public static IGPSMessage Parse(string sentence)
{
IGPSMessage message = null;
int checksumIndex = sentence.IndexOf("*");
if (checksumIndex == -1)
{
throw new Exception("No checksum found");
}
if (checksumIndex == sentence.Length - 1)
{
throw new Exception("No checksum after marker");
}
string checksum = sentence.Substring(checksumIndex + 1, sentence.Length - checksumIndex - 1);
sentence = sentence.Substring(0, checksumIndex);
string[] messageFields = sentence.Split(new char[] { ',' });
if (messageFields == null || messageFields.Length == 0)
{
throw new Exception("No fields in the message");
}
switch (messageFields[0])
{
case "$GPGGA":
{
FixedDataMessage fdMessage = new FixedDataMessage();
fdMessage.Timestamp = ParseTime(messageFields[1]);
fdMessage.Latitude = messageFields[2];
fdMessage.NSIndicator = ParseChar(messageFields[3]);
fdMessage.Longitude = messageFields[4];
fdMessage.EWIndicator = ParseChar(messageFields[5]);
fdMessage.PositionFix = ParsePositionFixIndicator(messageFields[6]);
fdMessage.SatallitesUsed = messageFields[7];
ParseDouble(messageFields[8], out fdMessage.HDOP, out fdMessage.IsHDOPValid);
ParseDouble(messageFields[9], out fdMessage.MSLAltitude, out fdMessage.IsMSLAltitudeValid);
fdMessage.MSLAltitudeUnits = ParseChar(messageFields[10], out fdMessage.IsMSLAltitudeUnitsValid);
ParseDouble(messageFields[11], out fdMessage.GeoidSeperation, out fdMessage.IsGeoidSeperationValid);
fdMessage.GeoidSeperationUnits = ParseChar(messageFields[12], out fdMessage.IsGeoidSeperationUnitsValid);
ParseInt(messageFields[13], out fdMessage.AgeOfDifferentialCorrection, out fdMessage.IsAgeOfDifferentialCorrectionValid);
fdMessage.DifferentialReferenceStationId = messageFields[14];
message = fdMessage;
break;
}
}
return(message);
}
private GPSPosition ParsePosition(FixedDataMessage message)
{
GPSPosition position = new GPSPosition();
position.HasFix = (message.PositionFix != PositionFixIndicator.Invalid);
position.IsEstimate = (message.PositionFix == PositionFixIndicator.Estimated);
if (position.HasFix)
{
position.Latitude = Convert.ToDouble(message.Latitude.Substring(0, 2)) + (Convert.ToDouble(message.Latitude.Substring(2, 7)) / 60);
if (message.NSIndicator == 'S')
position.Latitude = -position.Latitude;
position.Longitude = Convert.ToDouble(message.Longitude.Substring(0, 3)) + (Convert.ToDouble(message.Longitude.Substring(3, 7)) / 60);
if (message.EWIndicator == 'W')
position.Longitude = -position.Longitude;
}
return position;
}
public static IGPSMessage Parse(string sentence)
{
IGPSMessage message = null;
int checksumIndex = sentence.IndexOf("*");
if (checksumIndex == -1)
{
throw new Exception("No checksum found");
}
if (checksumIndex == sentence.Length - 1)
{
throw new Exception("No checksum after marker");
}
string checksum = sentence.Substring(checksumIndex + 1, sentence.Length - checksumIndex - 1);
sentence = sentence.Substring(0, checksumIndex);
string[] messageFields = sentence.Split(new char[] { ',' });
if (messageFields == null || messageFields.Length == 0)
{
throw new Exception("No fields in the message");
}
switch (messageFields[0])
{
case "$GPGGA":
{
FixedDataMessage fdMessage = new FixedDataMessage();
fdMessage.Timestamp = ParseTime(messageFields[1]);
fdMessage.Latitude = messageFields[2];
fdMessage.NSIndicator = ParseChar(messageFields[3]);
fdMessage.Longitude = messageFields[4];
fdMessage.EWIndicator = ParseChar(messageFields[5]);
fdMessage.PositionFix = ParsePositionFixIndicator(messageFields[6]);
fdMessage.SatallitesUsed = messageFields[7];
ParseDouble(messageFields[8], out fdMessage.HDOP, out fdMessage.IsHDOPValid);
ParseDouble(messageFields[9], out fdMessage.MSLAltitude, out fdMessage.IsMSLAltitudeValid);
fdMessage.MSLAltitudeUnits = ParseChar(messageFields[10], out fdMessage.IsMSLAltitudeUnitsValid);
ParseDouble(messageFields[11], out fdMessage.GeoidSeperation, out fdMessage.IsGeoidSeperationValid);
fdMessage.GeoidSeperationUnits = ParseChar(messageFields[12], out fdMessage.IsGeoidSeperationUnitsValid);
ParseInt(messageFields[13], out fdMessage.AgeOfDifferentialCorrection, out fdMessage.IsAgeOfDifferentialCorrectionValid);
fdMessage.DifferentialReferenceStationId = messageFields[14];
message = fdMessage;
break;
}
}
return message;
}
