Collaboration diagram for International Standard Atmosphere utilities:

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	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...

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

Macro Definition Documentation

#define CelsiusOfKelvin ( _t ) (_t - 274.15f)

Convert temperature from Kelvin to Celsius.

Definition at line 69 of file pprz_isa.h.

Referenced by tas_from_eas().

#define KelvinOfCelsius ( _t ) (_t + 274.15f)

Convert temperature from Celsius to Kelvin.

Definition at line 71 of file pprz_isa.h.

Referenced by get_tas_factor().

#define PPRZ_ISA_AIR_DENSITY 1.225

standard air density in kg/m^3

Definition at line 64 of file pprz_isa.h.

Referenced by eas_from_dynamic_pressure().

#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

Definition at line 62 of file pprz_isa.h.

#define PPRZ_ISA_GAS_CONSTANT 8.31447

universal gas constant in J/(mol*K)

Definition at line 58 of file pprz_isa.h.

Referenced by pprz_isa_height_of_pressure_full(), and pprz_isa_ref_pressure_of_height_full().

#define PPRZ_ISA_GRAVITY 9.80665

earth-surface gravitational acceleration in m/s^2

Definition at line 56 of file pprz_isa.h.

Referenced by pprz_isa_height_of_pressure_full(), and pprz_isa_ref_pressure_of_height_full().

#define PPRZ_ISA_MOLAR_MASS 0.0289644

molar mass of dry air in kg/mol

Definition at line 60 of file pprz_isa.h.

Referenced by pprz_isa_height_of_pressure_full(), and pprz_isa_ref_pressure_of_height_full().

#define PPRZ_ISA_SEA_LEVEL_PRESSURE 101325.0

ISA sea level standard atmospheric pressure in Pascal.

Definition at line 50 of file pprz_isa.h.

Referenced by baro_cb(), get_tas_factor(), nps_fdm_init(), pprz_isa_altitude_of_pressure(), and pprz_isa_pressure_of_altitude().

#define PPRZ_ISA_SEA_LEVEL_TEMP 288.15

ISA sea level standard temperature in Kelvin.

Definition at line 52 of file pprz_isa.h.

Referenced by get_tas_factor(), pprz_isa_height_of_pressure_full(), pprz_isa_ref_pressure_of_height_full(), and pprz_isa_temperature_of_altitude().

#define PPRZ_ISA_TEMP_LAPS_RATE 0.0065

temperature laps rate in K/m

Definition at line 54 of file pprz_isa.h.

Referenced by pprz_isa_height_of_pressure_full(), pprz_isa_ref_pressure_of_height_full(), and pprz_isa_temperature_of_altitude().

Function Documentation

static float pprz_isa_altitude_of_pressure ( float pressure )

inlinestatic

Get absolute altitude from pressure (using simplified equation).

Referrence pressure is standard pressure at sea level

Parameters

pressure current pressure in Pascal (Pa)

Returns: altitude in m in ISA conditions

Definition at line 80 of file pprz_isa.h.

References PPRZ_ISA_SEA_LEVEL_PRESSURE.

Referenced by baro_ms5611_event().

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static float pprz_isa_height_of_pressure	(	float	pressure,
		float	ref_p
	)

inlinestatic

Get relative altitude from pressure (using simplified equation).

Given the current pressure and a reference pressure (at height=0), calculate the height above the reference in meters. If you pass QNH as reference pressure, you get the height above sea level. Using QFE as reference pressure, you get height above the airfield.

Parameters

pressure	current pressure in Pascal (Pa)
ref_p	reference pressure (QFE) when height=0 or QNH at sea level

Returns: height in m above reference in ISA conditions

Definition at line 100 of file pprz_isa.h.

Referenced by baro_cb(), ins_alt_float_update_baro(), and ins_float_invariant_update_baro().

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static float pprz_isa_height_of_pressure_full	(	float	pressure,
		float	ref_p
	)

inlinestatic

Get relative altitude from pressure (using full equation).

Given the current pressure and a reference pressure (at height=0), calculate the height above the reference in meters. If you pass QNH as reference pressure, you get the height above sea level. Using QFE as reference pressure, you get height above the airfield.

Parameters