Beispiel #1
0
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);
}
Beispiel #2
0
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);
}
Beispiel #3
0
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;
}