#include <simgear/constants.h>
#include <simgear/debug/logstream.hxx>
+#include <simgear/math/interpolater.hxx>
#include <Main/fg_props.hxx>
#include "environment.hxx"
FGEnvironment::FGEnvironment()
- : visibility_m(32000),
+ : _temperature_degc_table(new SGInterpTable),
+ _pressure_inhg_table(new SGInterpTable),
+ _density_slugft3_table(new SGInterpTable),
+ visibility_m(32000),
temperature_sea_level_degc(20),
pressure_sea_level_inhg(28),
+ density_sea_level_slugft3(0.0024),
wind_from_heading_deg(0),
wind_speed_kt(0),
wind_from_north_fps(0),
wind_from_east_fps(0),
wind_from_down_fps(0)
{
+ _setup_tables();
}
FGEnvironment::FGEnvironment (const FGEnvironment &env)
- : elevation_ft(env.elevation_ft),
+ : _temperature_degc_table(new SGInterpTable),
+ _pressure_inhg_table(new SGInterpTable),
+ _density_slugft3_table(new SGInterpTable),
+ elevation_ft(env.elevation_ft),
visibility_m(env.visibility_m),
temperature_sea_level_degc(env.temperature_sea_level_degc),
pressure_sea_level_inhg(env.pressure_sea_level_inhg),
+ density_sea_level_slugft3(env.density_sea_level_slugft3),
wind_from_heading_deg(env.wind_from_heading_deg),
wind_speed_kt(env.wind_speed_kt),
wind_from_north_fps(env.wind_from_north_fps),
wind_from_east_fps(env.wind_from_east_fps),
wind_from_down_fps(env.wind_from_down_fps)
{
+ _setup_tables();
}
FGEnvironment::~FGEnvironment()
{
+ delete _temperature_degc_table;
+ delete _pressure_inhg_table;
+ delete _density_slugft3_table;
}
return pressure_inhg;
}
+double
+FGEnvironment::get_density_sea_level_slugft3 () const
+{
+ return density_sea_level_slugft3;
+}
+
+double
+FGEnvironment::get_density_slugft3 () const
+{
+ return density_slugft3;
+}
+
double
FGEnvironment::get_wind_from_heading_deg () const
{
return elevation_ft;
}
-
-
void
FGEnvironment::set_visibility_m (double v)
{
FGEnvironment::set_temperature_sea_level_degc (double t)
{
temperature_sea_level_degc = t;
- _recalc_alt_temp();
+ _recalc_alt_temperature();
}
void
FGEnvironment::set_temperature_degc (double t)
{
temperature_degc = t;
- _recalc_sl_temp();
+ _recalc_sl_temperature();
}
void
FGEnvironment::set_pressure_sea_level_inhg (double p)
{
pressure_sea_level_inhg = p;
- _recalc_alt_press();
+ _recalc_alt_pressure();
}
void
FGEnvironment::set_pressure_inhg (double p)
{
pressure_inhg = p;
- _recalc_sl_press();
+ _recalc_sl_pressure();
+}
+
+void
+FGEnvironment::set_density_sea_level_slugft3 (double d)
+{
+ density_sea_level_slugft3 = d;
+ _recalc_alt_density();
+}
+
+void
+FGEnvironment::set_density_slugft3 (double d)
+{
+ density_slugft3 = d;
+ _recalc_sl_density();
}
void
FGEnvironment::set_elevation_ft (double e)
{
elevation_ft = e;
- _recalc_alt_temp();
- _recalc_alt_press();
+ _recalc_alt_temperature();
+ _recalc_alt_pressure();
+ _recalc_alt_density();
+}
+
+// Atmosphere model.
+
+// Copied from YASim Atmosphere.cxx, with m converted to ft, degK
+// converted to degC, Pa converted to inHG, and kg/m^3 converted to
+// slug/ft^3.
+
+// Original comment from YASim:
+
+// Copied from McCormick, who got it from "The ARDC Model Atmosphere"
+// Note that there's an error in the text in the first entry,
+// McCormick lists 299.16/101325/1.22500, but those don't agree with
+// R=287. I chose to correct the temperature to 288.20, since 79F is
+// pretty hot for a "standard" atmosphere.
+
+// Elevation (ft), temperature (degC), pressure (inHG), density (slug/ft^3)
+static double atmosphere_data[][4] = {
+ 0, 0.00, 0.000, 0.000000,
+ 2952, -5.89, -3.058, -0.000198,
+ 5905, -11.74, -5.856, -0.000384,
+ 8858, -17.58, -8.413, -0.000556,
+ 11811, -23.43, -10.745, -0.000717,
+ 14763, -29.27, -12.867, -0.000867,
+ 17716, -35.11, -14.794, -0.001006,
+ 20669, -40.95, -16.541, -0.001136,
+ 23622, -46.79, -18.120, -0.001255,
+ 26574, -52.62, -19.544, -0.001366,
+ 29527, -58.46, -20.826, -0.001467,
+ 32480, -64.29, -21.976, -0.001561,
+ 35433, -70.12, -23.005, -0.001647,
+ 38385, -71.54, -23.916, -0.001739,
+ 41338, -71.54, -24.708, -0.001822,
+ 44291, -71.54, -25.395, -0.001894,
+ 47244, -71.54, -25.991, -0.001957,
+ 50196, -71.54, -26.509, -0.002012,
+ 53149, -71.54, -26.959, -0.002059,
+ 56102, -71.54, -27.349, -0.002100,
+ 59055, -71.54, -27.687, -0.002136,
+ 62007, -71.54, -27.981, -0.002167,
+ -1, -1, -1, -1
+};
+
+void
+FGEnvironment::_setup_tables ()
+{
+ for (int i = 0; atmosphere_data[i][0] != -1; i++) {
+ _temperature_degc_table->addEntry(atmosphere_data[i][0],
+ atmosphere_data[i][1]);
+ _pressure_inhg_table->addEntry(atmosphere_data[i][0],
+ atmosphere_data[i][2]);
+ _density_slugft3_table->addEntry(atmosphere_data[i][0],
+ atmosphere_data[i][3]);
+ }
}
void
}
void
-FGEnvironment::_recalc_sl_temp ()
+FGEnvironment::_recalc_sl_temperature ()
{
- // Earth atmosphere model from
- // http://www.grc.nasa.gov/WWW/K-12/airplane/atmos.html
-
- // Stratospheric temperatures are not really reversible, so use 15degC.
