From a6292f2fd14a940f9b002338fe221543c7169bde Mon Sep 17 00:00:00 2001
From: Sivert Havso <sivert@havso.net>
Date: Thu, 3 Feb 2022 14:09:00 +0000
Subject: [PATCH 1/3] Update VTG.HPP for NMEA0183 ver 2.3 and later

---
 VTG.HPP | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/VTG.HPP b/VTG.HPP
index 6b20a7a..88f34e6 100644
--- a/VTG.HPP
+++ b/VTG.HPP
@@ -44,10 +44,11 @@ class VTG : public RESPONSE
       ** Data
       */
 
-      double TrackDegreesTrue{ 0.0 };
-      double TrackDegreesMagnetic{ 0.0 };
-      double SpeedKnots{ 0.0 };
-      double SpeedKilometersPerHour{ 0.0 };
+      double   TrackDegreesTrue{ 0.0 };
+      double   TrackDegreesMagnetic{ 0.0 };
+      double   SpeedKnots{ 0.0 };
+      double   SpeedKilometersPerHour{ 0.0 };
+      FAA_MODE FAAMode{ FAA_MODE::ModeUnknown };
 
       /*
       ** Methods

From 8ea77041ec125645fc0ce604e4f083742ec4b34f Mon Sep 17 00:00:00 2001
From: Sivert Havso <sivert@havso.net>
Date: Thu, 3 Feb 2022 14:11:28 +0000
Subject: [PATCH 2/3] Update VTG.CPP for NMEA0183 ver 2.3 and later

---
 VTG.CPP | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/VTG.CPP b/VTG.CPP
index 44a04ed..983cb50 100644
--- a/VTG.CPP
+++ b/VTG.CPP
@@ -65,12 +65,31 @@ bool VTG::Parse( SENTENCE const& sentence ) noexcept
    /*
    ** First we check the checksum...
    */
+   
+   int checksum_field = 9;
+
+   // Version 2.3 of the standard has things different
+
+   FAAMode = sentence.FAAMode(9);
+
+   if (FAAMode != FAA_MODE::ModeUnknown)
+   {
+       checksum_field = 10;
+   }
+
+   auto const check = sentence.IsChecksumBad(checksum_field);
 
-   if ( sentence.IsChecksumBad( 9 ) == NMEA0183_BOOLEAN::True )
+   if ( check == NMEA0183_BOOLEAN::True )
    {
        SetErrorMessage(STRING_VIEW("Invalid Checksum"));
        return( false );
-   } 
+   }
+
+   if (check == NMEA0183_BOOLEAN::NMEA_Unknown)
+   {
+       SetErrorMessage(STRING_VIEW("Missing Checksum"));
+       return(false);
+   }
 
    TrackDegreesTrue       = sentence.Double( 1 );
    TrackDegreesMagnetic   = sentence.Double( 3 );
@@ -108,6 +127,7 @@ VTG const& VTG::operator = ( VTG const& source ) noexcept
    TrackDegreesMagnetic   = source.TrackDegreesMagnetic;
    SpeedKnots             = source.SpeedKnots;
    SpeedKilometersPerHour = source.SpeedKilometersPerHour;
+   FAAMode                = source.FAAMode;
 
    return( *this );
 }

From 2e7edb57a97981a9fe0415417829843b939f35bc Mon Sep 17 00:00:00 2001
From: Sivert Havso <sivert@havso.net>
Date: Thu, 3 Feb 2022 14:13:47 +0000
Subject: [PATCH 3/3] Add missing assignment for FAA mode

---
 RMC.CPP | 1 +
 1 file changed, 1 insertion(+)

diff --git a/RMC.CPP b/RMC.CPP
index fd7f785..40a7949 100644
--- a/RMC.CPP
+++ b/RMC.CPP
@@ -163,6 +163,7 @@ RMC const& RMC::operator = ( RMC const& source ) noexcept
    Date                       = source.Date;
    MagneticVariation          = source.MagneticVariation;
    MagneticVariationDirection = source.MagneticVariationDirection;
+   FAAMode                    = source.FAAMode;
 
   return( *this );
 }