Air Data interface. More...

#include "modules/air_data/air_data.h"
#include "subsystems/abi.h"
#include "math/pprz_isa.h"
#include "state.h"
#include "generated/airframe.h"
#include "subsystems/datalink/telemetry.h"

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Macros
#define	AIR_DATA_BARO_ABS_ID ABI_BROADCAST
	ABI binding for absolute pressure. More...

#define	AIR_DATA_BARO_DIFF_ID ABI_BROADCAST
	ABI binding for differential pressure. More...

#define	AIR_DATA_TEMPERATURE_ID ABI_BROADCAST
	ABI binding for temperature. More...

#define	AIR_DATA_AIRSPEED_ID ABI_BROADCAST
	ABI binding for airspeed. More...

#define	AIR_DATA_INCIDENCE_ID ABI_BROADCAST
	ABI binding for incidence angles. More...

#define	AIR_DATA_TAS_FACTOR 1.0
	Default factor to convert estimated airspeed (EAS) to true airspeed (TAS) More...

#define	AIR_DATA_CALC_AIRSPEED TRUE
	Calculate Airspeed from differential pressure by default. More...

#define	AIR_DATA_CALC_TAS_FACTOR TRUE
	Calculate tas_factor from temp and pressure by default. More...

#define	AIR_DATA_CALC_AMSL_BARO FALSE
	Don't calculate AMSL from baro and QNH by default. More...

Functions
static void	pressure_abs_cb (uint8_t sender_id, float pressure)

static void	pressure_diff_cb (uint8_t sender_id, float pressure)

static void	temperature_cb (uint8_t sender_id, float temp)

static void	airspeed_cb (uint8_t sender_id, float eas)

static void	incidence_cb (uint8_t sender_id, uint8_t flag, float aoa, float sideslip)

static void	send_baro_raw (struct transport_tx trans, struct link_device dev)

static void	send_air_data (struct transport_tx trans, struct link_device dev)

static void	send_amsl (struct transport_tx trans, struct link_device dev)

void	air_data_init (void)
	AirData initialization. More...

float	air_data_get_amsl (void)
	Return AMSL (altitude AboveSeaLevel). More...

void	air_data_periodic (void)
	Check health. More...

float	eas_from_dynamic_pressure (float q)
	Calculate equivalent airspeed from dynamic pressure. More...

float	get_tas_factor (float p, float t)
	Calculate true airspeed (TAS) factor. More...

float	tas_from_eas (float eas)
	Calculate true airspeed from equivalent airspeed. More...

float	tas_from_dynamic_pressure (float q)
	Calculate true airspeed from dynamic pressure. More...

Variables
struct AirData	air_data
	global AirData state More...

static abi_event	pressure_abs_ev

static abi_event	pressure_diff_ev

static abi_event	temperature_ev

static abi_event	airspeed_ev

static abi_event	incidence_ev

static uint8_t	baro_health_counter
	counter to check baro health More...

Detailed Description

Air Data interface.

pressures
airspeed
angle of attack and sideslip
wind

Definition in file air_data.c.

Macro Definition Documentation

#define AIR_DATA_AIRSPEED_ID ABI_BROADCAST

ABI binding for airspeed.

Definition at line 65 of file air_data.c.

Referenced by air_data_init().

#define AIR_DATA_BARO_ABS_ID ABI_BROADCAST

ABI binding for absolute pressure.

Definition at line 44 of file air_data.c.

Referenced by air_data_init().

#define AIR_DATA_BARO_DIFF_ID ABI_BROADCAST

ABI binding for differential pressure.

Definition at line 51 of file air_data.c.

Referenced by air_data_init().

#define AIR_DATA_CALC_AIRSPEED TRUE

Calculate Airspeed from differential pressure by default.

Definition at line 83 of file air_data.c.

Referenced by air_data_init().

#define AIR_DATA_CALC_AMSL_BARO FALSE

Don't calculate AMSL from baro and QNH by default.

Definition at line 93 of file air_data.c.

Referenced by air_data_init().

#define AIR_DATA_CALC_TAS_FACTOR TRUE

Calculate tas_factor from temp and pressure by default.

Definition at line 88 of file air_data.c.

Referenced by air_data_init().

#define AIR_DATA_INCIDENCE_ID ABI_BROADCAST

ABI binding for incidence angles.

Definition at line 72 of file air_data.c.

Referenced by air_data_init().

