/****************************************************************************
 *
 *   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,
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 *
 ****************************************************************************/

/**
 * @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"

 __BEGIN_DECLS
 
 /**
  * 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 total_pressure pressure inside the pitot/prandtl tube
  * @param static_pressure pressure at the side of the tube/airplane
  * @return indicated airspeed in m/s
  */
 __EXPORT float calc_indicated_airspeed(float differential_pressure);
 
 /**
  * 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
  */
 __EXPORT float calc_true_airspeed_from_indicated(float speed_indicated, float pressure_ambient, float 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
  */
 __EXPORT float calc_true_airspeed(float total_pressure, float static_pressure, float temperature_celsius);

 /**
 * Calculates air density.
 *
 * @param static_pressure ambient pressure in millibar
 * @param temperature_celcius air / ambient temperature in celcius
 */
__EXPORT float get_air_density(float static_pressure, float temperature_celsius);

__END_DECLS

#endif