Reviewing Wind Measurement Approaches for Fixed-Wing Unmanned Aircraft

Rautenberg, Alexander; Graf, Martin S.; Wildmann, Norman; Platis, Andreas; Bange, Jens

doi:10.3390/atmos9110422

Cited by 47 publications

(45 citation statements)

References 43 publications

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“…The offset ∆Φ for the roll angle is set to zero and can be, according to Van den Kroonenberg et al [7], neglected, since the influence on the wind components is very small. The offsets ∆Ψ and ∆Θ are applied to the transformation T gb in Equation (5) and the factor f tas is multiplied with the norm of the true airspeed vector | u a | in Equation (4). To ensure comparability between the three calibrations, the correction offsets and factors are determined in the exact same way.…”

Section: In-flight Calibration Of the Wind Measurementmentioning

confidence: 99%

“…For environmental science in the atmospheric boundary layer (ABL), airborne measurements supplement the limited coverage of ground-based measurements or tethered balloons. Manned research aircraft have intensively investigated a wide range of processes and phenomena [1][2][3] and unmanned aerial systems (UAS) adopted the measurement techniques of quantities such as temperature, humidity, and the wind vector [4][5][6][7], but are not limited to these, as shown by Bärfuss et al [8] for aerosol and radiation measurements, or by Schuyler and Guzman [9] for gas concentrations. The 3D wind vector using multi-hole probes is calculated by the summation of the ground speed vector of the vehicle and the true airspeed vector.…”

Section: Introductionmentioning

confidence: 99%

“…Another important motivation for this study is the question of whether the cruising airspeed of the Multi-Purpose Airborne Sensor Carrier (MASC) can be freely chosen for the wind measurement or if further calibration in the wind tunnel is required to gain this flexibility. For atmospheric research, boundary-layer meteorology, and wind-energy studies, the environment-physics group at the Center for Applied Geoscience (ZAG), University of Tübingen, Germany, designed and built MASC [4,6]. The airspeed of MASC can be set between 15 and 30 m s −1 , depending on the payload and the targeted flight time or battery load, making it versatile for different scenarios.…”

Section: Introductionmentioning

confidence: 99%

“…For turbulence statistics, flux calculations, and quantitative analysis of turbine wake characteristics, an independent measurement of the true airspeed with a pitot tube and the interpolation of calibration polynomials at different Reynolds numbers of the probe's tip onto the Reynolds number during the measurement, reducing the uncertainty significantly.Atmosphere 2019, 10, 124 2 of 33 attitude, position, and velocity of the vehicle, measured by an inertial navigation system (INS), multiple coordinate transformations finally yield the wind vector. This method is widely used in manned aircraft [1,10] and on fixed-wing UAS [4][5][6][7]. The accuracy of the wind vector measurement is crucial, and the propagation of errors have many influencing factors, originating in the attitude and ground speed measurement of the aircraft, the flow angles and flow magnitude (true airspeed vector) measurement with the multi-hole probe, and also in the measurement of the thermodynamic state of the air.…”

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confidence: 99%

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Calibration Procedure and Accuracy of Wind and Turbulence Measurements with Five-Hole Probes on Fixed-Wing Unmanned Aircraft in the Atmospheric Boundary Layer and Wind Turbine Wakes

et al. 2019

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For research in the atmospheric boundary layer and in the vicinity of wind turbines, the turbulent 3D wind vector can be measured from fixed-wing unmanned aerial systems (UAS) with a five-hole probe and an inertial navigation system. Since non-zero vertical wind and varying horizontal wind causes variations in the airspeed of the UAS, and since it is desirable to sample with a flexible cruising airspeed to match a broad range of operational requirements, the influence of airspeed variations on mean values and turbulence statistics is investigated. Three calibrations of the five-hole probe at three different airspeeds are applied to the data of three flight experiments. Mean values and statistical moments of second order, calculated from horizontal straight level flights are compared between flights in a stably stratified polar boundary layer and flights over complex terrain in high turbulence. Mean values are robust against airspeed variations, but the turbulent kinetic energy, variances and especially covariances, and the integral length scale are strongly influenced. Furthermore, a transect through the wake of a wind turbine and a tip vortex is analyzed, showing the instantaneous influence of the intense variations of the airspeed on the measurement of the turbulent 3D wind vector. For turbulence statistics, flux calculations, and quantitative analysis of turbine wake characteristics, an independent measurement of the true airspeed with a pitot tube and the interpolation of calibration polynomials at different Reynolds numbers of the probe's tip onto the Reynolds number during the measurement, reducing the uncertainty significantly.Atmosphere 2019, 10, 124 2 of 33 attitude, position, and velocity of the vehicle, measured by an inertial navigation system (INS), multiple coordinate transformations finally yield the wind vector. This method is widely used in manned aircraft [1,10] and on fixed-wing UAS [4][5][6][7]. The accuracy of the wind vector measurement is crucial, and the propagation of errors have many influencing factors, originating in the attitude and ground speed measurement of the aircraft, the flow angles and flow magnitude (true airspeed vector) measurement with the multi-hole probe, and also in the measurement of the thermodynamic state of the air. Extensive studies for various systems and subsystems of the wind vector measurement with manned research aircraft [11][12][13][14][15][16], including in-flight calibration procedures and uncertainty analysis [10,17], and with UAS (e.g., for the M 2 AV [7]) were performed.So far, for UAS, calibration maneuvers during flight and the influence of airspeed variations on the wind vector measurement were not addressed in terms of calibration and uncertainty analysis for the 3D wind vector measurement with multi-hole probes. Since a misalignment between the multi-hole probe's orientation and the aircraft cannot be avoided, an in-flight calibration must be applied [16]. Calibration maneuvers during flight such as the "acceleration-deceleration maneuver", the "ya...

