rmc.cpp

提取各种NEMA0183格式数据的类编程。

/*
** Author: Samuel R. Blackburn
** Internet: [e-mail]
**
** Copyright, 1996-2005, Samuel R. Blackburn
**
** "You can get credit for something or get it done, but not both."
** Dr. Richard Garwin
**
** BSD License follows.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** Redistributions of source code must retain the above copyright notice,
** this list of conditions and the following disclaimer. Redistributions
** in binary form must reproduce the above copyright notice, this list
** of conditions and the following disclaimer in the documentation and/or
** other materials provided with the distribution. Neither the name of
** the WFC nor the names of its contributors may be used to endorse or
** promote products derived from this software without specific prior
** written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**
** $Workfile: rmc.cpp $
** $Revision: 5 $
** $Modtime: 10/12/98 6:43a $
*/

#include "nmea0183.h"
#pragma hdrstop

#if defined( _DEBUG ) && defined( _INC_CRTDBG )
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#define new DEBUG_NEW
#endif // _DEBUG

RMC::RMC()
{
   Mnemonic = TEXT( "RMC" );
   Empty();
}

RMC::~RMC()
{
   Mnemonic.Empty();
   Empty();
}

void RMC::Empty( void )
{
   UTCTime.Empty();
   IsDataValid                = NMEA_Unknown;
   SpeedOverGroundKnots       = 0.0;
   Position.Empty();
   TrackMadeGoodDegreesTrue   = 0.0;
   Date.Empty();
   MagneticVariation          = 0.0;
   MagneticVariationDirection = EW_Unknown;
   FAAMode                    = FAAModeUnknown;
}

BOOL RMC::Parse( const SENTENCE& sentence )
{
   /*
   ** RMC - Recommended Minimum Navigation Information
   **                                                            12
   **        1         2 3       4 5        6 7   8   9    10  11|
   **        |         | |       | |        | |   |   |    |   | |
   ** $--RMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,xxxx,x.x,a*hh<CR><LF>
   **
   ** Field Number: 
   **  1) UTC Time
   **  2) Status, V = Navigation receiver warning
   **  3) Latitude
   **  4) N or S
   **  5) Longitude
   **  6) E or W
   **  7) Speed over ground, knots
   **  8) Track made good, degrees true
   **  9) Date, ddmmyy
   ** 10) Magnetic Variation, degrees
   ** 11) E or W
   ** 12) Checksum
   */

   /*
   ** First we check the checksum...
   */

   const NMEA0183_BOOLEAN checksum_is_bad = sentence.IsChecksumBad();

   if ( checksum_is_bad == True )
   {
      InvalidChecksum();
      return( FALSE );
   } 

   UTCTime                    = sentence.Field( 1 );
   Time                       = sentence.Time( 1 );
   IsDataValid                = sentence.Boolean( 2 );
   Position.Parse( 3, 4, 5, 6, sentence );
   SpeedOverGroundKnots       = sentence.Double( 7 );
   TrackMadeGoodDegreesTrue   = sentence.Double( 8 );
   Date                       = sentence.Field( 9 );
   MagneticVariation          = sentence.Double( 10 );
   MagneticVariationDirection = sentence.EastOrWest( 11 );

   const int checksum_field_number = sentence.ChecksumFieldNumber();

   if ( checksum_field_number == 13 )
   {
      FAAMode = sentence.FAAMode( 12 );
   }
   else
   {
      FAAMode = FAAModeUnknown;
   }

   return( TRUE );
}

CString RMC::ToText( void ) const
{
   CString return_string;

   return_string.Empty();

   return_string = TEXT( "At " );
   return_string += Time.Format( TEXT( "%I:%M.%S %p" ) );
   return_string += TEXT( " UTC, you were at " );
   return_string += Position.ToText();
   return_string += TEXT( ", making " );

   CString temp_string;

   temp_string.Format( TEXT( "%.2lf" ), SpeedOverGroundKnots );

   return_string += temp_string;
   return_string += TEXT( " knots, track made good " );

   temp_string.Format( TEXT( "%.2lf" ), TrackMadeGoodDegreesTrue );
   return_string += temp_string;
   return_string += TEXT( " degrees true." );

   return( return_string );
}

BOOL RMC::Write( SENTENCE& sentence )
{
   /*
   ** Let the parent do its thing
   */
   
   RESPONSE::Write( sentence );

   sentence += UTCTime;
   sentence += IsDataValid;
   sentence += Position;
   sentence += SpeedOverGroundKnots;
   sentence += TrackMadeGoodDegreesTrue;
   sentence += Date;
   sentence += MagneticVariation;
   sentence += MagneticVariationDirection;

   sentence.Finish();

   return( TRUE );
}

const RMC& RMC::operator = ( const RMC& source )
{
   UTCTime                    = source.UTCTime;
   Time                       = source.Time;
   IsDataValid                = source.IsDataValid;
   Position                   = source.Position;
   SpeedOverGroundKnots       = source.SpeedOverGroundKnots;
   TrackMadeGoodDegreesTrue   = source.TrackMadeGoodDegreesTrue;
   Date                       = source.Date;
   MagneticVariation          = source.MagneticVariation;
   MagneticVariationDirection = source.MagneticVariationDirection;

  return( *this );
}