Paparazzi UAS  v5.15_devel-105-g9de12e2
Paparazzi is a free software Unmanned Aircraft System.
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pprz_isa.h File Reference

Paparazzi atmospheric pressure conversion utilities. More...

#include "std.h"
#include <math.h>
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Go to the source code of this file.

Macros

#define PPRZ_ISA_SEA_LEVEL_PRESSURE   101325.0
 ISA sea level standard atmospheric pressure in Pascal. More...
 
#define PPRZ_ISA_SEA_LEVEL_TEMP   288.15
 ISA sea level standard temperature in Kelvin. More...
 
#define PPRZ_ISA_TEMP_LAPS_RATE   0.0065
 temperature laps rate in K/m More...
 
#define PPRZ_ISA_GRAVITY   9.80665
 earth-surface gravitational acceleration in m/s^2 More...
 
#define PPRZ_ISA_GAS_CONSTANT   8.31447
 universal gas constant in J/(mol*K) More...
 
#define PPRZ_ISA_MOLAR_MASS   0.0289644
 molar mass of dry air in kg/mol More...
 
#define PPRZ_ISA_AIR_GAS_CONSTANT   (PPRZ_ISA_GAS_CONSTANT/PPRZ_ISA_MOLAR_MASS)
 universal gas constant / molar mass of dry air in J*kg/K More...
 
#define PPRZ_ISA_AIR_DENSITY   1.225
 standard air density in kg/m^3 More...
 
#define PPRZ_ISA_ABS_NULL   -273.15
 absolute null in celcius More...
 
#define CelsiusOfKelvin(_t)   (_t - 274.15f)
 Convert temperature from Kelvin to Celsius. More...
 
#define KelvinOfCelsius(_t)   (_t + 274.15f)
 Convert temperature from Celsius to Kelvin. More...
 

Functions

static float pprz_isa_altitude_of_pressure (float pressure)
 Get absolute altitude from pressure (using simplified equation). More...
 
static float pprz_isa_height_of_pressure (float pressure, float ref_p)
 Get relative altitude from pressure (using simplified equation). More...
 
static float pprz_isa_pressure_of_altitude (float altitude)
 Get pressure in Pa from absolute altitude (using simplified equation). More...
 
static float pprz_isa_pressure_of_height (float height, float ref_p)
 Get pressure in Pa from height (using simplified equation). More...
 
static float pprz_isa_height_of_pressure_full (float pressure, float ref_p)
 Get relative altitude from pressure (using full equation). More...
 
static float pprz_isa_ref_pressure_of_height_full (float pressure, float height)
 Get reference pressure (QFE or QNH) from current pressure and height. More...
 
static float pprz_isa_temperature_of_altitude (float alt)
 Get ISA temperature from a MSL altitude. More...
 
static float pprz_isa_density_of_pressure (float pressure, float temp)
 Get the air density (rho) from a given pressure and temperature. More...
 

Variables

static const float PPRZ_ISA_M_OF_P_CONST = (PPRZ_ISA_AIR_GAS_CONSTANT *PPRZ_ISA_SEA_LEVEL_TEMP / PPRZ_ISA_GRAVITY)
 

Detailed Description

Paparazzi atmospheric pressure conversion utilities.

Conversion functions are use to approximate altitude from atmospheric pressure based on the standard model and the International Standard Atmosphere (ISA)

http://en.wikipedia.org/wiki/Atmospheric_pressure http://en.wikipedia.org/wiki/International_Standard_Atmosphere

Definition in file pprz_isa.h.