/// <summary>
/// Processing a grounded flight
/// We can adjust its position and look for takeoffs
/// </summary>
private void ProcessGrounded(AdsbEvent currentEvent)
{
//Set the last auport first if it hasn been set yet
// This happens if we enter GROUNDED from Unknown
if (LastAirport == null && LastKnownPosition != null)
{
LastAirport = Airports.GetClosestAirport(LastKnownPosition);
}
// This is where we can process flights as they slow down. We can assume a reasonable distance here
// The goal is to get coser and closer with the airport until we hit taxi speed
// Inspired by A44D3F Delta - and the multitude of CLos Angeles area municipal airports
if (LastGroundedFlight != null)
{
if (currentEvent.Speed != null && currentEvent.Speed > REASONABLE_TAXI_SPEED)
{
Airport tempAirport = Airports.GetClosestAirport(LastKnownPosition);
if (tempAirport.Identifier != LastAirport.Identifier)
{
UpdateLastGroundedFlight(tempAirport);
}
}
}
//The goal here is to look for takeoffs
// This means we have a Reasonable grounding delay of 15 minutes before searching for takeoff speed
bool takeoffEligible = true;
if (LastGrounded != null)
{
// we will ignore events to let the plane land
TimeSpan landSpan = currentEvent.Timestamp.Subtract((DateTime)LastGrounded);
double landSeconds = landSpan.TotalSeconds;
if (landSeconds < REASONABLE_GROUNDING_DELAY)
{
takeoffEligible = false;
}
}
if ((currentEvent.Speed) != null && takeoffEligible)
{
LastDeviceSpeed = currentEvent.Speed;
LastDeviceSpeedTime = currentEvent.Timestamp;
// We have hit takeoff speed, change status
if (currentEvent.Speed > AirplaneProcessed.Model.TakeoffSpeed)
{
// We are taking off
//Console.WriteLine("Taking off at " + currentEvent.Timestamp);
CurrentStatus = AirplaneStatus.FLYING;
LastTakeoff = currentEvent.Timestamp;
}
}
}
private static FlightCollection CalculateFlights(AirportCollection airports, AdsbEventCollection events)
{
// Organize all ADS-B events by aircraft ID
FlightCollection flights = new FlightCollection();
Dictionary <string, List <AdsbEvent> > eventsByID = new Dictionary <string, List <AdsbEvent> >();
foreach (AdsbEvent adsbEvent in events.Events)
{
if (!eventsByID.ContainsKey(adsbEvent.Identifier))
{
eventsByID.Add(adsbEvent.Identifier, new List <AdsbEvent>());
eventsByID[adsbEvent.Identifier].Add(adsbEvent);
}
else
{
// Remove events that are soon after the previous one to improve performance
int eventCount = eventsByID[adsbEvent.Identifier].Count;
AdsbEvent lastEvent = eventsByID[adsbEvent.Identifier][eventCount - 1];
TimeSpan timeDiff = adsbEvent.Timestamp - lastEvent.Timestamp;
if (timeDiff.TotalSeconds >= TimeThreshold)
{
eventsByID[adsbEvent.Identifier].Add(adsbEvent);
}
}
}
// For each aircraft identifier, step through the logged events in sequence to identify flights
foreach (string identifier in eventsByID.Keys)
{
List <AdsbEvent> eventLog = eventsByID[identifier];
FlightStatus flightStatus = FlightStatus.Unknown;
Airport lastAirport = new Airport();
DateTime lastGroundTime = DateTime.MinValue;
foreach (AdsbEvent adsbEvent in eventLog)
{
// Find closest airport to the logged coordinates, as long as the event has coordinate values
GeoCoordinate eventLoc = new GeoCoordinate(adsbEvent.Latitude ?? double.NaN, adsbEvent.Longitude ?? double.NaN);
if (eventLoc.HasLocation())
{
Airport closestAirport = airports.GetClosestAirport(eventLoc);
GeoCoordinate airportLoc = new GeoCoordinate(closestAirport.Latitude, closestAirport.Longitude);
double airportDistance = eventLoc.GetDistanceTo(airportLoc);
double altitudeDiff = adsbEvent.Altitude.HasValue ? Math.Abs(adsbEvent.Altitude.Value - closestAirport.Elevation) : 0f;
double speed = adsbEvent.Speed ?? 0f;
// If the event was logged close to an airport, assume the aircraft has landed at that airport
if (airportDistance <= DistanceThreshold && altitudeDiff <= AltitudeThreshold && speed <= SpeedThreshold)
{
// If this is not the first event (status unknown) and the new closest airport is different, create a new completed flight record
if (flightStatus != FlightStatus.Unknown && closestAirport.Identifier != lastAirport.Identifier)
{
flights.Flights.Add(new Flight
{
AircraftIdentifier = identifier,
DepartureTime = lastGroundTime,
DepartureAirport = lastAirport.Identifier,
ArrivalTime = adsbEvent.Timestamp,
