private void SubscribeContextEventHandlers(FlightContext context)
{
// Subscribe to the events so we can propagate 'em via the factory
context.OnTakeoff += (sender, args) => OnTakeoff?.Invoke(sender, args);
context.OnLaunchCompleted += (sender, args) => OnLaunchCompleted?.Invoke(sender, args);
context.OnLanding += (sender, args) => OnLanding?.Invoke(sender, args);
context.OnRadarContact += (sender, args) => OnRadarContact?.Invoke(sender, args);
context.OnCompletedWithErrors += (sender, args) => OnCompletedWithErrors?.Invoke(sender, args);
}
internal static void Initialize(this FlightContext context)
{
context.LatestTimeStamp = DateTime.MinValue;
context.Flight = new Flight
{
Aircraft = context.Options.AircraftId
};
context.StateMachine.Fire(FlightContext.Trigger.Next);
}
internal static AircraftRelation WhatAmI(this FlightContext context1, FlightContext context2)
{
var c2Position = context2.GetPositionAt(context1.CurrentPosition.TimeStamp);
if (c2Position == null &&
Math.Abs((context1.Flight.DepartureTime - context2.Flight.DepartureTime)?.TotalSeconds ?? 21) < 30)
{
return(AircraftRelation.Indeterministic);
}
else if (c2Position == null ||
context2.CurrentPosition == null ||
(context1.CurrentPosition.TimeStamp - context2.CurrentPosition.TimeStamp).TotalSeconds > 30 ||
context1.CurrentPosition.Location.DistanceTo(c2Position.Location) > 200)
{
// In this case we conclusively know there's nothing to be found
return(AircraftRelation.None);
}
var bearings = new List <double>();
for (var i = context1.Flight.PositionUpdates.Count - 1; i >= 0; i--)
{
var p1 = context1.Flight.PositionUpdates[i];
var p2 = context2.GetPositionAt(p1.TimeStamp);
// If this statement is true, the changes that our interpolation is right are getting more slim by the tick.
if (p1.TimeStamp < context2.Flight.PositionUpdates[0].TimeStamp)
{
break;
}
if (Math.Abs(p1.Speed - p2.Speed) > 20 ||
Math.Abs(p1.Altitude - p2.Altitude) > 100 ||
p1.Location.DistanceTo(p2.Location) > 200)
{
return(AircraftRelation.None);
}
var angle = (p1.Location.DegreeBearing(p2.Location) - p1.Heading + 360) % 360;
bearings.Add(angle);
}
var bearing = Geo.MeanAngle(bearings.ToArray());
return(90 < bearing && bearing < 270
? AircraftRelation.Towplane
: AircraftRelation.OnTow);
}
public IEnumerable <FlightContext> FindNearby(FlightContext context, double distance = 0.2)
{
if (context == null)
{
throw new ArgumentException($"{nameof(context)} should not be null");
}
var nearbyPositions = _map.Nearby(new PositionUpdate(null, DateTime.MinValue, context.CurrentPosition.Location.Y, context.CurrentPosition.Location.X), distance);
foreach (var position in nearbyPositions)
{
if (position.Aircraft != context.Options.AircraftId)
{
yield return(_flightContextDictionary[position.Aircraft]);
}
}
}
internal static IEnumerable <Encounter> TowEncounter(this FlightContext context)
{
var nearbyAircraft = context.Options.NearbyAircraftAccessor?.Invoke(
context.CurrentPosition.Location,
0.5)
.ToList();
if (nearbyAircraft == null)
{
yield break;
}
foreach (var aircraft in nearbyAircraft)
{
var iAm = context.WhatAmI(aircraft);
if (iAm == AircraftRelation.OnTow)
{
yield return(new Encounter
{
Aircraft = aircraft.Options.AircraftId,
Start = aircraft.Flight.DepartureTime,
Type = EncounterType.Tug
});
}
else if (iAm == AircraftRelation.Towplane)
{
yield return(new Encounter
{
Aircraft = aircraft.Options.AircraftId,
Start = aircraft.Flight.DepartureTime,
Type = EncounterType.Tow
});
}
else if (iAm == AircraftRelation.Indeterministic)
{
yield return(null);
}
}
}
internal static void TrackAerotow(this FlightContext context)
{
// ToDo: Think about the possibility of a paired landing.
if (context.Options.AircraftAccessor == null)
{
throw new Exception($"Unable to track tow without {nameof(FlightContextFactory)}");
}
var target = context.Flight.Encounters
.FirstOrDefault(q => q.Type == Models.EncounterType.Tow ||
q.Type == Models.EncounterType.Tug);
if (target == null)
{
// Note of caution; this situation should ideally never happen. If it does it would be a design flaw in the state machine?