#define AIR_DATA_TAS_FACTOR 1.0

Default factor to convert estimated airspeed (EAS) to true airspeed (TAS)

Definition at line 78 of file air_data.c.

Referenced by air_data_init().

#define AIR_DATA_TEMPERATURE_ID ABI_BROADCAST

ABI binding for temperature.

Definition at line 58 of file air_data.c.

Referenced by air_data_init().

Function Documentation

float air_data_get_amsl ( void )

Return AMSL (altitude AboveSeaLevel).

If AMSL from baro is valid, return that, otherwise from gps.

Definition at line 257 of file air_data.c.

References air_data, LlaCoor_f::alt, AirData::amsl_baro, AirData::amsl_baro_valid, and stateGetPositionLla_f().

Referenced by tas_from_eas().

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void air_data_init ( void )

AirData initialization.

Called at startup. Bind ABI messages

Definition at line 216 of file air_data.c.

References air_data, AIR_DATA_AIRSPEED_ID, AIR_DATA_BARO_ABS_ID, AIR_DATA_BARO_DIFF_ID, AIR_DATA_CALC_AIRSPEED, AIR_DATA_CALC_AMSL_BARO, AIR_DATA_CALC_TAS_FACTOR, AIR_DATA_INCIDENCE_ID, AIR_DATA_TAS_FACTOR, AIR_DATA_TEMPERATURE_ID, AirData::airspeed, airspeed_cb(), AirData::amsl_baro, AirData::amsl_baro_valid, AirData::aoa, AirData::calc_airspeed, AirData::calc_amsl_baro, AirData::calc_qnh_once, AirData::calc_tas_factor, DefaultPeriodic, AirData::differential, incidence_cb(), AirData::pressure, pressure_abs_cb(), pressure_diff_cb(), AirData::qnh, register_periodic_telemetry(), send_air_data(), send_amsl(), send_baro_raw(), AirData::sideslip, AirData::tas, AirData::tas_factor, AirData::temperature, temperature_cb(), AirData::wind_dir, and AirData::wind_speed.

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void air_data_periodic ( void )

Check health.

Needs to be called periodically.

Definition at line 267 of file air_data.c.

References air_data, and AirData::amsl_baro_valid.

static void airspeed_cb	(	uint8_t	sender_id,
		float	eas
	)

static

Definition at line 161 of file air_data.c.

References air_data, AirData::airspeed, AirData::calc_airspeed, stateSetAirspeed_f(), AirData::tas, and tas_from_eas().

Referenced by air_data_init().

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float eas_from_dynamic_pressure ( float q )

Calculate equivalent airspeed from dynamic pressure.

Dynamic pressure $q$ (also called impact pressure) is the difference between total(pitot) and static pressure.

Airspeed from dynamic pressure:

$v = \frac12 \sqrt{\frac{2q}{\rho}}$

with $\rho$ as air density. Using standard sea level air density $\rho_0$ gives you equivalent airspeed (EAS).

Parameters

q	dynamic pressure in Pa

Returns: equivalent airspeed in m/s

Definition at line 291 of file air_data.c.

References Max, and PPRZ_ISA_AIR_DENSITY.

Referenced by pressure_diff_cb(), and tas_from_dynamic_pressure().

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float get_tas_factor	(	float	p,
		float	t
	)

Calculate true airspeed (TAS) factor.

TAS = tas_factor * EAS

True airspeed (TAS) from equivalent airspeed (EAS):

$\mbox{TAS} = \mbox{EAS} \sqrt{\frac{\rho_0}{\rho}}$

and $\frac{\rho_0}{\rho} = \frac{p_0T}{pT_0}$ where

is the air pressure at the flight condition
is the air pressure at sea level = 101325 Pa
is the air temperature at the flight condition
is the air temperature at sea level = 288.15 K

Parameters

p	current air pressure in Pa
t	current air temperature in degrees Celcius

Returns: tas factor

Definition at line 319 of file air_data.c.

References KelvinOfCelsius, PPRZ_ISA_SEA_LEVEL_PRESSURE, and PPRZ_ISA_SEA_LEVEL_TEMP.

Referenced by tas_from_eas(), and temperature_cb().

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static void incidence_cb	(	uint8_t	sender_id,
		uint8_t	flag,
		float	aoa,
		float	sideslip
	)

static

Definition at line 172 of file air_data.c.

References air_data, AirData::aoa, AirData::sideslip, stateSetAngleOfAttack_f(), and stateSetSideslip_f().

