AP_Baro: Barometric Altitude and Pressure Library

// Called once at startup (with save=true to persist ground pressure)
AP::baro().calibrate(true);

// Convert a pressure reading to an altitude (m AMSL)
float alt = AP::baro().get_altitude_from_pressure(pressure_pa);

// Equivalent airspeed to true airspeed scale factor
float eas2tas = AP::baro()._get_EAS2TAS();

#include <AP_Baro/AP_Baro.h>

void example_baro_read()
{
    AP_Baro &baro = AP::baro();

    // Always check health before using data
    if (!baro.healthy()) {
        return;
    }

    // Relative altitude above takeoff point (metres)
    float alt_m = baro.get_altitude();

    // Raw pressure in Pascals
    float pressure_pa = baro.get_pressure();

    // Sensor temperature in °C
    float temp_c = baro.get_temperature();

    // Vertical climb rate (m/s, positive = climbing)
    float climb = baro.get_climb_rate();

    // Iterate over all registered barometers
    for (uint8_t i = 0; i < baro.num_instances(); i++) {
        if (baro.healthy(i)) {
            float alt_i = baro.get_altitude(i);
        }
    }
}

// Force instance 1 as primary
AP::baro().set_primary_baro(1);

// Read primary instance index
uint8_t primary = AP::baro().get_primary();