context.StateMachine.Fire(FlightContext.Trigger.LaunchCompleted);
return;
}
var otherContext = context.Options.AircraftAccessor(target.Aircraft);
var iAm = context.WhatAmI(otherContext);
if (iAm == null)
{
return; // (I'm nothing. Try again next time)
}
if (iAm == Internal.Geo.AircraftRelation.None ||
(target.Type == Models.EncounterType.Tow && iAm != Internal.Geo.AircraftRelation.Towplane) ||
(target.Type == Models.EncounterType.Tug && iAm != Internal.Geo.AircraftRelation.OnTow))
{
target.End = context.CurrentPosition.TimeStamp;
context.StateMachine.Fire(FlightContext.Trigger.LaunchCompleted);
context.InvokeOnLaunchCompletedEvent();
return;
}
}
internal static void Stationary(this FlightContext context)
{
if (context.CurrentPosition == null)
{
return;
}
if (context.CurrentPosition.Speed > 30)
{
double groundElevation = 0;
if (context.Options.NearbyRunwayAccessor != null)
{
groundElevation = context.Options.NearbyRunwayAccessor(
context.CurrentPosition.Location,
Constants.RunwayQueryRadius)?
.OrderBy(q => q.Sides
.Min(w => Geo.DistanceTo(w, context.CurrentPosition.Location))
).FirstOrDefault()
?.Sides
.Average(q => q.Z)
?? 0;
}
// Walk back to when the speed was 0
var start = context.Flight.PositionUpdates
.Where(q => (q.Speed == 0 || double.IsNaN(q.Speed)) &&
(context.CurrentPosition.TimeStamp - q.TimeStamp).TotalSeconds < 30)
.OrderByDescending(q => q.TimeStamp)
.FirstOrDefault();
if (start == null && context.CurrentPosition.Altitude > (groundElevation + Constants.ArrivalHeight))
{
// The flight was already in progress, or we could not find the starting point (trees in line of sight?)
// Create an estimation about the departure time. Unless contact happens high in the sky
context.Flight.DepartureInfoFound = false;
context.InvokeOnRadarContactEvent();
context.StateMachine.Fire(FlightContext.Trigger.TrackMovements);
return;
}
else if (start == null && context.CurrentPosition.Altitude <= (groundElevation + Constants.ArrivalHeight))
{
// ToDo: Try to estimate the departure time
context.Flight.DepartureTime = context.CurrentPosition.TimeStamp;
context.Flight.DepartureLocation = context.CurrentPosition.Location;
context.Flight.PositionUpdates
.Where(q => q.TimeStamp < context.Flight.DepartureTime.Value)
.ToList()
.ForEach(q => context.Flight.PositionUpdates.Remove(q));
context.Flight.DepartureInfoFound = false;
}
else if (start != null)
{
context.Flight.DepartureTime = start.TimeStamp;
context.Flight.DepartureLocation = context.CurrentPosition.Location;
// Remove points not related to this flight
context.Flight.PositionUpdates
.Where(q => q.TimeStamp < context.Flight.DepartureTime.Value)
.ToList()
.ForEach(q => context.Flight.PositionUpdates.Remove(q));
context.Flight.DepartureInfoFound = false;
}
context.Flight.DepartureHeading = (short)context.CurrentPosition.Heading;
context.InvokeOnTakeoffEvent();
context.StateMachine.Fire(FlightContext.Trigger.Depart);
}
}
internal static void Departing(this FlightContext context)
{
/*
* First check plausible scenarios. The easiest to track is an aerotow.
*
* If not, wait until the launch is completed.
