Air Data interface. More...

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

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Macros
#define	AIR_DATA_BARO_ABS_ID ABI_BROADCAST
	ABI binding for absolute pressure.

#define	AIR_DATA_BARO_DIFF_ID ABI_BROADCAST
	ABI binding for differential pressure.

#define	AIR_DATA_TEMPERATURE_ID ABI_BROADCAST
	ABI binding for temperature.

#define	AIR_DATA_AIRSPEED_ID ABI_BROADCAST
	ABI binding for airspeed.

#define	AIR_DATA_INCIDENCE_ID ABI_BROADCAST
	ABI binding for incidence angles.

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

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

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

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

Functions
static void	pressure_abs_cb (uint8_t sender_id, uint32_t stamp, 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.

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

void	air_data_periodic (void)
	Check health.

void	air_data_parse_WIND_INFO (struct link_device dev, struct transport_tx trans, uint8_t *buf)
	Parse datalink wind info message.

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

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

static void	compute_tas_factor (void)
	Internal utility function to compute current tas factor if needed.

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

float	eas_from_tas (float tas)
	Calculate equivalent airspeed from true airspeed.

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

Variables
struct AirData	air_data
	global AirData state

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

Detailed Description

Air Data interface.

pressures
airspeed
angle of attack and sideslip
wind

Definition in file air_data.c.

Macro Definition Documentation

◆ AIR_DATA_AIRSPEED_ID

#define AIR_DATA_AIRSPEED_ID ABI_BROADCAST

ABI binding for airspeed.

Definition at line 67 of file air_data.c.

◆ AIR_DATA_BARO_ABS_ID

#define AIR_DATA_BARO_ABS_ID ABI_BROADCAST

ABI binding for absolute pressure.

Definition at line 46 of file air_data.c.

◆ AIR_DATA_BARO_DIFF_ID

#define AIR_DATA_BARO_DIFF_ID ABI_BROADCAST

ABI binding for differential pressure.

Definition at line 53 of file air_data.c.

◆ AIR_DATA_CALC_AIRSPEED

#define AIR_DATA_CALC_AIRSPEED TRUE

Calculate Airspeed from differential pressure by default.

Definition at line 85 of file air_data.c.

◆ AIR_DATA_CALC_AMSL_BARO

#define AIR_DATA_CALC_AMSL_BARO FALSE

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

Definition at line 95 of file air_data.c.

◆ AIR_DATA_CALC_TAS_FACTOR

#define AIR_DATA_CALC_TAS_FACTOR TRUE

Calculate tas_factor from temp and pressure by default.

Definition at line 90 of file air_data.c.

◆ AIR_DATA_INCIDENCE_ID

#define AIR_DATA_INCIDENCE_ID ABI_BROADCAST

ABI binding for incidence angles.

Definition at line 74 of file air_data.c.

◆ AIR_DATA_TAS_FACTOR

#define AIR_DATA_TAS_FACTOR 1.0

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

Definition at line 80 of file air_data.c.

◆ AIR_DATA_TEMPERATURE_ID

#define AIR_DATA_TEMPERATURE_ID ABI_BROADCAST

ABI binding for temperature.

Definition at line 60 of file air_data.c.

Function Documentation

◆ air_data_get_amsl()

float air_data_get_amsl ( void )

Return AMSL (altitude AboveSeaLevel).

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

Definition at line 259 of file air_data.c.

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

Referenced by compute_tas_factor().

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◆ air_data_init()

void air_data_init ( void )

AirData initialization.

Called at startup. Bind ABI messages

Definition at line 218 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(), airspeed_ev, AirData::amsl_baro, AirData::amsl_baro_valid, AirData::aoa, baro_health_counter, AirData::calc_airspeed, AirData::calc_amsl_baro, AirData::calc_qnh_once, AirData::calc_tas_factor, DefaultPeriodic, AirData::differential, foo, incidence_cb(), incidence_ev, AirData::pressure, pressure_abs_cb(), pressure_abs_ev, pressure_diff_cb(), pressure_diff_ev, AirData::qnh, register_periodic_telemetry(), send_air_data(), send_amsl(), send_baro_raw(), AirData::sideslip, AirData::tas, AirData::tas_factor, AirData::temperature, temperature_cb(), temperature_ev, AirData::wind_dir, and AirData::wind_speed.

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◆ air_data_parse_WIND_INFO()

void air_data_parse_WIND_INFO	(	struct link_device *	dev,
		struct transport_tx *	trans,
		uint8_t *	buf
	)

Parse datalink wind info message.

Definition at line 279 of file air_data.c.

References air_data, AirData::airspeed, dev, eas_from_tas(), float_vect2_norm(), foo, stateGetAirspeed_f(), stateSetAirspeed_f(), stateSetHorizontalWindspeed_f(), stateSetVerticalWindspeed_f(), AirData::tas, AirData::wind_dir, AirData::wind_speed, FloatVect2::x, and FloatVect2::y.

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◆ air_data_periodic()

void air_data_periodic ( void )

Check health.

Needs to be called periodically.

Definition at line 269 of file air_data.c.

References air_data, AirData::amsl_baro_valid, and baro_health_counter.

◆ airspeed_cb()

static void airspeed_cb	(	uint8_t	sender_id,
		float	eas
	)

static

Definition at line 163 of file air_data.c.

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

Referenced by air_data_init().

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◆ compute_tas_factor()

static void compute_tas_factor ( void )

static

Internal utility function to compute current tas factor if needed.

Definition at line 368 of file air_data.c.

