ardupilot/libraries/AP_Baro/AP_Baro_HIL.cpp

91 lines
2.5 KiB
C++

#include "AP_Baro_HIL.h"
#include <AP_HAL/AP_HAL.h>
extern const AP_HAL::HAL& hal;
AP_Baro_HIL::AP_Baro_HIL(AP_Baro &baro) :
AP_Baro_Backend(baro)
{
_instance = _frontend.register_sensor();
}
// ==========================================================================
// 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)
{
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
_hil.pressure = p;
_hil.temperature = T;
_hil.updated = true;
}
/*
set HIL pressure and temperature for an instance
*/
void AP_Baro::setHIL(uint8_t instance, float pressure, float temperature, float altitude, float climb_rate, uint32_t last_update_ms)
{
if (instance >= _num_sensors) {
// invalid
return;
}
_hil.pressure = pressure;
_hil.temperature = temperature;
_hil.altitude = altitude;
_hil.climb_rate = climb_rate;
_hil.updated = true;
_hil.have_alt = true;
if (last_update_ms != 0) {
_hil.last_update_ms = last_update_ms;
_hil.have_last_update = true;
}
}
// Read the sensor
void AP_Baro_HIL::update(void)
{
if (_frontend._hil.updated) {
_frontend._hil.updated = false;
_copy_to_frontend(0, _frontend._hil.pressure, _frontend._hil.temperature);
}
}