor don't require a GPS signal, what does the MCA about using distance and bearing to these to fix position on a chart?

Robert

[Steve]

With what means have you established your position relative to the base station?

[Pilot Chris]

Its always worth remembering that it will still be dependant on the quality of your GPS signal thus an error is always possible, I would stick my neck out and say that the MCA probably would not like it as variables such as heading data and the quality of the "SOTDMA's (Self organised time data multiple Acess system) may in fact be off (Although class A it shouldnt be)

[gadget123]

Seeing as your position relative to the base station is GPS based it would be more accurate just to plot your GPS position directly as there are less errors involved.

However using the AIS aids to navigation to identify a light/buoy and then using the bouy/lights radar echo for position fixing can be a useful tool.

[Pilot Chris]

I wouldnt go talking about fixing off buoys in any orals! could lead to a "thank you Mr/Mrs .... I suggest you get some more seatime!)

However using the AIS aids to navigation to identify a light/buoy and then using the bouy/lights radar echo for position fixing can be a useful tool.

[EH75]

Haha during my cadetship we were constantly fixing the positron off of buoys. They loved doing that. For the record, I am aware that this is not a good idea.

[Steve]

For the record, I am aware that this is not a good idea.

Depends on what else is available. If cross-referencing with GPS you can a) help to confirm your GPS derived position and b) recognise when a buoy is out of position.

[size4riggerboots]

If it's a fixed AIS station, i.e not a floating buoy but a tower structure, then it's perfectly fine to use it to get a range and bearing fix on. You wouldn't use the AIS information to plot it, but could positively identify it with the AIS and then get a radar range and bearing to put on the chart.

[Rtaylor]

Thanks, that is pretty well what I was looking for.

[Martyboy]

I think I said in another thread....... everyone loves a good Racon for position fixing these days

[laura]

Most of my shipmates don't learn morse these days.. got to say though I like a racon I do- fantastic when sailing up and down the Norwegian coast.

[Martyboy]

Signals is a soul destroying subject, although once you learn it you don't really forget it I like a good racon myself, I just wonder why people wont use a buoy to position fix unless it has a Racon on it