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.. UHDAS/CODAS restructured text document
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**Seapath** Diagnostics
--------------------------


Unfortunately, Seapath attitude messages ( ``$PSXN,23`)
do not include any quality informatoion.  UHDAS should
be configured to acquire ``$PSXN,20`` for quality assesment.



$PSXN,20 messages
~~~~~~~~~~~~~~~~~~~

* Example: Good quality attitude:

::


  $PSXN,20,1,0,0,0*3A
  $PSXN,20,1,0,0,0*3A
  $PSXN,20,1,0,0,0*3A
  $PSXN,20,1,0,0,0*3A
           ^ ^ ^ ^
           | | | |______ roll, pitch quality
           | | |
           | | |_________ heading quality
           | |
           | |___________ height quality
           |
           |______________ horizontal (position) quality
                           (apparently a 1 here is OK for UHDAS)


  quality for:  horizontal, height, heading, roll&pitch.
  quality: 0 = normal, 1 = reduced performance, 2 = invalid data

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* Example: Bad attitude:

::


  $PSXN,20,1,0,1,0*3B
  $PSXN,20,1,0,1,0*3B
  $PSXN,20,1,0,1,0*3B
  $PSXN,20,1,0,1,0*3B
               ^
               |_____________ reduced performance = BAD NEWS


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On a UHDAS computer, you can query the logging system to
see what the actual recent messages are by typing:

::

    showlast.py -a20


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