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  1.  NAME

  fix_nbr - Fix NB ADCP raw files

  2.  USAGE

  fix_nbr control_file

  3.  DESCRIPTION

  This utility can be used to fix recorded values in NB ADCP raw files.
  Currently, only fixing of ship's attitude is implemented.  See below
  for the syntax of the control file.

  4.  PARAMETERS

  The control file must contain the following parameters:

     year_base: YYYY
        Year base to use for conversion of time into decimal days. Note
        that since the NB ADCP raw format does not contain year
        information, this parameter should be set to year of data
        collections.

     file_list: file
        Name of a file containing the successive names of NB ADCP raw
        files to fix. This file can contain C-syntax comments.

     log_file: file
        File name for recording log information about fixing process.

     out_dir: directory
        Path to directory where fixed raw files should be written.

  5.  OPTIONS

  In addition to the parameters listed above, the following options are
  available:

     OPTIONS:
        This key word can be used to improve the clarity of the control
        file and specify the beginning of options. It has no effect.

     use_scan_nav_output:
        This method allows to fix NB ADCP raw files with processed
        navigation data resulting from scan_nav(1). The following sub-
        options are available:

        file_name: file
           Name of file containing fixes. The format of this file must
           be the same as the output of scan_nav(1).

        heading
           Must be specified if heading data have to be fixed.

        pitch
           Must be specified if pitch data have to be fixed.

        roll
           Must be specified if roll data have to be fixed.

        time
           Must be specified if time data have to be fixed.

        end
           This keyword is mandatory and terminates the list of selected
           sub-options.

     transducer_misalignment:
        This option can be used to correct NB ADCP raw files for
        misalignment of the transducer, in which case one or more of the
        following parameters must be specified:

        heading= heading_offset

        pitch=   pitch_offset

        roll=    roll_offset

        end
           This keyword is mandatory and terminates the list of selected
           sub-options.

        Values must be in degrees. The specified offset is subtracted
        from  the measured value to yield the expected correct value.
        These offsets are set to 0.0 by default.

     end
        This keyword is mandatory and terminates the list of selected
        options.

  If both method are selected, tilt corrections are performed on values
  from the external navigation file.

  6.  TIME RANGES

  Finally, the control file is terminated by a list of time ranges.  See
  time_rng(5) for the syntax of these.

  7.  OUTPUT FILES

  Generated fixed NB ADCP raw files have exactly the same name as input
  ones, except that they are located in the specified output directory.

  The log file contains information about fixing process, as well as
  reading status from the navigation file.

  8.  AUTHOR

  Pierre Jaccard, Geophysical Institute, University of Bergen, 1999



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