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Section: In-flight Calibration Of the Wind Measurementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Calibration Procedure and Accuracy of Wind and Turbulence Measurements with Five-Hole Probes on Fixed-Wing Unmanned Aircraft in the Atmospheric Boundary Layer and Wind Turbine Wakes

et al. 2019

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“…A number of previous studies have measured boundary layer winds and turbulent parameters using UAV sampling [59][60][61]. Barbieri et al.…”

Section: Introductionmentioning

confidence: 99%

A Near-Field Gaussian Plume Inversion Flux Quantification Method, Applied to Unmanned Aerial Vehicle Sampling

et al. 2019

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The accurate quantification of methane emissions from point sources is required to better quantify emissions for sector-specific reporting and inventory validation. An unmanned aerial vehicle (UAV) serves as a platform to sample plumes near to source. This paper describes a near-field Gaussian plume inversion (NGI) flux technique, adapted for downwind sampling of turbulent plumes, by fitting a plume model to measured flux density in three spatial dimensions. The method was refined and tested using sample data acquired from eight UAV flights, which measured a controlled release of methane gas. Sampling was conducted to a maximum height of 31 m (i.e. above the maximum height of the emission plumes). The method applies a flux inversion to plumes sampled near point sources. To test the method, a series of random walk sampling simulations were used to derive an NGI upper uncertainty bound by quantifying systematic flux bias due to a limited spatial sampling extent typical for short-duration small UAV flights (less than 30 min). The development of the NGI method enables its future use to quantify methane emissions for point sources, facilitating future assessments of emissions from specific source-types and source areas. This allows for atmospheric measurement-based fluxes to be derived using downwind UAV sampling for relatively rapid flux analysis, without the need for access to difficult-to-reach areas.

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Wind observations from hot‐air balloons and the application in an NWP model

Bruijn

Bosveld

Haan

et al. 2023

Meteorological Applications

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In this paper, we report on a wind observation method based on the movement of hot‐air balloons (HABs). A quality assessment was carried out by comparing against wind observations at the meteorological tower of Cabauw in the Netherlands during May–September 2018, and the obtained standard deviations in error were and for the measured zonal and meridional wind components, respectively. Subsequent comparison against short‐term forecasts of the HARMONIE‐AROME model showed a standard deviation of 2.5 ms−1 for the wind vector difference. From the HAB observation set, a case was selected with a rapidly changing wind field belonging to a small intensifying depression. The HAB wind observation was applied in data assimilation as a proof of principle for a single‐observation experiment. It is shown that in a complex baroclinic situation, the model state is slightly improved.

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Reviewing Wind Measurement Approaches for Fixed-Wing Unmanned Aircraft

Cited by 47 publications

References 43 publications

Calibration Procedure and Accuracy of Wind and Turbulence Measurements with Five-Hole Probes on Fixed-Wing Unmanned Aircraft in the Atmospheric Boundary Layer and Wind Turbine Wakes

Calibration Procedure and Accuracy of Wind and Turbulence Measurements with Five-Hole Probes on Fixed-Wing Unmanned Aircraft in the Atmospheric Boundary Layer and Wind Turbine Wakes

A Near-Field Gaussian Plume Inversion Flux Quantification Method, Applied to Unmanned Aerial Vehicle Sampling

Wind observations from hot‐air balloons and the application in an NWP model

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