*/
if (context.Flight.LaunchMethod == LaunchMethods.None)
{
var departure = context.Flight.PositionUpdates
.Where(q => q.Heading != 0 && !double.IsNaN(q.Heading))
.OrderBy(q => q.TimeStamp)
.Take(5)
.ToList();
if (departure.Count > 4)
{
context.Flight.DepartureHeading = Convert.ToInt16(departure.Average(q => q.Heading));
if (context.Flight.DepartureHeading == 0)
{
context.Flight.DepartureHeading = 360;
}
// Only start method recognition after the heading has been determined
context.Flight.LaunchMethod = LaunchMethods.Unknown | LaunchMethods.Aerotow | LaunchMethods.Winch | LaunchMethods.Self;
}
else
{
return;
}
}
if (context.Flight.DepartureTime != null &&
(context.CurrentPosition.TimeStamp - (context.Flight.PositionUpdates.FirstOrDefault(q => q.Speed > 30)?.TimeStamp ?? context.CurrentPosition.TimeStamp)).TotalSeconds < 10)
{
return;
}
// We can safely try to extract the correct path
if (context.Flight.LaunchMethod.HasFlag(LaunchMethods.Unknown | LaunchMethods.Aerotow))
{
var encounters = context.TowEncounter().ToList();
if (encounters.Count(q => q?.Type == EncounterType.Tug || q?.Type == EncounterType.Tow) > 1)
{
return;
}
var encounter = encounters.SingleOrDefault(q => q?.Type == EncounterType.Tug || q?.Type == EncounterType.Tow);
if (encounter != null)
{
context.Flight.LaunchMethod = LaunchMethods.Aerotow
| (encounter.Type == EncounterType.Tug
? LaunchMethods.OnTow
: LaunchMethods.TowPlane
);
context.Flight.Encounters.Add(encounter);
context.StateMachine.Fire(FlightContext.Trigger.TrackAerotow);
return;
}
else if (encounters.Any(q => q == null))
{
return;
}
context.Flight.LaunchMethod &= ~LaunchMethods.Aerotow;
}
if (context.Flight.LaunchMethod.HasFlag(LaunchMethods.Unknown))
{
var x = new DenseVector(context.Flight.PositionUpdates.Select(w => (w.TimeStamp - context.Flight.DepartureTime.Value).TotalSeconds).ToArray());
var y = new DenseVector(context.Flight.PositionUpdates.Select(w => w.Altitude).ToArray());
var interpolation = CubicSpline.InterpolateNatural(x, y);
var r = new List <double>();
var r2 = new List <double>();
for (var i = 0; i < (context.CurrentPosition.TimeStamp - context.Flight.DepartureTime.Value).TotalSeconds; i++)
{
r.Add(interpolation.Differentiate(i));
r2.Add(interpolation.Differentiate2(i));
}
// When the initial climb has completed
if (interpolation.Differentiate((context.CurrentPosition.TimeStamp - context.Flight.DepartureTime.Value).TotalSeconds) < 0)
{
// Skip the first element because heading is 0 when in rest
var averageHeading = context.Flight.PositionUpdates.Skip(1).Average(q => q.Heading);
// ToDo: Add check to see whether there is another aircraft nearby
if (context.Flight.PositionUpdates
.Skip(1)
.Where(q => interpolation.Differentiate((context.CurrentPosition.TimeStamp - context.Flight.DepartureTime.Value).TotalSeconds) > 0)
.Select(q => Geo.GetHeadingError(averageHeading, q.Heading))
.Any(q => q > 20) ||
Geo.DistanceTo(
context.Flight.PositionUpdates.First().Location,
context.CurrentPosition.Location) > 3000)
{
context.Flight.LaunchMethod = LaunchMethods.Self;
}
else
{
context.Flight.LaunchMethod = LaunchMethods.Winch;
}
context.Flight.LaunchFinished = context.CurrentPosition.TimeStamp;
context.InvokeOnLaunchCompletedEvent();
context.StateMachine.Fire(FlightContext.Trigger.LaunchCompleted);
}
}
}
internal static AircraftRelation TrackTow(this FlightContext context1, FlightContext context2)
{
if (context1.Flight.PositionUpdates.Count < 5 || context2.Flight.PositionUpdates.Count < 5)
{
return(AircraftRelation.None);
}
var interpolation = Interpolation.Interpolate(
context1.Flight.PositionUpdates,
context2.Flight.PositionUpdates,
q => q.TimeStamp.Ticks,
(object1, object2, time) =>
{
var dX = object2.Location.X - object1.Location.X;
var dY = object2.Location.Y - object1.Location.Y;
var dT = (object2.TimeStamp - object1.TimeStamp).Ticks;
if (dT == 0)
{
return(null);
}
double factor = (time - object1.TimeStamp.Ticks) / (double)dT;
return(new PositionUpdate(
"",
new DateTime((long)(object1.TimeStamp.Ticks + dT * factor)),
object1.Location.Y + factor * dY,
object1.Location.X + factor * dX));
});
/*
* We only care about the following two characteristics;
* 1. In relation to the glider, the towplane is always in front -90 to +90 bearing
* 2. The aircraft should be no more than 200 meters apart for any interpolated point
*
* As soon as any of these is false, the tow has ended.
*/
bool?isTowed = null;
foreach (var dataPoint in interpolation)
{
if (dataPoint.T1.Location.DistanceTo(dataPoint.T2.Location) > 200)
{
break;
}
// Determine the position irt to the other aircraft
var bearing = dataPoint.T1.Location.DegreeBearing(dataPoint.T2.Location);
if (90 < bearing && bearing < 270)
{
// We're being towed
if (isTowed == null)
{
isTowed = true;
}
else if (isTowed == false)
{
return(AircraftRelation.None);
}
}
else
{
// We're towing
if (isTowed == null)
{
isTowed = false;
}
else if (isTowed == true)
{
return(AircraftRelation.None);
}
}
}
if (isTowed == null)
{
return(AircraftRelation.None);
}
return(isTowed.Value
? AircraftRelation.OnTow
: AircraftRelation.Towplane);
}
/// <summary> /// The attach method can be used to add an already existing context instance to this factory. /// This method will overwrite any FlightContext instance with the same aircraft identifier already /// tracked by this FlightContextFactory. /// </summary> /// <param name="context"></param> public void Attach(FlightContext context) => Attach(context?.Flight);
internal static void Arriving(this FlightContext context)
{
/*
* - Create an estimate for the arrival time
* - When data shows a landing, use that data
* - When no data is received anymore, use the estimation
*/
double groundElevation = 0;
if (context.Options.NearbyRunwayAccessor != null)
{
groundElevation = context.Options.NearbyRunwayAccessor(
context.CurrentPosition.Location,
Constants.RunwayQueryRadius)?