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

Referenced by eas_from_tas(), and tas_from_eas().

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◆ eas_from_dynamic_pressure()

float eas_from_dynamic_pressure ( float q )

Calculate equivalent airspeed from dynamic pressure.

Dynamic pressure (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 322 of file air_data.c.

References foo, PPRZ_ISA_AIR_DENSITY, and sign().

Referenced by pressure_diff_cb(), and tas_from_dynamic_pressure().

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◆ eas_from_tas()

float eas_from_tas ( float tas )

Calculate equivalent airspeed from true airspeed.

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

Parameters

tas	true airspeed (TAS) in m/s

Returns: equivalent airspeed in m/s

Definition at line 410 of file air_data.c.

References air_data, compute_tas_factor(), and AirData::tas_factor.

Referenced by air_data_parse_WIND_INFO(), and wind_estimation_quadrotor_periodic().

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◆ get_tas_factor()

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 355 of file air_data.c.

References foo, KelvinOfCelsius, p, PPRZ_ISA_SEA_LEVEL_PRESSURE, and PPRZ_ISA_SEA_LEVEL_TEMP.

Referenced by compute_tas_factor(), and temperature_cb().

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◆ incidence_cb()

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

static

Definition at line 174 of file air_data.c.

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

Referenced by air_data_init().

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◆ pressure_abs_cb()

static void pressure_abs_cb	(	uint8_t	sender_id,
		uint32_t	stamp,
		float	pressure
	)

static

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

Definition at line 114 of file air_data.c.

References air_data, LlaCoor_f::alt, AirData::amsl_baro, AirData::amsl_baro_valid, baro_health_counter, AirData::calc_amsl_baro, AirData::calc_qnh_once, foo, h(), State::ned_initialized_f, pprz_isa_height_of_pressure_full(), pprz_isa_ref_pressure_of_height_full(), AirData::pressure, AirData::qnh, state, stateGetHmslOrigin_f(), stateGetLlaOrigin_f(), stateGetPositionLla_f(), and stateIsGlobalCoordinateValid().

Referenced by air_data_init().

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◆ pressure_diff_cb()

static void pressure_diff_cb	(	uint8_t	sender_id,
		float	pressure
	)

static

Definition at line 141 of file air_data.c.

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

Referenced by air_data_init().

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◆ send_air_data()

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

static

Definition at line 197 of file air_data.c.

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

Referenced by air_data_init().

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◆ send_amsl()

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

static

Definition at line 206 of file air_data.c.

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

Referenced by air_data_init().

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◆ send_baro_raw()

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

static

Definition at line 191 of file air_data.c.

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

Referenced by air_data_init().

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◆ tas_from_dynamic_pressure()

float tas_from_dynamic_pressure ( float q )

Calculate true airspeed from dynamic pressure.

Dynamic pressure (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 424 of file air_data.c.

References eas_from_dynamic_pressure(), and tas_from_eas().

Referenced by pressure_diff_cb().

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◆ tas_from_eas()

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 395 of file air_data.c.

References air_data, compute_tas_factor(), foo, and AirData::tas_factor.

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

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◆ temperature_cb()

static void temperature_cb	(	uint8_t	sender_id,
		float	temp
	)

static

Definition at line 153 of file air_data.c.

References air_data, AirData::airspeed, baro_health_counter, 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

◆ air_data

struct AirData air_data

global AirData state

Definition at line 41 of file air_data.c.

Referenced by air_data_get_amsl(), air_data_init(), air_data_parse_WIND_INFO(), air_data_periodic(), airspeed_cb(), compute_tas_factor(), eas_from_tas(), incidence_cb(), pressure_abs_cb(), pressure_diff_cb(), save_speeds(), send_air_data(), send_amsl(), send_baro_raw(), send_windtunnel_meas(), tas_from_eas(), and temperature_cb().

◆ airspeed_ev

abi_event airspeed_ev

static

Definition at line 69 of file air_data.c.

Referenced by air_data_init().

◆ baro_health_counter

uint8_t baro_health_counter

static

counter to check baro health

Definition at line 111 of file air_data.c.

Referenced by air_data_init(), air_data_periodic(), pressure_abs_cb(), and temperature_cb().

◆ incidence_ev

abi_event incidence_ev

static

Definition at line 76 of file air_data.c.

Referenced by air_data_init().

◆ pressure_abs_ev

abi_event pressure_abs_ev

static

Definition at line 48 of file air_data.c.

Referenced by air_data_init().

◆ pressure_diff_ev

abi_event pressure_diff_ev

static

Definition at line 55 of file air_data.c.

Referenced by air_data_init().

◆ temperature_ev

abi_event temperature_ev

static

Definition at line 62 of file air_data.c.

Referenced by air_data_init().

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ 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

Function Documentation

◆ air_data_get_amsl()

◆ air_data_init()

◆ air_data_parse_WIND_INFO()

◆ air_data_periodic()

◆ airspeed_cb()

◆ compute_tas_factor()

◆ eas_from_dynamic_pressure()

◆ eas_from_tas()

◆ get_tas_factor()

◆ incidence_cb()

◆ pressure_abs_cb()

◆ pressure_diff_cb()

◆ send_air_data()

◆ send_amsl()

◆ send_baro_raw()

◆ tas_from_dynamic_pressure()

◆ tas_from_eas()

◆ temperature_cb()

Variable Documentation

◆ air_data

◆ airspeed_ev

◆ baro_health_counter

◆ incidence_ev

◆ pressure_abs_ev

◆ pressure_diff_ev

◆ temperature_ev