ArrivalAirport = closestAirport.Identifier
});
}
// In any case, update the status for the new airport
flightStatus = FlightStatus.Ground;
lastAirport = closestAirport;
lastGroundTime = adsbEvent.Timestamp;
}
// If the aircraft is not close to an airport and was not previously flying, set the status to airborne
else if ((airportDistance > DistanceThreshold || altitudeDiff > AltitudeThreshold) && flightStatus != FlightStatus.Air)
{
flightStatus = FlightStatus.Air;
}
// Otherwise, assume no status change
}
}
// If all events have been read and the aircraft was last known to be flying, record a final flight with no arrival
if (flightStatus == FlightStatus.Air)
{
flights.Flights.Add(new Flight
{
AircraftIdentifier = identifier,
DepartureTime = lastGroundTime,
DepartureAirport = lastAirport.Identifier,
ArrivalTime = DateTime.MaxValue,
ArrivalAirport = null
});
}
}
return(flights);
}
private static void Execute()
{
// Load the airports
AirportCollection airports = AirportCollection.LoadFromFile(AirportsFilePath);
var fileLines = System.IO.File.ReadAllLines(AdsbEventsFilePath);
Dictionary <string, List <AdsbEvent> > airplanes = new Dictionary <string, List <AdsbEvent> >();
foreach (var line in fileLines)
{
string airplaneId = Events.AdsbEvent.FromJson(line).Identifier;
if (airplanes.ContainsKey(airplaneId))
{
airplanes[airplaneId].Add(Events.AdsbEvent.FromJson(line));
}
else
{
List <AdsbEvent> tmpEventList = new List <AdsbEvent>()
{
Events.AdsbEvent.FromJson(line)
};
airplanes.Add(Events.AdsbEvent.FromJson(line).Identifier, tmpEventList);
}
}
System.IO.StreamWriter outFile = new System.IO.StreamWriter(OutputFilePath);
foreach (var key in airplanes.Keys)
{
// debug output
// System.Console.WriteLine(key);
// setting defaults
DateTime prevTime = DateTime.Parse("1/01/2020 12:00:00 AM");
GeoCoordinate prevAirportLocation = null;
Airport prevAirport = null;
Flight flight = new Flight();
flight.AircraftIdentifier = key;
foreach (var adsbEventEntry in airplanes[key])
{
// create a geolocation based on airplane adsb event coords
string latLong = adsbEventEntry.Latitude.ToString() + "," + adsbEventEntry.Longitude.ToString();
GeoCoordinate airplaneLocation = GeoCoordinate.FromLatitudeAndLongitudeString(latLong);
// get closest airport based on current airplane location
Airport tempAirport = airports.GetClosestAirport(airplaneLocation);
// create airport geolocation
string airportLatLong = tempAirport.Latitude.ToString() + "," + tempAirport.Longitude.ToString();
GeoCoordinate airportLocation = GeoCoordinate.FromLatitudeAndLongitudeString(airportLatLong);
// In order for an event to be a landing/takeoff:
// 1. geolocation within 5 miles of an airport (Flight safety, no unregistered aircraft within 5 miles of an airport)
// 2. altitude diff within 500 feet (safety altitude)
// 3. take off and landing speed < 200 mph
// In order for an airport to have a takeoff for this airplane:
// 1. The timestamp reads must have a difference > 30 mins
// Airplane heading and speed is not always present in adsbevent data, which means we can't rely on it to determine landing vs takeoff
double tempDist = airplaneLocation.GetDistanceTo(airportLocation);
if (tempDist < 5)
{
if (adsbEventEntry.Altitude != null && (adsbEventEntry.Altitude - tempAirport.Elevation <= 500) && adsbEventEntry.Speed != null && adsbEventEntry.Speed <= 200)
{
//did some reasearch, it looks like it takes the crew around 30-60 mins to get the plane checked again for next flight
if (adsbEventEntry.Timestamp - prevTime > TimeSpan.Parse("00:30:00"))
{
// logic for arrivals and departures
if (prevAirportLocation != null && prevAirportLocation != airportLocation)
{
//only departure is added w/ previous timestamp
flight.DepartureTime = prevTime;
flight.DepartureAirport = prevAirport.Identifier;
}
else if (prevAirportLocation == airportLocation)
{
//arrival is added w/ previous timestamp
flight.ArrivalTime = prevTime;
flight.ArrivalAirport = prevAirport.Identifier;
}
}
prevAirportLocation = airportLocation;
prevTime = adsbEventEntry.Timestamp;
prevAirport = tempAirport;
}
}
//record flights if arrival time is populated
if (flight.ArrivalAirport != null)
{
outFile.WriteLine(flight.ToString());
flight = new Flight();
flight.AircraftIdentifier = key;
}
}
}
outFile.Close();
}
