diff options
| author | Lorenz Meier <lm@inf.ethz.ch> | 2013-01-21 23:45:16 +0100 |
|---|---|---|
| committer | Lorenz Meier <lm@inf.ethz.ch> | 2013-01-21 23:45:16 +0100 |
| commit | 2ebb1812f1eea47f06e79650242416493ce279b9 (patch) | |
| tree | 1957033e730cf778fa85f90036e9f963c8e2d6a6 /apps/systemlib | |
| parent | 48e497e4069a2f8773d90f2d1887967a81e487d8 (diff) | |
| download | px4-firmware-2ebb1812f1eea47f06e79650242416493ce279b9.tar.gz px4-firmware-2ebb1812f1eea47f06e79650242416493ce279b9.tar.bz2 px4-firmware-2ebb1812f1eea47f06e79650242416493ce279b9.zip | |
Implemented airspeed measurement. Untested
Diffstat (limited to 'apps/systemlib')
| -rw-r--r-- | apps/systemlib/Makefile | 3 | ||||
| -rw-r--r-- | apps/systemlib/airspeed.c | 8 | ||||
| -rw-r--r-- | apps/systemlib/airspeed.h | 11 | ||||
| -rw-r--r-- | apps/systemlib/conversions.c | 6 | ||||
| -rw-r--r-- | apps/systemlib/conversions.h | 5 |
5 files changed, 20 insertions, 13 deletions
diff --git a/apps/systemlib/Makefile b/apps/systemlib/Makefile index 942116faa..8240dbe43 100644 --- a/apps/systemlib/Makefile +++ b/apps/systemlib/Makefile @@ -43,7 +43,8 @@ CSRCS = err.c \ conversions.c \ cpuload.c \ getopt_long.c \ - up_cxxinitialize.c + up_cxxinitialize.c \ + airspeed.c # ppm_decode.c \ diff --git a/apps/systemlib/airspeed.c b/apps/systemlib/airspeed.c index e213b66c2..5c68f8ea5 100644 --- a/apps/systemlib/airspeed.c +++ b/apps/systemlib/airspeed.c @@ -41,11 +41,13 @@ */ #include "math.h" +#include "conversions.h" +#include "airspeed.h" float calc_indicated_airspeed(float pressure_front, float pressure_ambient, float temperature) { - return sqrtf((2.0f*(pressure_front - pressure_ambient)) / air_density_sea_level); + return sqrtf((2.0f*(pressure_front - pressure_ambient)) / CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C); } /** @@ -60,7 +62,7 @@ float calc_indicated_airspeed(float pressure_front, float pressure_ambient, floa */ float calc_true_airspeed_from_indicated(float speed, float pressure_ambient, float temperature) { - return speed * sqrtf(air_density_sea_level / get_air_density(pressure_ambient, temperature)); + return speed * sqrtf(CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C / get_air_density(pressure_ambient, temperature)); } /** @@ -76,4 +78,4 @@ float calc_true_airspeed_from_indicated(float speed, float pressure_ambient, flo float calc_true_airspeed(float pressure_front, float pressure_ambient, float temperature) { return sqrtf((2.0f*(pressure_front - pressure_ambient)) / get_air_density(pressure_ambient, temperature)); -}
\ No newline at end of file +} diff --git a/apps/systemlib/airspeed.h b/apps/systemlib/airspeed.h index 62acfe2b0..b1beb79ae 100644 --- a/apps/systemlib/airspeed.h +++ b/apps/systemlib/airspeed.h @@ -33,13 +33,16 @@ ****************************************************************************/ /** - * @file airspeed.c - * Airspeed estimation + * @file airspeed.h + * Airspeed estimation declarations * * @author Lorenz Meier <lm@inf.ethz.ch> * */ +#ifndef AIRSPEED_H_ +#define AIRSPEED_H_ + #include "math.h" #include "conversions.h" @@ -83,4 +86,6 @@ __EXPORT float calc_true_airspeed_from_indicated(float speed, float pressure_amb */ __EXPORT float calc_true_airspeed(float pressure_front, float pressure_ambient, float temperature); -__END_DECLS
\ No newline at end of file +__END_DECLS + +#endif diff --git a/apps/systemlib/conversions.c b/apps/systemlib/conversions.c index fed97f101..2b8003e45 100644 --- a/apps/systemlib/conversions.c +++ b/apps/systemlib/conversions.c @@ -42,10 +42,6 @@ #include "conversions.h" -#define air_gas_constant 8.31432f -#define air_density_sea_level 1.225f -#define absolute_null_kelvin 273.15f - int16_t int16_t_from_bytes(uint8_t bytes[]) { @@ -154,5 +150,5 @@ void quat2rot(const float Q[4], float R[9]) float get_air_density(float static_pressure, float temperature_celsius) { - return static_pressure / (air_gas_constant * (temperature_celsius + absolute_null_kelvin)); + return static_pressure / (CONSTANTS_AIR_GAS_CONST * (temperature_celsius + CONSTANTS_ABSOLUTE_NULL_KELVIN)); } diff --git a/apps/systemlib/conversions.h b/apps/systemlib/conversions.h index 4db6de772..c2987709b 100644 --- a/apps/systemlib/conversions.h +++ b/apps/systemlib/conversions.h @@ -44,7 +44,10 @@ #include <float.h> #include <stdint.h> -#define CONSTANTS_ONE_G 9.80665f +#define CONSTANTS_ONE_G 9.80665f +#define CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C 1.225f +#define CONSTANTS_AIR_GAS_CONST 8.31432f +#define CONSTANTS_ABSOLUTE_NULL_KELVIN 273.15f __BEGIN_DECLS |