From 2c2c65d446f991b273ee1f275fd2bc8440f74844 Mon Sep 17 00:00:00 2001 From: Thomas Gubler Date: Fri, 22 Feb 2013 22:26:04 +0100 Subject: [PATCH] corrected some wrong units (used in airspeed calculation) --- apps/systemlib/conversions.c | 2 +- apps/systemlib/conversions.h | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/apps/systemlib/conversions.c b/apps/systemlib/conversions.c index 2b8003e4582..ac94252c572 100644 --- a/apps/systemlib/conversions.c +++ b/apps/systemlib/conversions.c @@ -150,5 +150,5 @@ void quat2rot(const float Q[4], float R[9]) float get_air_density(float static_pressure, float temperature_celsius) { - return static_pressure / (CONSTANTS_AIR_GAS_CONST * (temperature_celsius + CONSTANTS_ABSOLUTE_NULL_KELVIN)); + return static_pressure / (CONSTANTS_AIR_GAS_CONST * (temperature_celsius - CONSTANTS_ABSOLUTE_NULL_CELSIUS)); } diff --git a/apps/systemlib/conversions.h b/apps/systemlib/conversions.h index c2987709bba..5d485b01f39 100644 --- a/apps/systemlib/conversions.h +++ b/apps/systemlib/conversions.h @@ -44,10 +44,10 @@ #include #include -#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 +#define CONSTANTS_ONE_G 9.80665f // m/s^2 +#define CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C 1.225f // kg/m^3 +#define CONSTANTS_AIR_GAS_CONST 287.1f // J/(kg * K) +#define CONSTANTS_ABSOLUTE_NULL_CELSIUS -273.15f // °C __BEGIN_DECLS