149 lines
4.6 KiB
Python
149 lines
4.6 KiB
Python
#!/usr/bin/env python
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from aman.com.Weather import Weather
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import math
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import scipy.interpolate
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class WeatherModel:
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def __init__(self, gaforId, weather : Weather):
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self.Gafor = gaforId
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self.Weather = weather
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self.WindDirectionModel = None
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self.WindSpeedModel = None
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self.LastWeatherUpdate = None
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self.MinimumAltitude = 1000000
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self.MaximumAltitude = -1
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# create the density interpolation model
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# the density model is based on https://aerotoolbox.com/atmcalc/
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altitudes = [
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50000,
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45000,
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40000,
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38000,
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36000,
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34000,
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32000,
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30000,
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28000,
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26000,
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24000,
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22000,
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20000,
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18000,
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16000,
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15000,
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14000,
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13000,
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12000,
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11000,
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10000,
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9000,
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8000,
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7000,
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6000,
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5000,
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4000,
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3000,
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2000,
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1000,
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0
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]
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densities = [
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0.18648,
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0.23714,
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0.24617,
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0.33199,
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0.36518,
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0.39444,
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0.42546,
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0.45831,
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0.402506,
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0.432497,
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0.464169,
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0.60954,
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0.65269,
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0.69815,
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0.74598,
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0.77082,
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0.79628,
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0.82238,
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0.84914,
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0.87655,
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0.90464,
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0.93341,
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0.96287,
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0.99304,
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1.02393,
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1.05555,
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1.08791,
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1.12102,
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1.1549,
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1.18955,
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1.225
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]
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self.densityModel = scipy.interpolate.interp1d(altitudes, densities)
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def calculateTAS(self, altitude : int, ias : int):
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if altitude >= 50000:
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altitude = 49999
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if altitude <= 0:
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altitude = 1
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# calculation based on https://aerotoolbox.com/airspeed-conversions/
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return ias * math.sqrt(1.225 / self.densityModel(altitude).item())
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def updateWindModel(self):
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if None == self.LastWeatherUpdate or self.LastWeatherUpdate != self.Weather.Provider.UpdateTime:
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self.LastWeatherUpdate = self.Weather.Provider.UpdateTime
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self.MinimumAltitude = 1000000
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self.MaximumAltitude = -1
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self.WindDirectionModel = None
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self.WindSpeedModel = None
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if None != self.Weather.Provider.WindData and self.Gafor in self.Weather.Provider.WindData:
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altitudes = []
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directions = []
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speeds = []
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# collect the data for the wind model
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for level in self.Weather.Provider.WindData[self.Gafor]:
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altitudes.append(level[0])
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directions.append(level[1])
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speeds.append(level[2])
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# define the thresholds for later boundary checks
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if self.MinimumAltitude > level[0]:
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self.MinimumAltitude = level[0]
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if self.MaximumAltitude < level[0]:
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self.MaximumAltitude = level[0]
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# calculate the models
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if 1 < len(altitudes):
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self.WindDirectionModel = scipy.interpolate.interp1d(altitudes, directions)
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self.WindSpeedModel = scipy.interpolate.interp1d(altitudes, speeds)
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def calculateGS(self, altitude : int, ias : int, heading : int):
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self.updateWindModel()
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tas = self.calculateTAS(altitude, ias)
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# initialize the wind data
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if None != self.WindDirectionModel and None != self.WindSpeedModel:
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direction = 0.0
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speed = 0.0
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if None != self.WindSpeedModel and None != self.WindDirectionModel:
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if self.MaximumAltitude <= altitude:
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altitude = self.MaximumAltitude - 1
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if self.MinimumAltitude >= altitude:
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altitude = self.MinimumAltitude + 1
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direction = self.WindDirectionModel(altitude).item()
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speed = self.WindSpeedModel(altitude).item()
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else:
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speed = 0
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direction = 0
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# calculate the ground speed based on the headwind component
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return tas + speed * math.cos(math.radians(direction) - math.radians(heading))
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