/// <summary>
/// Extracts a full NMEA string from the data recieved on the serialport, and parses this.
/// The remaining and unparsed NMEA string is returned.
/// </summary>
/// <param name="strNMEA">NMEA ASCII data</param>
/// <returns>Unparsed NMEA data</returns>
private string GetNmeaString(string strNMEA)
{
strNMEA = strNMEA.Replace("\n", "").Replace("\r", ""); //Remove linefeeds
int nStart = strNMEA.IndexOf("$"); //Position of first NMEA data
if (nStart < 0 || nStart == strNMEA.Length - 2)
{
return(strNMEA);
}
//This will never pass the last NMEA sentence, before the next one arrives
//The following should instead stop at the end of the line.
int nStop = strNMEA.IndexOf("$", nStart + 1); //Position of next NMEA sentence
if (nStop > -1)
{
string strData = strNMEA.Substring(nStart, nStop - nStart).Trim();
if (strData.StartsWith("$"))
{
_hasTimedOut = false;
_timeSinceLastEvent = DateTime.Now.Ticks;
if (CheckSentence(strData))
{
FireEvent(GpsHandler.String2Eventtype(strData), strData);
}
}
return(strNMEA.Substring(nStop));
}
return(strNMEA);
}
public MainForm()
{
InitializeComponent();
Gps = new GpsHandler { TimeOut = 5 }; //Initialize GPS handler
Gps.NewGpsFix += GpsEventHandler; //Hook up GPS data events to a handler
FrmGpsSettings = new FrmGpsSettings();
}
/// <summary>
/// Responds to sentence events from GPS receiver
/// </summary>
private void GpsEventHandler(object sender, GpsHandler.GpsEventArgs e)
{
if (InvokeRequired)
{
// Execute the same method, but this time on the GUI thread
BeginInvoke(new ThreadStart(() => GpsEventHandler(sender, e)));
return;
}
tbRawLog.Text += e.Sentence + "\r\n";
if (tbRawLog.Text.Length > 20 * 1024 * 1024) //20Kb maximum - prevents crash
{
tbRawLog.Text = tbRawLog.Text.Substring(10 * 1024 * 1024);
}
tbRawLog.ScrollToCaret(); //Scroll to bottom
switch (e.TypeOfEvent)
{
case GpsEventType.GPRMC: //Recommended minimum specific GPS/Transit data
if (Gps.HasGpsFix) //Is a GPS fix available?
{
//lbRMCPosition.Text = GPS.GPRMC.Position.ToString("#.000000");
lbRMCPosition.Text = Gps.GPRMC.Position.ToString("DMS");
lbRMCCourse.Text = Gps.GPRMC.Course.ToString();
lbRMCSpeed.Text = Gps.GPRMC.Speed + " mph";
lbRMCTimeOfFix.Text = Gps.GPRMC.TimeOfFix.ToString("F");
lbRMCMagneticVariation.Text = Gps.GPRMC.MagneticVariation.ToString();
}
else
{
statusBar1.Text = "No fix";
lbRMCCourse.Text = "N/A";
lbRMCSpeed.Text = "N/A";
lbRMCTimeOfFix.Text = Gps.GPRMC.TimeOfFix.ToString();
}
break;
case GpsEventType.GPGGA: //Global Positioning System Fix Data
if (Gps.GPGGA.Position != null)
lbGGAPosition.Text = Gps.GPGGA.Position.ToString("DM");
else
lbGGAPosition.Text = "";
lbGGATimeOfFix.Text = Gps.GPGGA.TimeOfFix.Hour + ":" + Gps.GPGGA.TimeOfFix.Minute + ":" + Gps.GPGGA.TimeOfFix.Second;
lbGGAFixQuality.Text = Gps.GPGGA.FixQuality.ToString();
lbGGANoOfSats.Text = Gps.GPGGA.NoOfSats.ToString();
lbGGAAltitude.Text = Gps.GPGGA.Altitude + " " + Gps.GPGGA.AltitudeUnits;
lbGGAHDOP.Text = Gps.GPGGA.Dilution.ToString();
lbGGAGeoidHeight.Text = Gps.GPGGA.HeightOfGeoid.ToString();
lbGGADGPSupdate.Text = Gps.GPGGA.DGPSUpdate.ToString();
lbGGADGPSID.Text = Gps.GPGGA.DGPSStationID;
break;
case GpsEventType.GPGLL: //Geographic position, Latitude and Longitude
lbGLLPosition.Text = Gps.GPGLL.Position.ToString();
lbGLLTimeOfSolution.Text = (Gps.GPGLL.TimeOfSolution.HasValue ? Gps.GPGLL.TimeOfSolution.Value.Hours + ":" + Gps.GPGLL.TimeOfSolution.Value.Minutes.ToString() + ":" + Gps.GPGLL.TimeOfSolution.Value.Seconds.ToString() : "");
lbGLLDataValid.Text = Gps.GPGLL.DataValid.ToString();
break;
case GpsEventType.GPGSA: //GPS DOP and active satellites
if (Gps.GPGSA.Mode == 'A')
lbGSAMode.Text = "Auto";
else if (Gps.GPGSA.Mode == 'M')
lbGSAMode.Text = "Manual";
else lbGSAMode.Text = "";
lbGSAFixMode.Text = Gps.GPGSA.FixMode.ToString();
lbGSAPRNs.Text = "";
if (Gps.GPGSA.PRNInSolution.Count > 0)
foreach (string prn in Gps.GPGSA.PRNInSolution)
lbGSAPRNs.Text += prn + " ";
else
lbGSAPRNs.Text += "none";
lbGSAPDOP.Text = Gps.GPGSA.PDOP + " (" + DOPtoWord(Gps.GPGSA.PDOP) + ")";
lbGSAHDOP.Text = Gps.GPGSA.HDOP + " (" + DOPtoWord(Gps.GPGSA.HDOP) + ")";
lbGSAVDOP.Text = Gps.GPGSA.VDOP + " (" + DOPtoWord(Gps.GPGSA.VDOP) + ")";
break;
case GpsEventType.GPGSV: //Satellites in view
if (NMEAtabs.TabPages[NMEAtabs.SelectedIndex].Text == "GPGSV") //Only update this tab when it is active
DrawGSV();
break;
case GpsEventType.PGRME: //Garmin proprietary sentences.
lbRMEHorError.Text = Gps.PGRME.EstHorisontalError.ToString();
lbRMEVerError.Text = Gps.PGRME.EstVerticalError.ToString();
lbRMESphericalError.Text = Gps.PGRME.EstSphericalError.ToString();
break;
case GpsEventType.TimeOut: //Serialport timeout.
statusBar1.Text = "Serialport timeout";
break;
}
}