UHDAS Serial Inputs
~~~~~~~~~~~~~~~~~~~~~

UHDAS data files have a specific directory and filename convention.
During UHDAS data acquisition the serial data are timestamped and 
written to disk, and translated into a simple binary format.  VmDAS
ascii serial fiels (``N1R``, ``N2R``, ``N3R``) can also be translated
into this binary format.

(1) **RAW** 

Serial data are logged into the ``raw`` directory

      - each serial port gets its own subdirectory
      - the file suffix is an indicator of the contents
      - every line that is logged is timestamped by the computer

Example (for a POSMV): ``raw/posmv/km2011_202_07200.pmv``

(2) **RBIN**

Ascii serial data are translated into binary, in the ``rbin`` directory.
Each ascii serial stream (eg POSMV, GPS,...)  and each configured message
inside it, are translated into a binary files which can be read (or written)
by Python or Matlab.

      - each serial port gets its own subdirectory (parallel to ``raw``)
      - the NMEA message determines the file suffix


Example (for a POSMV): 

      - ``rbin/posmv/km2011_202_07200.pmv.rbin``  (for $PASHR message)
      - ``rbin/posmv/km2011_202_07200.gps.rbin``  (for $GPGGA message)



UHDAS file format

::

 km = ship letters
 2011 = year of data collection
 202 = zero-based integer day of year
 07200 = zero-based seconds of day
 pmv 'message' (see below)
 rbin = suffix for rbin data


**RBIN message name**


There is only one rbin message name for a given NMA string.
Typical UHDAS directory names are used below.  Given the 
NMEA message (left) and the presence or absence of a 
checksum, the message name is fixed. 


+--------------------+-----------+-----------+------------+
| NMEA string        | typical   | checksum? |  message   |
|                    | UHDAS     |           |  name      |
|                    | directory |           |            |
|                    | name      |           |            |
+====================+===========+===========+============+
| $GPGGA             | gpsnav    |   yes     |   gps      |
+--------------------+-----------+-----------+------------+
| $INGGA             | gpsnav    |   yes     |   gps      |
+--------------------+-----------+-----------+------------+
| $GPGGA             | gpsnav    |   no      |   ggn      |
+--------------------+-----------+-----------+------------+
| $INGGA             | gpsnav    |   no      |   ggn      |
+--------------------+-----------+-----------+------------+
| $HEHDT             | gyro      |   yes     |   hdg      |
+--------------------+-----------+-----------+------------+
| $HEHDG             | gyro      |   yes     |   hdg      |
+--------------------+-----------+-----------+------------+
| $HEHDT             | gyro      |   no      |   hnc      |
+--------------------+-----------+-----------+------------+
| $HEHDG             | gyro      |   no      |   hnc      |
+--------------------+-----------+-----------+------------+
| $PASHR,ATT         | ashtech   |   yes     |   adu      |
+--------------------+-----------+-----------+------------+
| $PASHR,AT2         | ashtech   |   yes     |   at2      |
+--------------------+-----------+-----------+------------+
| $PASHR,PAT         | ashtech   |   yes     |   pat      |
+--------------------+-----------+-----------+------------+
| $GPPAT             | ashtech   |   yes     |   paq      |
+--------------------+-----------+-----------+------------+
| $PASHR             | posmv     |   yes     |   pmv      |
+--------------------+-----------+-----------+------------+
| $PRDID             | heading   |   yes     |   rdi      |
+--------------------+-----------+-----------+------------+
| $PSXN,20+$PSXN,23  | seapath   |   yes     |   sea      |
+--------------------+-----------+-----------+------------+
| $GPGGA+$PSXN,20    | seapath   |   yes     |   gps_sea  |
+--------------------+-----------+-----------+------------+
| $PSAT,HPR          |   csi     |   yes     |   psathpr  |
+--------------------+-----------+-----------+------------+
| : (tss1)           |  mahrs    |   yes     |   tss1     |
+--------------------+-----------+-----------+------------+
| : (tss1)           |  mahrs    |   no      |   hnc_tss1 |
+--------------------+-----------+-----------+------------+

CODAS Python processing must be configured so it can
find appropraite instrument+message pairs for position,
reliable heading, and a heading correction device (if present).