Calibrating airborne measurements of airspeed, pressure and temperature using a Doppler laser air-motion sensor

Abstract

Abstract.A new laser air-motion sensor measures the true airspeed with a standard uncertainty of less than 0.1 m s −1 and so reduces uncertainty in the measured component of the relative wind along the longitudinal axis of the aircraft to about the same level. The calculated pressure expected from that airspeed at the inlet of a pitot tube then provides a basis for calibrating the measurements of dynamic and static pressure, reducing standard uncertainty in those measurements to less than 0.3 hPa and the precision applicable to steady flight conditions to about 0.1 hPa. These improved measurements of pressure, combined with high-resolution measurements of geometric altitude from the global positioning system, then indicate (via integrations of the hydrostatic equation during climbs and descents) that the offset and uncertainty in temperature measurement for one research aircraft are +0.3 ± 0.3 • C. For airspeed, pressure and temperature, these are significant reductions in uncertainty vs. those obtained from calibrations using standard techniques. Finally, it is shown that although the initial calibration of the measured static and dynamic pressures requires a measured temperature, once calibrated these measured pressures and the measurement of airspeed from the new laser air-motion sensor provide a measurement of temperature that does not depend on any other temperature sensor.

Drone-based meteorological observations up to the tropopause – a concept study

“…Whereas crewed research aircraft typically perform welldescribed calibration and validation manoeuvres (Haering, 1990;Drüe et al, 2008;Bange et al, 2013;Cooper et al, 2014;Mallaun et al, 2015;Hartmann et al, 2018), which can also be applied to drone systems, the following techniques freely adopted from Bärfuss et al (2018) were used within this study to determine correction parameters:…”

The Horizontal Spectrum of Vertical Velocities near the Tropopause from Global to Gravity Wave Scales

“…Accurate wind measurements are demanding in particular for fast-flying jets because the wind vector is the relatively small difference between the measured velocity vector of the aircraft with respect to Earth and the measured velocity vector of the air with respect to the aircraft (Lenschow 1986). The measurements combine position and attitude data from inertial navigation platforms and satellite navigation systems, and air velocity and angleof-attack data from static and dynamic pressure and temperature sensors at the aircraft fuselage and nose (Cooper et al 2014;Mallaun et al 2015;Giez et al 2017). These techniques allow to derive spectra of vertical energy and momentum fluxes in mountain gravity waves (Smith et al 2016).…”

Stratospheric Gravity Wave Fluxes and Scales during DEEPWAVE

“…The DEEPWAVE GV gravity wave surveys benefited from recent improved calibrations of aircraft wind and pressure sensors (Cooper et al 2014). We also had redundant sensors for wind, pressure, and geometric altitude.…”

“…These improvements were accomplished in part with the use of a Doppler laser air motion sensor that could detect the aircraft airspeed more accurately than the conventional pitot-static pressure method (Cooper et al 2014). While this lidar was not used in .…”

“…The correlations and linear regression slopes between the primary and secondary sensor pairs are shown in Table 2. The secondary static pressure (PS_A) is an aircraft system signal with some smoothing (Cooper et al 2014). The wind variables with suffix ''_GP'' come from the left underwing pod instead of the nose-cone gust probe.…”