Re: xgps & AIS Data

[Gary E. Miller]

Yo Владимир!

On Tue, 14 Apr 2020 01:02:48 +0300
Владимир Калачихин <address@hidden> wrote:

> Hi Gary!
> 13.04.2020 23:18, Gary E. Miller пишет:
> >> Sorry, it is a "Static & Voyage Data", and it is correct.  
> > 
> > That was also my understanding from the standard (Rec. ITU-R
> > M.1371-4)
> > 
> > So this still looks wrong to you?  
> 
> No. It looks like right.
> However, the client application will need to collect several messages 
> (by mmsi) to get full information about a specific vessel. It doesn't 
> look very elegant.

I agree a good AIS client should.  But gpsd has no good AIS client now.
Patches welcome.


> > Here is doc on message 8, doc 200, fi 10:
> > http://www.e-navigation.nl/content/inland-ship-static-and-voyage-related-data
> > 
> > I'm not sure how to read that...
> > 
> > Looks like shiptype is 14 bits.
> >   
> This may not be true.
>  From this: https://www.navcen.uscg.gov/?pageName=AISMessage8
> 
> "Since the data content of this binary message is defined by the 
> application, Message 8 is an Application Specific Message"

Yes, and the application specific decode was given by the URL I gave.

> Perhaps this message should not be decoded at all.

The decode looks good to me.  And you have not noted any doc that says
otherwise.  I'll happily hide data that is badly decoded, bug good data
is good.

So unless you can document a defect in the sample you sent, we'll have
to agree it looks correct.

The next questions would be if you still think xpgs is doing something
wrong?  As opposed to no doing enough.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
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