Another AIS Class B glitch, & a parser in a pear tree
When Class B AIS finally gets going, there’ll be yet another issue to deal with: not all existing AIS plotting systems are going to fully understand the Class B messages. Apparently separate messages were anticipated in the original Class A standard but the slotting and details were changed in the final B standard that went official just this spring. I understand that the dynamic data—position, speed, etc.—will likely show, but the static stuff—boat name, etc.—may not until the plotter, ECDIS, radar, or whatever is updated.
A good place to see exactly how AIS messages are structured is Brian Lane’s AISparser.com. Among other resources is a neat demo that let’s you turn your own raw AIS strings into targets plotted in Google Earth. Brian is even running a sort of Christmas sale on his AISparser SDK, which I’d guess to be quite good. (Imagine the look on her face!)
And here’s some more good/bad B news: An AIS expert at the U.S. Coast Guard told me that two of the Class B transponders now awaiting USCG approval will “retail for under $900”. But he could not say whose, or when approvals may be issued. Neither could the FCC.
That is exactly right. Without sample [approved] Class B transponder messages to test with yet it makes it difficult to support at this time. Class A messages are formatted a bit different then Class B so what ever AIS plotting software you use will have to be updated to support the approved B messages. That being said I am most interested in Class A as Class B is going to be a lot of clutter.
The changes to the Class B static data messages (24A and 24B) are not really new – the standard was approved for publication in August 2005, so manufacturers have had over a year to get their software updated (assuming that they take an active interest in the standards process – but even if they don’t, it has been publiclly available since April 2006 – how slow can they go?).
I’ve heard that from a few people, Del, and don’t doubt it; but I do wonder how many Class A transponders, even recreational AIS plotters, have been updated to understand 24A & B?