Referenced by air_data_init().

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static void pressure_abs_cb	(	uint8_t	sender_id,
		float	pressure
	)

static

FIXME: use height above MSL (geoid) and not WGS84 ellipsoid here

Definition at line 112 of file air_data.c.

References air_data, LlaCoor_f::alt, AirData::amsl_baro, AirData::amsl_baro_valid, AirData::calc_amsl_baro, AirData::calc_qnh_once, h(), LtpDef_f::hmsl, LtpDef_f::lla, State::ned_initialized_f, State::ned_origin_f, pprz_isa_height_of_pressure_full(), pprz_isa_ref_pressure_of_height_full(), AirData::pressure, AirData::qnh, state, stateGetPositionLla_f(), and stateIsGlobalCoordinateValid().

Referenced by air_data_init().

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static void pressure_diff_cb	(	uint8_t	sender_id,
		float	pressure
	)

static

Definition at line 139 of file air_data.c.

References air_data, AirData::airspeed, AirData::calc_airspeed, AirData::differential, eas_from_dynamic_pressure(), AirData::pressure, stateSetAirspeed_f(), AirData::tas, and tas_from_eas().

Referenced by air_data_init().

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static void send_air_data	(	struct transport_tx *	trans,
		struct link_device *	dev
	)

static

Definition at line 195 of file air_data.c.

References air_data, AirData::airspeed, AirData::amsl_baro, AirData::differential, AirData::pressure, AirData::qnh, AirData::tas, and AirData::temperature.

Referenced by air_data_init().

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static void send_amsl	(	struct transport_tx *	trans,
		struct link_device *	dev
	)

static

Definition at line 204 of file air_data.c.

References air_data, LlaCoor_f::alt, AirData::amsl_baro, and stateGetPositionLla_f().

Referenced by air_data_init().

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static void send_baro_raw	(	struct transport_tx *	trans,
		struct link_device *	dev
	)

static

Definition at line 189 of file air_data.c.

References air_data, AirData::differential, and AirData::pressure.

Referenced by air_data_init().

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float tas_from_dynamic_pressure ( float q )

Calculate true airspeed from dynamic pressure.

Dynamic pressure $q$ (also called impact pressure) is the difference between total(pitot) and static pressure.

Parameters

q	dynamic pressure in Pa

Returns: true airspeed in m/s

Definition at line 365 of file air_data.c.

References eas_from_dynamic_pressure(), and tas_from_eas().

Referenced by pressure_diff_cb().

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float tas_from_eas ( float eas )

Calculate true airspeed from equivalent airspeed.

True airspeed (TAS) from EAS: TAS = air_data.tas_factor * EAS

Parameters

eas	equivalent airspeed (EAS) in m/s

Returns: true airspeed in m/s

Definition at line 338 of file air_data.c.

References air_data, air_data_get_amsl(), AirData::calc_tas_factor, CelsiusOfKelvin, get_tas_factor(), p, pprz_isa_pressure_of_altitude(), pprz_isa_temperature_of_altitude(), AirData::pressure, AirData::tas_factor, and AirData::temperature.

Referenced by airspeed_cb(), pressure_diff_cb(), and tas_from_dynamic_pressure().

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static void temperature_cb	(	uint8_t	sender_id,
		float	temp
	)

static

Definition at line 151 of file air_data.c.

References air_data, AirData::airspeed, AirData::calc_tas_factor, get_tas_factor(), AirData::pressure, AirData::tas_factor, and AirData::temperature.

Referenced by air_data_init().

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Variable Documentation

struct AirData air_data

global AirData state

Definition at line 39 of file air_data.c.

Referenced by air_data_get_amsl(), air_data_init(), air_data_periodic(), airspeed_cb(), incidence_cb(), pressure_abs_cb(), pressure_diff_cb(), send_air_data(), send_amsl(), send_baro_raw(), tas_from_eas(), and temperature_cb().

abi_event airspeed_ev

static

Definition at line 67 of file air_data.c.

uint8_t baro_health_counter

static

counter to check baro health

Definition at line 109 of file air_data.c.

abi_event incidence_ev

static

Definition at line 74 of file air_data.c.

abi_event pressure_abs_ev

static

Definition at line 46 of file air_data.c.

abi_event pressure_diff_ev

static

Definition at line 53 of file air_data.c.

abi_event temperature_ev

static

Definition at line 60 of file air_data.c.

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

Function Documentation

Variable Documentation