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Old 12-02-2017, 06:28   #16
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Re: AIS not showing vessel names.

Yes that's it the one stay at un know
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Old 12-02-2017, 06:31   #17
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Re: AIS not showing vessel names.

Yes that's it the one stay at unknown but on my primary Ais it does show the name of that specific target
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Old 12-02-2017, 06:43   #18
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Re: AIS not showing vessel names.

Name show in Findship app but I find the callsign is not a valid one.Click image for larger version

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Old 12-02-2017, 07:30   #19
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Re: AIS not showing vessel names.

More.......
It seems that MMSI 601853300 in your AIS list is reporting it's name in AIS message 19.
But.... What I can find is message 19 not decoded by OCPN!
Am I correct in this? If so: Why? - - Can anyone explain or give us more background--
Håkan
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Old 12-02-2017, 08:23   #20
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Re: AIS not showing vessel names.

Ivanm..
A small test hack into OCPN AIS decoder, to also read mess.19, gave me this:
Rather like yours, isn't it? The call sign is not included in message type 19, that's why you can't see it. And why this fisher is using message 19 I cant imaging.
Including decoding of also this AIS message in OCPN code is not a big task so I'm still curious why it's not already there.

@bcn @transmitterdan @nohal @all are you here? More "flesh on the bones" please?

Håkan
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Old 12-02-2017, 08:37   #21
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Re: AIS not showing vessel names.

I will try to go and put a Callsign on that Boat tomorrow and see what happen but there are more targets that don't show names, so to do this will not be the solution. Meanwhile I will leave it for those who know to fix.
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Old 12-02-2017, 10:02   #22
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Re: AIS not showing vessel names.

Ivanm
The normal messages to transmit for a class B target are 18 and 24. If done all normal data including vessel name, call sign and dimension are seen "everywhere". Why this vessel use message 19 and omits the other two is the first question and the main cause of the failure.
As said: message 19 does not include a call sign.
Håkan
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Old 12-02-2017, 10:18   #23
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Re: AIS not showing vessel names.

Here https://www.navcen.uscg.gov/?pageName=AISMessages one reads the following :

19 -- Extended Class B equipment position report
No longer required. Extended position report for Class B shipborne mobile equipment; contains additional static information

From the same documents I would expect to get Static data (=name) for Class B by a message type 24.
Håkan, as you have the source code already at hand, perhaps you might confirm this.

Hubert

Ps.: noticed that you have been faster...
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Old 12-02-2017, 10:32   #24
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Re: AIS not showing vessel names.

Hubert
Yes, message 18 and 24 are well covered in OCPN code, no problem.
I've never before heard of any vessel sending only message 19.
Do you agree that O shall:
> Not be prepared for a AIS transponder failure to omit mes. 18 and 24?
> Not decode message 19?
If not it's easy to PR my little hack to include mess 19 decoding.
Håkan
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Old 12-02-2017, 10:35   #25
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Re: AIS not showing vessel names.

Perhaps we should investigate a bit more into msg 19.

There should people that will know in more detail than us.
On the other hand having msg 19 decoded will not make harm neither.

Hubert
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Old 12-02-2017, 10:49   #26
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Re: AIS not showing vessel names.

Quote:
Originally Posted by Ivanm View Post
I will try to go and put a Callsign on that Boat tomorrow and see what happen but there are more targets that don't show names, so to do this will not be the solution. Meanwhile I will leave it for those who know to fix.
Ivanm
From your text I understand you have som kind of connections to the vessels using this "ONWA Ais transceivers".(From one of your earlier post.)
Try to get these gadgets to "act as normal" and send messages 18 and 24 instead of 19.
Håkan
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Old 12-02-2017, 11:07   #27
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Re: AIS not showing vessel names.

Yes I have access to some of the vessels but not all of them with Onwa transceivers. Will change this one and see what happen.
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Old 12-02-2017, 11:36   #28
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Re: AIS not showing vessel names.

Digging into the specs:

The latest version of the relevant standard is M.1371-5, date 2014-02
https://www.itu.int/dms_pubrec/itu-r...2-I!!PDF-E.pdf

Quote:
Class B AIS using carrier-sense TDMA (CSTDMA) technology, subsequently referred to as Class B “CS”.

2.1.2.1 Autonomous and continuous mode
An “autonomous and continuous” mode for operation in all areas transmitting Message 18 for scheduled position reporting and Message 24 for static data.
The Class B “CS” AIS should be able to receive and process messages at any time except during time periods of own transmission.
2.1.2.3 Interrogation mode
A “polling” or controlled mode where the Class B “CS” AIS responds to interrogations for Messages 18 and 24 from a Class A AIS or a base station. An interrogation overrides a silent period defined by Message 23 (see § 3.21, Annex 8).
A Class B “CS” AIS should not interrogate other stations.

In relation to Message type 19 (page 100):
Quote:
19-No longer required; Extended Class B equipment position report
Transmit ONLY as response on base station interrogation
Further down (p127)
Quote:
3.17 Message 19: Extended class B equipment position report
For future equipment: this message is not needed and should not be used. All content is covered by Message 18, Message 24A and 24B.
For legacy equipment: this message should be used by Class B shipborne mobile equipment.
Pretty clear. Msg 19 will be used by some legacy equipment when challenged/interrogated.
(Or perhaps always if implemented this way complying with a previous version of the standard)
Understanding this message type for compatibility reasons will not be wrong.

Hubert
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Old 12-02-2017, 14:10   #29
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Re: AIS not showing vessel names.

Hubert
OK - understood.
Conclusion:
The message should normally not be sent.
But if sent the information can not harm OCPN and it's users if received and decoded.
So I can make a PR to master and refer to this discussion. OK?
Håkan
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Old 12-02-2017, 14:15   #30
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Re: AIS not showing vessel names.

Would be my conclusion as well - so let us sink the vessel :-))
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