/// <summary>
/// Adds a GPGSV sentence, and parses it.
/// </summary>
/// <param name="NMEAsentence">NMEA string</param>
/// <returns>Returns true if this is the last message in GSV nmea sentences</returns>
public bool AddSentence(string NMEAsentence)
{
bool lastmsg = false;
try
{
//Split into an array of strings.
string[] split = NMEAsentence.Split(new Char[] { ',' });
int satsInView = GPSHandler.intTryParse(split[3]);
int msgCount = GPSHandler.intTryParse(split[1]); //Number of GPGSV messages
int msgno = GPSHandler.intTryParse(split[2]); //Current messagenumber
if (msgCount < msgno || msgno < 1) //check for invalid data (could be zero if parse failed)
{
return(false);
}
if (msgno == 1)
{
_satellites.Clear(); //First message. Let's clear the satellite list
firstMessageParsed = true;
}
else if (!firstMessageParsed) //If we haven't received the first GSV message, return
{
return(false);
}
lastmsg = (msgCount == msgno); //Is this the last GSV message in the GSV messages?
int satsInMsg;
if (!lastmsg)
{
satsInMsg = 4; //If this isn't the last message, the message will hold info for 4 satellites
}
else
{
satsInMsg = satsInView - 4 * (msgno - 1); //calculate number of satellites in last message
}
for (int i = 0; i < satsInMsg; i++)
{
Satellite sat = new Satellite();
sat.PRN = split[i * 4 + 4];
sat.Elevation = Convert.ToByte(split[i * 4 + 5]);
sat.Azimuth = Convert.ToInt16(split[i * 4 + 6]);
Byte.TryParse(split[i * 4 + 7], out sat.SNR);
//sat.SNR = Convert.ToByte(split[i * 4 + 7]);
_satellites.Add(sat);
}
}
catch { }
return(lastmsg);
}
/// <summary>
/// Initializes the NMEA Global Positioning System Fix Data and parses an NMEA sentence
/// </summary>
/// <param name="NMEAsentence"></param>
public GPGGA(string NMEAsentence)
{
try
{
if (NMEAsentence.IndexOf('*') > 0)
{
NMEAsentence = NMEAsentence.Substring(0, NMEAsentence.IndexOf('*'));
}
//Split into an array of strings.
string[] split = NMEAsentence.Split(new Char[] { ',' });
if (split[1].Length >= 6)
{
TimeSpan t = new TimeSpan(GPSHandler.intTryParse(split[1].Substring(0, 2)),
GPSHandler.intTryParse(split[1].Substring(2, 2)), GPSHandler.intTryParse(split[1].Substring(4, 2)));
DateTime nowutc = DateTime.UtcNow;
nowutc = nowutc.Add(-nowutc.TimeOfDay);
_timeOfFix = nowutc.Add(t);
}
_position = new Coordinate(GPSHandler.GPSToDecimalDegrees(split[4], split[5]),
GPSHandler.GPSToDecimalDegrees(split[2], split[3]));
if (split[6] == "1")
{
_fixQuality = FixQualityEnum.GPS;
}
else if (split[6] == "2")
{
_fixQuality = FixQualityEnum.DGPS;
}
else
{
_fixQuality = FixQualityEnum.Invalid;
}
_noOfSats = Convert.ToByte(split[7]);
GPSHandler.dblTryParse(split[8], out _dilution);
GPSHandler.dblTryParse(split[9], out _altitude);
_altitudeUnits = split[10][0];
GPSHandler.dblTryParse(split[11], out _heightOfGeoid);
GPSHandler.intTryParse(split[13], out _dGPSUpdate);
_dGPSStationID = split[14];
}
catch { }
}