/// <summary>
/// Parses a raw NMEA GSA (gps fix information) sentence.
/// This is the prefered sentence to use for positions.
/// It is only generated by NMEA 2.0 GPS units. All modern units should be version 2.0 complient.
/// </summary>
/// <remarks>
/// GSA - essential fix data which provide 3D location and accuracy data.
/// $GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39
/// Where:
/// GSA Satellite status
// A Auto selection of 2D or 3D fix(M = manual)
// 3 3D fix - values include: 1 = no fix
// 2 = 2D fix
// 3 = 3D fix
// 04,05... PRNs of satellites used for fix(space for 12)
// 2.5 PDOP(dilution of precision)
// 1.3 Horizontal dilution of precision(HDOP)
// 2.1 Vertical dilution of precision(VDOP)
// *39 the checksum data, always begins with*
/// </remarks>
/// <param name="sentence">NMEA GGA Senetence.</param>
/// <returns>True if the sentence is successfully parsed.</returns>
public bool ParseGSA(string sentence)
{
bool success = true;
// The sentence should be a comma seperated list of values
// Some may be empty!
// Start by stripping the leading and trailing data.
Char[] splitChars = { ',' };
//string[] words = sentence.Substring(1, sentence.IndexOf('*')).Split(splitChars, StringSplitOptions.None);
string[] words = sentence.Split(splitChars, StringSplitOptions.None);
// save the sentence type
mTag = words[0];
// Do we have enough words to parse the fix status?
if (words.Length > 2 && words[2].Length != 0)
{
// Get the fix code
mNMEAMode = words[2].Equals("1", StringComparison.OrdinalIgnoreCase) ? NMEAMODE.NO_FIX : (words[2].Equals("2", StringComparison.OrdinalIgnoreCase) ? NMEAMODE.TWO_DIMENSION : NMEAMODE.THREE_DIMENSION);
}
else
{
// The fix status is invalid
mNMEAMode = NMEAMODE.NO_MODE;
success = false;
}
return(success);
}
/// <summary>
/// Diseminates NMEA2000 Position, Rapid Update CAN frames.
/// </summary>
/// <remarks>
/// Position, Rapid Update PGN 129025
/// First two bytes of a NMEA2000 frame indicate the
/// <field>
/// name = "Latitude"
/// type = "int"
/// offset = "0"
/// length = "32"
/// signed = "yes"
/// units = "deg"
/// scaling = "0.0000001"
/// </field>
/// <field>
/// name = "Longitude"
/// type = "int"
/// offset = "32"
/// length = "32"
/// signed = "yes"
/// units = "deg"
/// scaling = "0.0000001"
/// </field>
/// </remarks>
public void ParsePositionRapidUpdate(byte[] data)
{
if (!BitConverter.IsLittleEndian)
{
Array.Reverse(data, 0, 4);
Array.Reverse(data, 4, 4);
}
double lat = BitConverter.ToInt32(data, 0);
lat *= 0.0000001;
double lon = BitConverter.ToInt32(data, 4);
lon *= 0.0000001;
mPosition.Reset(lat, lon);
mNMEAMode = NMEAMODE.TWO_DIMENSION;
//Console.WriteLine("Position {0}", mPosition.ToString());
}
/// <summary>
/// Parses a GPSD 'o' report.
/// Attempts to return a complete time/position/velocity report as a unit.
/// Any field for which data is not available being reported as ?.
/// If there is no fix, the response is simply "O=?", otherwise a tag and timestamp are always reported.
/// </summary>
/// <param name="sentence">GPSD 'o' report.</param>
/// <exception cref="System.Exception">Thrown if the sentence is not a GPSD report or sentence is not an 'O' report.</exception>
public void Parse(string sentence)
{
// break up the sentence into fields
Char[] splitChars = { ' ' };
string[] fields = sentence.Split(splitChars);
// validate the sentence
if (!fields[0].StartsWith("O="))
{
throw new Exception("Invalid sentence, not an 'O' report.");
}
// make sure there is a complete report
if (fields[0] == "O=?")
{
// need to invalidate all data
fields = new string[] { "O=?", "?", "?", "?", "?", "?", "?", "?", "?", "?", "?", "?", "?", "?", "?" }
}
;
if (fields.Length != 15)
{
throw new Exception("Invalid sentence, invalid field count.");
}
// looks good to go
mTag = fields[0].Substring(2);
// check that this is a fresh update
double newStamp = (fields[1] == "?")? Double.NaN : Double.Parse(fields[1]);
mInvalid = (newStamp == double.NaN);
mTimeStamp = new DateTime((long)newStamp);
mTimeError = (fields[2] == "?")? Double.NaN : Double.Parse(fields[2]);
mPosition.Reset((fields[3] == "?")? Double.NaN : Double.Parse(fields[3]), (fields[4] == "?")? Double.NaN : Double.Parse(fields[4]));
mAltitude = (fields[5] == "?")? Double.NaN : Double.Parse(fields[5]);
mHorizontalErrorEstimate = (fields[6] == "?")? 0.0 : Double.Parse(fields[6]);
mVerticalErrorEstimate = (fields[7] == "?")? Double.NaN : Double.Parse(fields[7]);
mCourseOverGround = (fields[8] == "?")? Double.NaN : Double.Parse(fields[8]);
mSpeedOverGround = (fields[9] == "?")? Double.NaN : Double.Parse(fields[9]);
mClimbSink = (fields[10] == "?")? Double.NaN : Double.Parse(fields[10]);
mEstimatedErrorCourseOverGround = (fields[11] == "?")? Double.MaxValue : Double.Parse(fields[11]);
mEstimatedErrorSpeedOverGround = (fields[12] == "?")? Double.MaxValue : Double.Parse(fields[12]);
mEstimatedErrorClimbSink = (fields[13] == "?")? Double.MaxValue : Double.Parse(fields[13]);
mNMEAMode = (NMEAMODE)((fields[14] == "?")? 0 : Int32.Parse(fields[14]));
}
/// <summary>
/// Parses a raw NMEA RMC (recommended minimum data for gps) sentence.
