/// <summary>
/// Reads the UTC date and time from the next available sentence.
/// </summary>
/// <returns></returns>
public DateTime ReadUtcDateTime()
{
// Does it support the value we want?
IUtcDateTimeSentence sentence = ReadTypedSentence() as IUtcDateTimeSentence;
// If not, start over (recursive)
while (sentence == null)
{
sentence = ReadTypedSentence() as IUtcDateTimeSentence;
}
// Return the location
return(sentence.UtcDateTime);
}
public void Parse(NmeaSentence sentence)
{
/* NMEA data is parsed in a specific order to maximize data quality and also to reduce latency
* problems. The date/time is processed first to minimize latency. Then, dilution of precision
* values are processed. Finally, if precision is good enough to work with, remaining values are
* processed.
*/
// Is this a fix method message?
IFixMethodSentence fixMethodSentence = sentence as IFixMethodSentence;
if (fixMethodSentence != null)
{
SetFixMethod(fixMethodSentence.FixMethod);
}
// Is this a fix quality message?
IFixQualitySentence fixQualitySentence = sentence as IFixQualitySentence;
if (fixQualitySentence != null)
{
SetFixQuality(fixQualitySentence.FixQuality);
}
#region Process common GPS information
// If a fix is required, don't process time
if (!IsFixRequired || (IsFixRequired && IsFixed))
{
// Does this sentence support the UTC date and time?
IUtcDateTimeSentence dateTimeSentence = sentence as IUtcDateTimeSentence;
if (dateTimeSentence != null)
{
SetDateTimes(dateTimeSentence.UtcDateTime);
}
/* Some NMEA sentences provide UTC time information, but no date! To make this work,
* we must combine the time report with the current UTC date.
*/
IUtcTimeSentence timeSentence = sentence as IUtcTimeSentence;
if (timeSentence != null && !timeSentence.UtcTime.Equals(TimeSpan.MinValue) && !timeSentence.UtcTime.Equals(TimeSpan.Zero))
{
SetDateTimes(new DateTime(DateTime.UtcNow.Year, DateTime.UtcNow.Month, DateTime.UtcNow.Day,
timeSentence.UtcTime.Hours, timeSentence.UtcTime.Minutes, timeSentence.UtcTime.Seconds, timeSentence.UtcTime.Milliseconds,
DateTimeKind.Utc));
}
}
// Does this sentence support horizontal DOP?
IHorizontalDilutionOfPrecisionSentence hdopSentence = sentence as IHorizontalDilutionOfPrecisionSentence;
if (hdopSentence != null)
{
SetHorizontalDilutionOfPrecision(hdopSentence.HorizontalDilutionOfPrecision);
}
// Does the sentence support vertical DOP?
IVerticalDilutionOfPrecisionSentence vdopSentence = sentence as IVerticalDilutionOfPrecisionSentence;
if (vdopSentence != null)
{
SetVerticalDilutionOfPrecision(vdopSentence.VerticalDilutionOfPrecision);
}
// Does the sentence support mean DOP?
IPositionDilutionOfPrecisionSentence mdopSentence = sentence as IPositionDilutionOfPrecisionSentence;
if (mdopSentence != null)
{
SetMeanDilutionOfPrecision(mdopSentence.PositionDilutionOfPrecision);
}
#endregion
// If a fix is required, don't process time
if (!IsFixRequired || (IsFixRequired && IsFixed))
{
// Is precision good enough to work with?
if (this.HorizontalDilutionOfPrecision.Value <= this.MaximumHorizontalDilutionOfPrecision.Value)
{
#region Process real-time positional data
// Does this sentence support lat/long info?
IPositionSentence positionSentence = sentence as IPositionSentence;
if (positionSentence != null)
{
SetPosition(positionSentence.Position);
}
// Does this sentence support bearing?
IBearingSentence bearingSentence = sentence as IBearingSentence;
if (bearingSentence != null)
{
SetBearing(bearingSentence.Bearing);
}
// Does this sentence support speed?
ISpeedSentence speedSentence = sentence as ISpeedSentence;
if (speedSentence != null)
{
SetSpeed(speedSentence.Speed);
}
#endregion
}
// Is the vertical DOP low enough to be worth processing?
if (this.VerticalDilutionOfPrecision.Value <= this.MaximumVerticalDilutionOfPrecision.Value)
{
#region Process altitude data
// Does this sentence support altitude?
IAltitudeSentence altitudeSentence = sentence as IAltitudeSentence;
if (altitudeSentence != null)
{
SetAltitude(altitudeSentence.Altitude);
}
// Does this sentence support altitude?
IAltitudeAboveEllipsoidSentence altitudeAboveEllipsoidSentence = sentence as IAltitudeAboveEllipsoidSentence;
if (altitudeAboveEllipsoidSentence != null)
{
SetAltitude(altitudeAboveEllipsoidSentence.AltitudeAboveEllipsoid);
}
// Does this sentence support geoidal separation?
IGeoidalSeparationSentence geoidSeparationSentence = sentence as IGeoidalSeparationSentence;
if (geoidSeparationSentence != null)
{
SetGeoidalSeparation(geoidSeparationSentence.GeoidalSeparation);
}
#endregion
}
}
#region Lower-priority information
// Is this a fix mode sentence?
IFixModeSentence fixModeSentence = sentence as IFixModeSentence;
if (fixModeSentence != null)
{
SetFixMode(fixModeSentence.FixMode);
}
// Does this sentence have fix status?
IFixStatusSentence fixedSentence = sentence as IFixStatusSentence;
if (fixedSentence != null)
{
SetFixStatus(fixedSentence.FixStatus);
}
// Does this sentence support magnetic variation?
IMagneticVariationSentence magVarSentence = sentence as IMagneticVariationSentence;
if (magVarSentence != null)
{
SetMagneticVariation(magVarSentence.MagneticVariation);
}
// Process satellite data
ISatelliteCollectionSentence satelliteSentence = sentence as ISatelliteCollectionSentence;
if (satelliteSentence != null)
{
/* GPS.NET 2.0 performed thorough comparison of satellites in order to update
* an *existing* instance of Satellite objects. I think now that this was overkill.
* For performance and limited memory use, satellites are just overwritten.
*/
AppendSatellites(satelliteSentence.Satellites);
}
// Fixed satellite count
IFixedSatelliteCountSentence fixedCountSentence = sentence as IFixedSatelliteCountSentence;
if (fixedCountSentence != null)
{
SetFixedSatelliteCount(fixedCountSentence.FixedSatelliteCount);
}
// Process fixed satellites
IFixedSatellitesSentence fixedSatellitesSentence = sentence as IFixedSatellitesSentence;
if (fixedSatellitesSentence != null)
{
SetFixedSatellites(fixedSatellitesSentence.FixedSatellites);
}
#endregion
}
