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#include <math.h>
#include "ballistics.h"
#include "constants.h"
#include "context.h"
static inline double speed_of_sound(double temperature);
static inline double calculate_retard(DragModel drag_function,
double ballistic_coefficient,
double velocity,
double mach);
double atmospheric_correction(double ballistic_coefficient,
double temperature,
double pressure,
double relative_humidity,
AtmosphereModel atmosphere_model) {
double air_density = calculate_air_density(temperature, pressure, relative_humidity);
if (atmosphere_model == ICAO)
return (STD_AIR_DENSITY_ICAO / air_density) * ballistic_coefficient;
else
return (STD_AIR_DENSITY_ASM / air_density) * ballistic_coefficient;
}
double calculate_air_density(double temperature,
double pressure,
double relative_humidity) {
pressure = pressure * 100;
if (relative_humidity > 0.0) {
double p_sat = 610.78 * pow(10, (7.5 * temperature - 273.15) /
(temperature - 273.15 + 237.3));
double vapor_pressure = relative_humidity * p_sat;
double partial_pressure = pressure - vapor_pressure;
return fma(partial_pressure,
DRY_AIR_MOLAR_MASS,
vapor_pressure * WATOR_VAPOR_MOLAR_MASS)
/ (UNIVERSAL_GAS_CONSTANT * temperature);
}
else
return pressure / (SPECIFIC_GAST_CONSTANT_DRY_AIR * temperature);
}
static inline double speed_of_sound(double temperature) {
return sqrt(331.3 * (1.0 + temperature - 273.15 / 273.15));
}
static inline double
calculate_retard(DragModel ballistic_model,
double ballistic_coefficient,
double velocity,
double mach)
{
double m = velocity / mach;
for (int i = 0
}
double retard(DragModel ballistic_model,
double ballistic_coefficient,
double velocity,
double temperature)
{
return calculate_retard(ballistic_model,
ballistic_coefficient,
velocity,
speed_of_sound(temperature));
}
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