mirror of
https://bitbucket.org/librepilot/librepilot.git
synced 2025-01-19 04:52:12 +01:00
96 lines
3.6 KiB
C
96 lines
3.6 KiB
C
/**
|
|
******************************************************************************
|
|
* @addtogroup OpenPilotModules OpenPilot Modules
|
|
* @{
|
|
* @addtogroup AirspeedModule Airspeed Module
|
|
* @brief Communicate with airspeed sensors and return values
|
|
* @{
|
|
*
|
|
* @file baro_airspeed.c
|
|
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
|
|
* @brief Airspeed module, handles temperature and pressure readings from BMP085
|
|
*
|
|
* @see The GNU Public License (GPL) Version 3
|
|
*
|
|
*****************************************************************************/
|
|
/*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
/**
|
|
* Output object: BaroAirspeed
|
|
*
|
|
* This module will periodically update the value of the BaroAirspeed object.
|
|
*
|
|
*/
|
|
|
|
#include "openpilot.h"
|
|
#include "hwsettings.h"
|
|
#include "airspeedsettings.h"
|
|
#include "airspeedsensor.h" // object that will be updated by the module
|
|
#include "airspeedalarm.h"
|
|
|
|
#if defined(PIOS_INCLUDE_SDP3X)
|
|
|
|
#define CALIBRATION_IDLE_MS 2000 // Time to wait before calibrating, in [ms]
|
|
#define CALIBRATION_COUNT_MS 2000 // Time to spend calibrating, in [ms]
|
|
|
|
#define P0 101325.0f // standard pressure
|
|
#define CCEXPONENT 0.2857142857f // exponent of compressibility correction 2/7
|
|
#define CASFACTOR 760.8802669f // sqrt(5) * speed of sound at standard
|
|
#define TASFACTOR 0.05891022589f // 1/sqrt(T0)
|
|
|
|
// Private types
|
|
|
|
// Private variables
|
|
|
|
// Private functions
|
|
|
|
static volatile struct PIOS_SDP3X_STATE state = { .status = SDP3X_STATUS_NOTFOUND, .pressure = 0, .temperature = 0 };
|
|
|
|
void baro_airspeedGetSDP3X(AirspeedSensorData *airspeedSensor, AirspeedSettingsData *airspeedSettings)
|
|
{
|
|
// Check to see if airspeed sensor is returning airspeedSensor
|
|
PIOS_SDP3X_ReadAirspeed(&state);
|
|
airspeedSensor->SensorValue = state.pressure;
|
|
airspeedSensor->SensorValueTemperature = state.temperature;
|
|
|
|
if (state.status != SDP3X_STATUS_READY) {
|
|
airspeedSensor->SensorConnected = AIRSPEEDSENSOR_SENSORCONNECTED_FALSE;
|
|
airspeedSensor->CalibratedAirspeed = 0;
|
|
AirspeedAlarm(SYSTEMALARMS_ALARM_ERROR);
|
|
return;
|
|
}
|
|
|
|
// No calibration, sensor comes factory calibrated!
|
|
|
|
// Compute airspeed
|
|
airspeedSensor->Temperature = ((float)state.temperature / 200.0f) + 273.15f; // convert to kelvin
|
|
airspeedSensor->DifferentialPressure = (1.0f / (((float)state.scale) + 1e-9f)) * ((float)(state.pressure) - (float)((int16_t)(airspeedSettings->ZeroPoint)));
|
|
airspeedSensor->CalibratedAirspeed = airspeedSettings->Scale * CASFACTOR * sqrtf(powf(fabsf(airspeedSensor->DifferentialPressure) / P0 + 1.0f, CCEXPONENT) - 1.0f);
|
|
airspeedSensor->TrueAirspeed = airspeedSensor->CalibratedAirspeed * TASFACTOR * sqrtf(airspeedSensor->Temperature);
|
|
|
|
airspeedSensor->SensorConnected = AIRSPEEDSENSOR_SENSORCONNECTED_TRUE;
|
|
AirspeedAlarm(SYSTEMALARMS_ALARM_OK);
|
|
}
|
|
|
|
|
|
#endif /* if defined(PIOS_INCLUDE_SDP3X) */
|
|
|
|
/**
|
|
* @}
|
|
* @}
|
|
*/
|