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AP_Baro: use ground_temperature instead of calibration_temperature for alt calculation

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ziltoid2 2015-05-16 21:49:36 +03:00 committed by Andrew Tridgell
parent 92c4c5cbcf
commit 23787cf695
1 changed files with 2 additions and 3 deletions
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libraries/AP_Baro/AP_Baro.cpp
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@ -173,16 +173,15 @@ void AP_Baro::update_calibration()
float AP_Baro::get_altitude_difference(float base_pressure, float pressure) const
{
float ret;
float temp = get_ground_temperature() + 273.15f;
#if HAL_CPU_CLASS <= HAL_CPU_CLASS_16
// on slower CPUs use a less exact, but faster, calculation
float scaling = base_pressure / pressure;
float temp = get_calibration_temperature() + 273.15f;
ret = logf(scaling) * temp * 29.271267f;
#else
// on faster CPUs use a more exact calculation
float scaling = pressure / base_pressure;
float temp = get_calibration_temperature() + 273.15f;
// This is an exact calculation that is within +-2.5m of the standard atmosphere tables
// in the troposphere (up to 11,000 m amsl).
ret = 153.8462f * temp * (1.0f - expf(0.190259f * logf(scaling)));