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