vb接收GPS数据源码全

p;     
            If Mid(MSComm1.Tag, 1, 6) = "$GPGGA" Then '''' GPS fix data
               ParseGPS_GPGGA MSComm1.Tag
            End If
            
            MSComm1.Tag = ""
         End If
      Else
         MSComm1.Tag = MSComm1.Tag & Mid(val, 1, 1)
      End If
      
   End If
End Sub


Public Function ParseGPS_GPGGA(sLine As String)
   '''' parses a NMEA GPGGA packet
   '''' Global Positioning System Fix Data. Time, position and fix related data for a GPS receiver.
   '''' eg1. $GPGGA,170834,4124.8963,N,08151.6838,W,1,05,1.5,280.2,M,-34.0,M,,,*75
   '''' eg2. $GPGGA,hhmmss.ss,ddmm.mmm,a,dddmm.mmm,b,q,xx,p.p,a.b,M,c.d,M,x.x,nnnn
   Dim lat_deg As Double, lon_deg As Double
   
   If Mid(sLine, 1, 9) <> "$GPGGA,,," Then '''' emply packet
      Checksum = GetToken(sLine, 2, "*")     '''' remove the * off
      sLine = GetToken(sLine, 1, "*")
          
      Dim lat_deg_nmea As Double
      Dim lon_deg_nmea As Double
      Dim altitude As Double
      Dim lat_dir As String
      Dim lon_dir As String
          utc_time = GetToken(sLine, 2, ",")  '''' hhmmss.ss = UTC of fix
      lat_deg_nmea = GetToken(sLine, 3, ",")  '''' ddmm.mmm = latitude of position
           lat_dir = GetToken(sLine, 4, ",")  '''' a = N or S, latitutde hemisphere
      lon_deg_nmea = GetToken(sLine, 5, ",")  '''' dddmm.mmm = longitude of position
           lon_dir = GetToken(sLine, 6, ",")  '''' b = E or W, longitude hemisphere
           quality = GetToken(sLine, 7, ",")  '''' q = GPS Quality indicator (0=No fix, 1=Non-differential GPS fix, 2=Differential GPS fix, 6=Estimated fix)
          &nb