.OrderBy(q => q.Sides
.Min(w => Geo.DistanceTo(w, context.CurrentPosition.Location))
).FirstOrDefault()
?.Sides
.Average(q => q.Z)
?? 0;
}
if (context.CurrentPosition.Altitude > (groundElevation + Constants.ArrivalHeight))
{
context.Flight.ArrivalTime = null;
context.Flight.ArrivalInfoFound = null;
context.Flight.ArrivalHeading = 0;
context.StateMachine.Fire(FlightContext.Trigger.LandingAborted);
return;
}
var arrival = context.Flight.PositionUpdates
.Where(q => q.Heading != 0 && !double.IsNaN(q.Heading))
.OrderByDescending(q => q.TimeStamp)
.Take(5)
.ToList();
if (!arrival.Any())
{
return;
}
if (context.CurrentPosition.Speed == 0)
{
/*
* If a flight has been in progress, end the flight.
*
* When the aircraft has been registered mid flight the departure
* location is unknown, and so is the time. Therefore look at the
* flag which is set to indicate whether the departure location has
* been found.
*
* ToDo: Also check the vertical speed as it might be an indication
* that the flight is still in progress! (Aerobatic stuff and so)
*/
context.Flight.ArrivalTime = context.CurrentPosition.TimeStamp;
context.Flight.ArrivalInfoFound = true;
context.Flight.ArrivalHeading = Convert.ToInt16(arrival.Average(q => q.Heading));
context.Flight.ArrivalLocation = arrival.First().Location;
if (context.Flight.ArrivalHeading == 0)
{
context.Flight.ArrivalHeading = 360;
}
context.InvokeOnLandingEvent();
context.StateMachine.Fire(FlightContext.Trigger.Arrived);
}
else if (!(context.Flight.ArrivalInfoFound ?? true) &&
context.CurrentPosition.TimeStamp > context.Flight.ArrivalTime.Value.AddSeconds(Constants.ArrivalTimeout))
{
// Our theory needs to be finalized
context.InvokeOnLandingEvent();
context.StateMachine.Fire(FlightContext.Trigger.Arrived);
}
else
{
var previousPoint = context.Flight.PositionUpdates.LastOrDefault();
if (previousPoint == null)
{
return;
}
// Take the average climbrate over the last few points
var climbrates = new List <double>();
var speeds = new List <double>();
for (var i = context.Flight.PositionUpdates.Count - 1; i > Math.Max(context.Flight.PositionUpdates.Count - 15, 0); i--)
{
var p1 = context.Flight.PositionUpdates[i];
var p2 = context.Flight.PositionUpdates[i - 1];
var deltaAltitude = p1.Altitude - p2.Altitude;
var deltaTime = p1.TimeStamp - p2.TimeStamp;
speeds.Add(p1.Speed);
climbrates.Add(deltaAltitude / deltaTime.TotalSeconds);
}
if (!climbrates.Any())
{
context.Flight.ArrivalTime = null;
context.Flight.ArrivalInfoFound = null;
context.Flight.ArrivalHeading = 0;
context.Flight.ArrivalLocation = null;
return;
}
var average = climbrates.Average();
double ETUA = context.CurrentPosition.Altitude / -average;
if (double.IsInfinity(ETUA) || ETUA > (60 * 10) || ETUA < 0)
{
context.Flight.ArrivalTime = null;
context.Flight.ArrivalInfoFound = null;
context.Flight.ArrivalHeading = 0;
context.Flight.ArrivalLocation = null;
return;
}
var averageHeading = arrival.Average(q => q.Heading);
context.Flight.ArrivalTime = context.CurrentPosition.TimeStamp.AddSeconds(ETUA);
context.Flight.ArrivalInfoFound = false;
context.Flight.ArrivalHeading = Convert.ToInt16(averageHeading);
context.Flight.ArrivalLocation = context.CurrentPosition.Location.HaversineExtrapolation(
averageHeading,
speeds.Average() * 0.514444444 * ETUA); // Knots to m/s times the estimated time until arrival
}
}