/// This provides the least information for positions but is guarenteed to be generated by all GPS units.
/// </summary>
/// <remarks>
/// $GPRMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,ddmmyy,x.x,a*hh
/// 1 = UTC of position fix
/// 2 = Data status (Navigation receiver warning A = OK, V = warning)
/// 3 = Latitude of fix
/// 4 = N or S
/// 5 = Longitude of fix
/// 6 = E or W
/// 7 = Speed over ground in knots
/// 8 = Track made good in degrees True
/// 9 = UT date
/// 10 = Magnetic variation degrees (Easterly var. subtracts from true course)
/// 11 = E or W
/// 12 = Checksum
/// </remarks>
/// <param name="sentence">NMEA RMC Senetence.</param>
/// <returns>True if the sentence is successfully parsed.</returns>
public bool ParseRMC(string sentence)
{
bool success = true;
// The sentence should be a comma seperated list of values
// Some may be empty!
// Start by stripping the leading and trailing data.
Char[] splitChars = { ',' };
//string[] words = sentence.Substring(1, sentence.IndexOf('*')).Split(splitChars, StringSplitOptions.None);
string[] words = sentence.Split(splitChars, StringSplitOptions.None);
// save the sentence type
mTag = words[0];
// Do we have enough words to parse the fix status?
if (words.Length > 2 && words[2].Length != 0)
{
// Get the fix flag
//if (words[2].Equals("A", StringComparison.OrdinalIgnoreCase))
// mNMEAMode = NMEAMODE.TWO_DIMENSION;
//else
//{
// mNMEAMode = NMEAMODE.NO_FIX;
// return false;
//}
if (!words[2].Equals("A", StringComparison.OrdinalIgnoreCase))
{
mNMEAMode = NMEAMODE.NO_FIX;
return(false);
}
}
else
{
// The fix status is invalid
mNMEAMode = NMEAMODE.NO_MODE;
success = false;
}
// Do we have enough words to parse the UTC date/time?
if (words.Length > 9)
{
if (words[1].Length != 0 && words[9].Length != 0)
{
try
{
// time part
string utcTimeWord = words[1];
int utcHours = int.Parse(utcTimeWord.Substring(0, 2), NMEAGPSClient.NMEACultureInfo); // AA
int utcMinutes = int.Parse(utcTimeWord.Substring(2, 2), NMEAGPSClient.NMEACultureInfo); // BB
int utcSeconds = int.Parse(utcTimeWord.Substring(4, 2), NMEAGPSClient.NMEACultureInfo); // CC
int utcMilliseconds = 0;
if (utcTimeWord.Length > 6)
{
utcMilliseconds = Convert.ToInt32(float.Parse(utcTimeWord.Substring(6)) * 1000, NMEAGPSClient.NMEACultureInfo); // DDDD
}
// date part
string utcDateWord = words[9];
int utcDay = int.Parse(utcDateWord.Substring(0, 2), NMEAGPSClient.NMEACultureInfo);
int utcMonth = int.Parse(utcDateWord.Substring(2, 2), NMEAGPSClient.NMEACultureInfo);
int utcYear = int.Parse(utcDateWord.Substring(4, 2), NMEAGPSClient.NMEACultureInfo) + 2000;
// make the date/time
mTimeStamp = new DateTime(utcYear, utcMonth, utcDay, utcHours, utcMinutes, utcSeconds, utcMilliseconds, DateTimeKind.Utc);
//CNXLog.InfoFormat("ParseRMC DateTime {0} time word {1} date word {2}", mTimeStamp.ToString(), words[1], words[9]);
}
catch (Exception e)
{
// The UTC date/time is invalid
CNXLog.ErrorFormat("ParseRMC DateTime error {0} {1}", sentence, e);
mTimeStamp = DateTime.MaxValue;
success = false;
}
}
else
{
// The UTC date/time is invalid
CNXLog.ErrorFormat("ParseRMC DateTime sentence length error {0} {1}", sentence);
mTimeStamp = DateTime.MaxValue;
success = false;
}
}
else
{
// The UTC date/time is invalid
CNXLog.ErrorFormat("ParseRMC DateTime sentence length error {0} {1}", sentence);
mTimeStamp = DateTime.MaxValue;
success = false;
}
// Do we have enough data to parse the location?
if (words.Length > 6 && words[3].Length != 0 && words[4].Length != 0 && words[5].Length != 0 && words[6].Length != 0)
{
mPosition = ParseNMEAPosition(words[3], words[4], words[5], words[6]);
}
// Do we have enough info to process speed?
if (words.Length > 7 && words[7].Length != 0)
{
// The speed is the sixth word, expressed in knots
// Conversion, 1,852 Knot to meter
mSpeedOverGround = ParseVelocity(words[7]);
}
else
{
mSpeedOverGround = double.MinValue;
}
// do we have enough info to process the bearing?
if (words.Length > 8 && words[8].Length != 0)
{
// The bearing is the seventh word
if (!double.TryParse(words[8], out mCourseOverGround))
{
mCourseOverGround = double.NaN;
}
}
else
{
mCourseOverGround = double.NaN;
}
return(success);
}