mirror of https://github.com/ArduPilot/ardupilot
100 lines
2.7 KiB
C++
100 lines
2.7 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_Baro_HIL.h"
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#include <AP_HAL.h>
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extern const AP_HAL::HAL& hal;
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// Public Methods //////////////////////////////////////////////////////////////
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bool AP_Baro_HIL::init()
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{
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_flags.healthy = false;
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return true;
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}
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// Read the sensor. This is a state machine
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// We read one time Temperature (state = 1) and then 4 times Pressure (states 2-5)
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uint8_t AP_Baro_HIL::read()
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{
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uint8_t result = 0;
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if (_count != 0) {
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hal.scheduler->suspend_timer_procs();
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result = 1;
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Press = _pressure_sum / _count;
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Temp = _temperature_sum / _count;
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_pressure_samples = _count;
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_count = 0;
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_pressure_sum = 0;
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_temperature_sum = 0;
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hal.scheduler->resume_timer_procs();
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}
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return result;
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}
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void AP_Baro_HIL::setHIL(float pressure, float temperature)
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{
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if (pressure > 0) {
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_count = 1;
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_pressure_sum = pressure;
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_temperature_sum = temperature;
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_last_update = hal.scheduler->millis();
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_flags.healthy = true;
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}
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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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static void 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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}
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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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void AP_Baro_HIL::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(p, T);
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}
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float AP_Baro_HIL::get_pressure() {
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return Press;
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}
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float AP_Baro_HIL::get_temperature() {
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return Temp;
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}
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