Talk:Automatic identification system

Additional Links

Hi! I'd like to suggest a link for this article: U.S Cost Guard page about A.I.S: http://www.navcen.uscg.gov/enav/ais/default.htm Maybe a link to the Wikipedia-article about ACARS? http://en.wikipedia.org/wiki/ACARS This is my first posting on Wikipeida.. I know I can edit the article itself... but to make sure I don't step on anybodys toes.. :-)

I understand and agree with the US Coastguard link - but why the ACARS link?

Added Coast Guard link. No toes stepped on! -- Muffuletta 19:24, 3 December 2005 (UTC)

Hi - Can I suggest an additional external link for live AIS data & maps from the port of Southampton in the UK: http://www.ais-live.co.uk/

Minor Edits

I added a few minor upgrades to the article, and also added a picture of an operations specialist managing vessel traffic using AIS and RADAR. Thought it might be helpful. April 13, 2006

SOLAS Link?

The "SOLAS" link, in the first section, points to something completely random, although still called SOLAS...

Thanks to user 81.99.38.3, who fixed this on November 19, 2006.

Links to Commercial / Subscription sites

I've removed the links to non-free AIS data websites and to providers of transponders. Please see the Links to avoid section of the style guide for more on why these links are discouraged. Davandron | Talk 23:38, 1 December 2006 (UTC)

AIS Range Question

I'd first like to say that I found the entry on AIS very informative and much better than just reading the manual. I'm a merchant mariner and I've noticed that we can pick up other vessels' AIS range from quite a long distance away (50+ Nautical Miles in some cases). On the wikipedia it says that it uses digital VHF which may be better than normal VHF but says that nominal range is around 20 miles. Does AIS "piggyback" with other vessels? In other words, when my AIS signal hits another ship does it carry the information that that other ship already has back to mine thereby making the range greater? Also, I notice that when ships are picked up farther away that the AIS picture only shows the MMSI number instead of the ship's name on our ECDIS. Why is this? If we get the signal why wouldn't all of the AIS information get to us? Aargh57 01:01, 8 January 2007 (UTC)

I can offer some potential answers to these questions:

• 50 miles?: If both the receive and transmit antenna are a significant distance above the water's surface, you'll get a longer line of sight. I don't have first hand experience, but 50 miles doesn't sound impossible.
• Piggyback: Nope, there is no retransmission of position data. I think there is a provision for safety-of-life messages (panpan/mayday) to be rebroadcast but I can't remember for sure.
• Only MMSI?: This sounds like your AIS display truncating info for ships such a long distance away. You are correct that if you receive any data it should also have all the AIS information. (At least how I understand the specification).

Hope this helps - Davandron | Talk 15:05, 8 January 2007 (UTC)