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Merge branch 'main' of https://github.com/dotMorten/NmeaParser into main
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Morten Nielsen
commit
804ff218a9
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@ -54,137 +54,100 @@ namespace NmeaParser.ArcGIS
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```
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### Combining multiple NMEA messages into a single location event
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NMEA often happens in a burst of messages, which could be combined to one larger location object with more information available.
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By relying on the time stamp in most of the messages, we can combine them all to get better metadata about the location.
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NMEA often happens in a burst of messages, which could be combined to one larger location object with more information available, as well as containing information from multiple different satellite systems.
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By using the `GnssMonitor` class that aggregates these messages, we can create a much more robust location provider:
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```
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using System;
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using System.Linq;
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using System.Threading.Tasks;
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using Esri.ArcGISRuntime.Geometry;
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using Esri.ArcGISRuntime.Location;
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using NmeaParser;
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using NmeaParser.Messages;
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using NmeaParser.Gnss;
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namespace NmeaParser.ArcGIS
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{
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public class NmeaLocationProvider : LocationDataSource
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public class NmeaLocationDataSource : Esri.ArcGISRuntime.Location.LocationDataSource
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{
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private readonly NmeaParser.NmeaDevice device;
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private Gga lastGga;
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private Rmc lastRmc;
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private Gsa lastGsa;
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private Gst lastGst;
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private static SpatialReference wgs84_ellipsoidHeight = SpatialReference.Create(4326, 115700);
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private readonly GnssMonitor m_gnssMonitor;
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private readonly bool m_startStopDevice;
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private double lastCourse = 0; // Course can fallback to NaN, but ArcGIS Datasource don't allow NaN course, so we cache last known as a fallback
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public NmeaLocationProvider(NmeaParser.NmeaDevice device)
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/// <summary>
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/// Initializes a new instance of the <see cref="NmeaLocationDataSource"/> class.
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/// </summary>
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/// <param name="device">The NMEA device to monitor</param>
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/// <param name="startStopDevice">Whether starting this datasource also controls the underlying NMEA device</param>
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public NmeaLocationDataSource(NmeaParser.NmeaDevice device, bool startStopDevice = true) : this(new GnssMonitor(device), startStopDevice)
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{
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this.device = device;
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device.MessageReceived += NmeaMessageReceived;
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}
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private void NmeaMessageReceived(object sender, NmeaMessageReceivedEventArgs e)
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/// <summary>
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/// Initializes a new instance of the <see cref="NmeaLocationDataSource"/> class.
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/// </summary>
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/// <param name="monitor">The NMEA device to monitor</param>
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/// <param name="startStopDevice">Whether starting this datasource also controls the underlying NMEA device</param>
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public NmeaLocationDataSource(NmeaParser.Gnss.GnssMonitor monitor, bool startStopDevice = true)
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{
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var message = e.Message;
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bool newFix = false;
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if (message is Rmc rmc && rmc.Active)
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{
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lastRmc = rmc;
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newFix = true;
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}
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else if (message is Gga gga)
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{
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lastGga = gga;
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newFix = true;
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}
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else if (message is Gst gst)
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{
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lastGst = gst;
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newFix = true;
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}
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else if (message is Gsa gsa)
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{
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lastGsa = gsa;
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}
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if (monitor == null)
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throw new ArgumentNullException(nameof(monitor));
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this.m_gnssMonitor = monitor;
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m_startStopDevice = startStopDevice;
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}
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protected async override Task OnStartAsync()
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{
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m_gnssMonitor.LocationChanged += OnLocationChanged;
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m_gnssMonitor.LocationLost += OnLocationChanged;
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if (m_startStopDevice && !this.m_gnssMonitor.Device.IsOpen)
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await this.m_gnssMonitor.Device.OpenAsync();
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if (m_gnssMonitor.IsFixValid)
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OnLocationChanged(this, EventArgs.Empty);
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}
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protected override Task OnStopAsync()
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{
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m_gnssMonitor.LocationChanged -= OnLocationChanged;
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m_gnssMonitor.LocationLost -= OnLocationChanged;
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if(m_startStopDevice)
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return m_gnssMonitor.Device.CloseAsync();
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else
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{
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return;
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}
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// We require the timestamps to match to raise them together. Gsa doesn't have a time stamp so just using latest for that
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TimeSpan? timeOfFixMax = MaxTime(lastRmc?.FixTime.TimeOfDay, lastGga?.FixTime, lastGst?.FixTime);
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TimeSpan? timeOfFixMin = MinTime(lastRmc?.FixTime.TimeOfDay, lastGga?.FixTime, lastGst?.FixTime);
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if (newFix && timeOfFixMax == timeOfFixMin)
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{
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var location = NmeaLocation.Create(timeOfFixMax.Value, lastRmc, lastGga, lastGsa, lastGst);
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if (location != null)
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base.UpdateLocation(location);
