bugGPSD - Bugs: bug #48260, Incorrect decoding of AIS Type 24...

 
 

bug #48260: Incorrect decoding of AIS Type 24 message

Submitter:  None
Submitted:  Fri 17 Jun 2016 10:39:57 PM UTC
   
 
Category:  None Severity:  3 - Normal
Item Group:  None Status:  Fixed
Privacy:  Public Assigned to:  None
Open/Closed:  Closed
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Thu 07 Sep 2017 11:38:35 AM UTC, comment #3: 

I forget that it is possible to enanle seeing these partial messages with the split24 JSON option.

Eric S. Raymond <esr>
Group administrator
Wed 06 Sep 2017 01:29:18 AM UTC, comment #2: 

The fact that message halves will not be decoded separately is a documented safety feature to avoid passing garbage to client applications.

Marking this "Won't Fix".

Eric S. Raymond <esr>
Group administrator
Fri 17 Jun 2016 11:44:50 PM UTC, comment #1: 

Another not decoded message

 Message 24 - Class B/CS Static Data Report - Part B
!AIVDM,1,1,,B,H3ch3N4TC9=B1409APpppj1@2220,0*39

Parm#   ↓ Parameter   ↓ Value   ↓ Description   ↓
01 Message ID 24
02 Repeat indicator 0
03 User ID (MMSI) 247202680
04 Message part number 1 1 = Part B
05 Type of ship & cargo 36 Sailing
06 Vendor ID SIMRAD@
07 Call sign IQ 8882
08 Ship dimensions A=10,B=2,C=2,D=2
09 Spare 0

If I try to decode them separately - I get nothing. But when I have two strings - part A then part B - they decodes into one message.

Anonymous
Fri 17 Jun 2016 10:39:57 PM UTC, original submission:  

I have an AIS Message of Type 24:
!AIVDM,1,1,,B,H3ch3N1=V18u<EA@61=KC;G4000,2*3E

It is correctly decoded by Schwehr's libais and Maritec decoder, but gpsdecode silently return empty string.
Here is output from Maritec decoder:

 Message 24 - Class B/CS Static Data Report - Part A
!AIVDM,1,1,,B,H3ch3N1=V18u<EA@61=KC;G4000,2*3E

Parm#   ↓ Parameter   ↓ Value   ↓ Description   ↓
01 Message ID 24
02 Repeat indicator 0
03 User ID (MMSI) 247202680
04 Message part number 0 0 = Part A
05 Name SY ROSETTA SV4251@@@

Anonymous

 

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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2017-09-07 esr StatusWont Fix Fixed
        Open/ClosedOpen Closed
    2017-09-06 esr StatusNone Wont Fix

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