gsa.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: gsa.cpp $
** $Revision: 5 $
** $Modtime: 10/10/98 2:42p $
*/

#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

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

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

void GSA::Empty( void )
{
   OperatingMode = UnknownOperatingMode;
   FixMode       = FixUnknown;

   int index = 0;

   while( index < 12 )
   {
      SatelliteNumber[ index ] = 0;
      index++;
   }

   PDOP = 0.0;
   HDOP = 0.0;
   VDOP = 0.0;
}

BOOL GSA::Parse( const SENTENCE& sentence )
{
   /*
   ** GSA - GPS DOP and Active Satellites
   **
   **        1 2 3  4  5  6  7  8  9  10 11 12 13 14 15  16  17  18
   **        | | |  |  |  |  |  |  |  |  |  |  |  |  |   |   |   |
   ** $--GSA,a,x,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,x.x,x.x,x.x*hh<CR><LF>
   **
   ** Field Number: 
   **  1) Operating Mode, A = Automatic, M = Manual
   **  2) Fix Mode, 1 = Fix not available, 2 = 2D, 3 = 3D
   **  3) Satellite PRN #1
   **  4) Satellite PRN #2
   **  5) Satellite PRN #3
   **  6) Satellite PRN #4
   **  7) Satellite PRN #5
   **  8) Satellite PRN #6
   **  9) Satellite PRN #7
   ** 10) Satellite PRN #8
   ** 11) Satellite PRN #9
   ** 12) Satellite PRN #10
   ** 13) Satellite PRN #11
   ** 14) Satellite PRN #12
   ** 15) PDOP
   ** 16) HDOP
   ** 17) VDOP
   ** 18) Checksum
   */

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

   const NMEA0183_BOOLEAN checksum_is_bad = sentence.IsChecksumBad();

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

   CString field_data = sentence.Field( 1 );

   if ( field_data == TEXT( "A" ) )
   {
      OperatingMode = Automatic;
   }
   else if ( field_data == TEXT( "M" ) )
   {
      OperatingMode = Manual;
   }
   else
   {
      OperatingMode = UnknownOperatingMode;
   }

   int index = sentence.Integer( 2 );

   switch( index )
   {
      case 1:

         FixMode = FixUnavailable;
         break;

      case 2:

         FixMode = TwoDimensional;
         break;

      case 3:

         FixMode = ThreeDimensional;
         break;

      default:

         FixMode = FixUnknown;
         break;
   }

   index = 0;

   while( index < 12 )
   {
      SatelliteNumber[ index ] = sentence.Integer( index + 3 );
      index++;
   }

   PDOP = sentence.Double( 15 );
   HDOP = sentence.Double( 16 );
   VDOP = sentence.Double( 17 );

   return( TRUE );
}

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

   switch( OperatingMode )
   {
      case Manual:

         sentence += TEXT( "M" );
         break;

      case Automatic:

         sentence += TEXT( "A" );
         break;

      default:

         sentence += TEXT( "" );
         break;
   }

   switch( FixMode )
   {
      case FixUnavailable:

         sentence += TEXT( "1" );
         break;

      case TwoDimensional:

         sentence += TEXT( "2" );
         break;

      case ThreeDimensional:

         sentence += TEXT( "3" );
         break;

      default:

         sentence += TEXT( "" );
         break;
   }

   int index = 0;

   while( index < 12 )
   {
      if ( SatelliteNumber[ index ] != 0 )
      {
         sentence += SatelliteNumber[ index ];
      }
      else
      {
         sentence += TEXT( "" );
      }

      index++;
   }

   sentence += PDOP;
   sentence += HDOP;
   sentence += VDOP;

   sentence.Finish();

   return( TRUE );
}

const GSA& GSA::operator = ( const GSA& source )
{
   OperatingMode = source.OperatingMode;
   FixMode       = source.FixMode;

   int index = 0;

   while( index < 12 )
   {
      SatelliteNumber[ index ] = source.SatelliteNumber[ index ];
      index++;
   }

   PDOP = source.PDOP;
   HDOP = source.HDOP;
   VDOP = source.VDOP;

   return( *this );
}