ardupilot/libraries/AP_Baro/AP_Baro_HIL.cpp

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/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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#include "AP_Baro.h"
#include <AP_HAL/AP_HAL.h>
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extern const AP_HAL::HAL& hal;
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AP_Baro_HIL::AP_Baro_HIL(AP_Baro &baro) :
AP_Baro_Backend(baro)
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{
_instance = _frontend.register_sensor();
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}
// ==========================================================================
// based on tables.cpp from http://www.pdas.com/atmosdownload.html
/*
Compute the temperature, density, and pressure in the standard atmosphere
Correct to 20 km. Only approximate thereafter.
*/
void AP_Baro::SimpleAtmosphere(
const float alt, // geometric altitude, km.
float& sigma, // density/sea-level standard density
float& delta, // pressure/sea-level standard pressure
float& theta) // temperature/sea-level standard temperature
{
const float REARTH = 6369.0f; // radius of the Earth (km)
const float GMR = 34.163195f; // gas constant
float h=alt*REARTH/(alt+REARTH); // geometric to geopotential altitude
if (h < 11.0f) {
// Troposphere
theta=(288.15f-6.5f*h)/288.15f;
delta=powf(theta, GMR/6.5f);
} else {
// Stratosphere
theta=216.65f/288.15f;
delta=0.2233611f*expf(-GMR*(h-11.0f)/216.65f);
}
sigma = delta/theta;
}
/*
convert an altitude in meters above sea level to a presssure and temperature
*/
void AP_Baro::setHIL(float altitude_msl)
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{
float sigma, delta, theta;
const float p0 = 101325;
SimpleAtmosphere(altitude_msl*0.001f, sigma, delta, theta);
float p = p0 * delta;
float T = 303.16f * theta - 273.16f; // Assume 30 degrees at sea level - converted to degrees Kelvin
setHIL(0, p, T);
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}
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/*
set HIL pressure and temperature for an instance
*/
void AP_Baro::setHIL(uint8_t instance, float pressure, float temperature)
{
if (instance >= _num_sensors) {
// invalid
return;
}
sensors[instance].pressure = pressure;
sensors[instance].temperature = temperature;
sensors[instance].last_update_ms = hal.scheduler->millis();
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}