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}
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return Task.CompletedTask;
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}
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private static TimeSpan? MaxTime(params TimeSpan?[] timeSpans) => timeSpans.Where(t => t != null).Max();
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private static TimeSpan? MinTime(params TimeSpan?[] timeSpans) => timeSpans.Where(t => t != null).Min();
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protected override Task OnStartAsync() => device.OpenAsync();
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protected override Task OnStopAsync() => device.CloseAsync();
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}
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private Esri.ArcGISRuntime.Location.Location currentLocation;
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/// <summary>
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/// Custom location class with the additional NMEA information associated with it
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/// </summary>
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public class NmeaLocation : Location
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{
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private NmeaLocation(DateTimeOffset? timestamp, MapPoint position, double horizontalAccuracy, double verticalAccuracy, double velocity, double course, bool isLastKnown)
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: base(timestamp, position, horizontalAccuracy, verticalAccuracy, velocity, course, isLastKnown)
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private void OnLocationChanged(object sender, EventArgs e)
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{
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if (double.IsNaN(m_gnssMonitor.Longitude) || double.IsNaN(m_gnssMonitor.Latitude)) return;
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if (!double.IsNaN(m_gnssMonitor.Course))
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lastCourse = m_gnssMonitor.Course;
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DateTimeOffset? timestamp = null;
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if(m_gnssMonitor.FixTime.HasValue)
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timestamp = new DateTimeOffset(DateTime.UtcNow.Date.Add(m_gnssMonitor.FixTime.Value));
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var location = new Esri.ArcGISRuntime.Location.Location(
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timestamp: timestamp,
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position: !double.IsNaN(m_gnssMonitor.Altitude) ? new MapPoint(m_gnssMonitor.Longitude, m_gnssMonitor.Latitude, m_gnssMonitor.Altitude, wgs84_ellipsoidHeight) : new MapPoint(m_gnssMonitor.Longitude, m_gnssMonitor.Latitude, SpatialReferences.Wgs84),
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horizontalAccuracy: m_gnssMonitor.HorizontalError,
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verticalAccuracy: m_gnssMonitor.VerticalError,
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velocity: double.IsNaN(m_gnssMonitor.Speed) ? 0 : m_gnssMonitor.Speed * 0.51444444,
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course: lastCourse,
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!m_gnssMonitor.IsFixValid);
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// Avoid raising additional location events if nothing changed
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if (currentLocation == null ||
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currentLocation.Position.X != location.Position.X ||
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currentLocation.Position.Y != location.Position.Y ||
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currentLocation.Position.Z != location.Position.Z ||
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currentLocation.Course != location.Course ||
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currentLocation.Velocity != location.Velocity ||
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currentLocation.HorizontalAccuracy != location.HorizontalAccuracy ||
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currentLocation.VerticalAccuracy != location.VerticalAccuracy ||
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currentLocation.IsLastKnown != location.IsLastKnown ||
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timestamp != location.Timestamp)
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{
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currentLocation = location;
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UpdateLocation(currentLocation);
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}
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}
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public static NmeaLocation Create(TimeSpan timeOfFix, Rmc rmc, Gga gga, Gsa gsa, Gst gst)
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{
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MapPoint position = null;
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double horizontalAccuracy = double.NaN;
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double verticalAccuracy = double.NaN;
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double velocity = 0;
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double course = 0;
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// Prefer GGA over RMC for location
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if (gga != null && gga.FixTime == timeOfFix)
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{
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if (double.IsNaN(gga.Altitude))
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position = new MapPoint(gga.Longitude, gga.Latitude, SpatialReferences.Wgs84);
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else
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{
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// Vertical id 115700 == ellipsoid reference system. Gga is geoid, but we subtract GeoidalSeparation to simplify
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// vertical transformations from the simpler/better known ellipsoidal model
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position = new MapPoint(gga.Longitude, gga.Latitude, gga.Altitude + gga.GeoidalSeparation, SpatialReference.Create(4326, 115700));
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}
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}
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if (rmc != null && rmc.FixTime.TimeOfDay == timeOfFix)
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{
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if (position == null)
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{
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position = new MapPoint(rmc.Longitude, rmc.Latitude, SpatialReferences.Wgs84);
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}
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velocity = double.IsNaN(rmc.Speed) ? 0 : rmc.Speed;
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course = double.IsNaN(rmc.Course) ? 0 : rmc.Course;
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}
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if (gst != null && gst.FixTime == timeOfFix)
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{
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verticalAccuracy = gst.SigmaHeightError;
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horizontalAccuracy = gst.SemiMajorError;
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}
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if (position == null)
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return null;
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var location = new NmeaLocation(DateTimeOffset.UtcNow.Date.Add(timeOfFix), position, horizontalAccuracy, verticalAccuracy, velocity, course, false);
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location.Rmc = rmc;
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location.Gga = gga;
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location.Gsa = gsa;
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location.Gst = gst?.FixTime == timeOfFix ? gst : null;
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return location;
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}
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public Rmc Rmc { get; private set; }
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public Gga Gga { get; private set; }
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public Gsa Gsa { get; private set; }
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public Gst Gst { get; private set; }
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public int NumberOfSatellites => Gga?.NumberOfSatellites ?? -1;
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public double Hdop => Gsa?.Hdop ?? Gga?.Hdop ?? double.NaN;
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public double Pdop => Gsa?.Pdop ?? double.NaN;
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public double Vdop => Gsa?.Vdop ?? double.NaN;
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}
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}
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```
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