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Diffstat (limited to 'apps/systemlib/airspeed.c')
| -rw-r--r-- | apps/systemlib/airspeed.c | 111 |
1 files changed, 0 insertions, 111 deletions
diff --git a/apps/systemlib/airspeed.c b/apps/systemlib/airspeed.c deleted file mode 100644 index 264287b10..000000000 --- a/apps/systemlib/airspeed.c +++ /dev/null @@ -1,111 +0,0 @@ -/**************************************************************************** - * - * Copyright (C) 2012-2013 PX4 Development Team. All rights reserved. - * Author: Lorenz Meier <lm@inf.ethz.ch> - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * 3. Neither the name PX4 nor the names of its contributors may be - * used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS - * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE - * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, - * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS - * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED - * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN - * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE - * POSSIBILITY OF SUCH DAMAGE. - * - ****************************************************************************/ - -/** - * @file airspeed.c - * Airspeed estimation - * - * @author Lorenz Meier <lm@inf.ethz.ch> - * - */ - -#include <stdio.h> -#include <math.h> -#include "conversions.h" -#include "airspeed.h" - - -/** - * Calculate indicated airspeed. - * - * Note that the indicated airspeed is not the true airspeed because it - * lacks the air density compensation. Use the calc_true_airspeed functions to get - * the true airspeed. - * - * @param differential_pressure total_ pressure - static pressure - * @return indicated airspeed in m/s - */ -float calc_indicated_airspeed(float differential_pressure) -{ - - if (differential_pressure > 0) { - return sqrtf((2.0f*differential_pressure) / CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C); - } else { - return -sqrtf((2.0f*fabs(differential_pressure)) / CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C); - } - -} - -/** - * Calculate true airspeed from indicated airspeed. - * - * Note that the true airspeed is NOT the groundspeed, because of the effects of wind - * - * @param speed_indicated current indicated airspeed - * @param pressure_ambient pressure at the side of the tube/airplane - * @param temperature_celsius air temperature in degrees celcius - * @return true airspeed in m/s - */ -float calc_true_airspeed_from_indicated(float speed_indicated, float pressure_ambient, float temperature_celsius) -{ - return speed_indicated * sqrtf(CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C / get_air_density(pressure_ambient, temperature_celsius)); -} - -/** - * Directly calculate true airspeed - * - * Note that the true airspeed is NOT the groundspeed, because of the effects of wind - * - * @param total_pressure pressure inside the pitot/prandtl tube - * @param static_pressure pressure at the side of the tube/airplane - * @param temperature_celsius air temperature in degrees celcius - * @return true airspeed in m/s - */ -float calc_true_airspeed(float total_pressure, float static_pressure, float temperature_celsius) -{ - float density = get_air_density(static_pressure, temperature_celsius); - if (density < 0.0001f || !isfinite(density)) { - density = CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C; - printf("[airspeed] Invalid air density, using density at sea level\n"); - } - - float pressure_difference = total_pressure - static_pressure; - - if(pressure_difference > 0) { - return sqrtf((2.0f*(pressure_difference)) / density); - } else - { - return -sqrtf((2.0f*fabs(pressure_difference)) / density); - } -} |