-
- if (elevation_ft < 36152) // Troposphere
+ if (elevation_ft < 38000) {
temperature_sea_level_degc =
- temperature_degc + (.00649 * SG_FEET_TO_METER * elevation_ft);
+ temperature_degc - _temperature_degc_table->interpolate(elevation_ft);
+ }
// If we're in the stratosphere, leave sea-level temp alone
}
void
-FGEnvironment::_recalc_alt_temp ()
+FGEnvironment::_recalc_alt_temperature ()
{
- // Earth atmosphere model from
- // http://www.grc.nasa.gov/WWW/K-12/airplane/atmos.html
+ temperature_degc =
+ temperature_sea_level_degc +
+ _temperature_degc_table->interpolate(elevation_ft);
+}
- if (elevation_ft < 36152) // Troposphere
- temperature_degc =
- temperature_sea_level_degc - (.00649 * SG_FEET_TO_METER * elevation_ft);
- else if (elevation_ft < 82345) // Lower Stratosphere
- temperature_degc = -56.46;
- else
- temperature_degc = -131.21 + (.00299 * SG_FEET_TO_METER * elevation_ft);
+void
+FGEnvironment::_recalc_sl_pressure ()
+{
+ pressure_sea_level_inhg =
+ pressure_inhg - _pressure_inhg_table->interpolate(elevation_ft);
}
void
-FGEnvironment::_recalc_sl_press ()
+FGEnvironment::_recalc_alt_pressure ()
{
- // FIXME: calculate properly
- pressure_sea_level_inhg = pressure_inhg;
+ pressure_inhg =
+ pressure_sea_level_inhg + _pressure_inhg_table->interpolate(elevation_ft);
}
void
-FGEnvironment::_recalc_alt_press ()
+FGEnvironment::_recalc_sl_density ()
{
- // FIXME: calculate properly
- pressure_inhg = pressure_sea_level_inhg;
+ density_sea_level_slugft3 =
+ density_slugft3 - _density_slugft3_table->interpolate(elevation_ft);
}
-// end of environment.cxx
+void
+FGEnvironment::_recalc_alt_density ()
+{
+ density_slugft3 =
+ density_sea_level_slugft3 +
+ _density_slugft3_table->interpolate(elevation_ft);
+}
+// end of environment.cxx
# include <math.h>
#endif
+class SGInterpTable;
+
/**
* Model the natural environment.
virtual ~FGEnvironment();
virtual double get_visibility_m () const;
+
virtual double get_temperature_sea_level_degc () const;
virtual double get_temperature_degc () const;
virtual double get_pressure_sea_level_inhg () const;
virtual double get_pressure_inhg () const;
+ virtual double get_density_sea_level_slugft3 () const;
+ virtual double get_density_slugft3 () const;
+
virtual double get_wind_from_heading_deg () const;
virtual double get_wind_speed_kt () const;
virtual double get_wind_from_north_fps () const;
virtual double get_wind_from_down_fps () const;
virtual void set_visibility_m (double v);
+
virtual void set_temperature_sea_level_degc (double t);
virtual void set_temperature_degc (double t);
virtual void set_pressure_sea_level_inhg (double p);
virtual void set_pressure_inhg (double p);
+ virtual void set_density_sea_level_slugft3 (double d);
+ virtual void set_density_slugft3 (double d);
+
virtual void set_wind_from_heading_deg (double h);
virtual void set_wind_speed_kt (double s);
virtual void set_wind_from_north_fps (double n);
private:
+ void _setup_tables ();
+
void _recalc_hdgspd ();
void _recalc_ne ();
- void _recalc_sl_temp ();
- void _recalc_alt_temp ();
- void _recalc_sl_press ();
- void _recalc_alt_press ();
+
+ void _recalc_sl_temperature ();
+ void _recalc_alt_temperature ();
+ void _recalc_sl_pressure ();
+ void _recalc_alt_pressure ();
+ void _recalc_sl_density ();
+ void _recalc_alt_density ();
+
+ SGInterpTable * _temperature_degc_table;
+ SGInterpTable * _pressure_inhg_table;
+ SGInterpTable * _density_slugft3_table;
double elevation_ft;
double visibility_m;
+
+ // Atmosphere
double temperature_sea_level_degc;
double temperature_degc;
double pressure_sea_level_inhg;
double pressure_inhg;
+ double density_sea_level_slugft3;
+ double density_slugft3;
double wind_from_heading_deg;
double wind_speed_kt;
projects / flightgear.git / commitdiff