void
AirspaceAltitude::SetFlightLevel(const AtmosphericPressure &press)
{
static constexpr fixed fl_feet_to_m(30.48);
if (reference == AltitudeReference::STD)
altitude = press.PressureAltitudeToQNHAltitude(flight_level * fl_feet_to_m);
}
static bool
test_qnh_round()
{
AtmosphericPressure sp = AtmosphericPressure::Standard().QNHAltitudeToStaticPressure(fixed(100));
AtmosphericPressure pres =
AtmosphericPressure::FindQNHFromPressure(sp, fixed(120));
fixed h0 = pres.PressureAltitudeToQNHAltitude(fixed(100));
if (verbose) {
printf("%g\n",FIXED_DOUBLE(h0));
}
return fabs(h0-fixed(120))<fixed(1);
}
static void
ComputePressure(NMEAInfo &basic, const AtmosphericPressure qnh)
{
const bool qnh_available = qnh.IsPlausible();
const bool static_pressure_available = basic.static_pressure_available;
const bool pressure_altitude_available = basic.pressure_altitude_available;
if (!static_pressure_available) {
if (pressure_altitude_available) {
basic.static_pressure =
AtmosphericPressure::PressureAltitudeToStaticPressure(basic.pressure_altitude);
basic.static_pressure_available = basic.pressure_altitude_available;
} else if (basic.baro_altitude_available && qnh_available) {
basic.static_pressure =
qnh.QNHAltitudeToStaticPressure(basic.baro_altitude);
basic.static_pressure_available = basic.baro_altitude_available;
}
}
if (!pressure_altitude_available) {
if (static_pressure_available) {
basic.pressure_altitude =
AtmosphericPressure::StaticPressureToPressureAltitude(basic.static_pressure);
basic.pressure_altitude_available = basic.static_pressure_available;
} else if (basic.baro_altitude_available && qnh_available) {
basic.pressure_altitude =
qnh.QNHAltitudeToPressureAltitude(basic.baro_altitude);
basic.pressure_altitude_available = basic.baro_altitude_available;
}
}
if (qnh_available) {
/* if the current pressure and the QNH is known, then true baro
altitude should be discarded, because the external device which
provided it may have a different QNH setting */
if (static_pressure_available) {
basic.baro_altitude =
qnh.StaticPressureToQNHAltitude(basic.static_pressure);
basic.baro_altitude_available = basic.static_pressure_available;
} else if (pressure_altitude_available) {
basic.baro_altitude =
qnh.PressureAltitudeToQNHAltitude(basic.pressure_altitude);
basic.baro_altitude_available = basic.pressure_altitude_available;
}
} else if (!basic.baro_altitude_available && pressure_altitude_available)
/* no QNH, but let's fill in the best fallback value we can get,
without setting BaroAltitudeAvailable */
basic.baro_altitude = basic.pressure_altitude;
}