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| Titel |
Measuring the 3-D wind vector with a weight-shift microlight aircraft |
| VerfasserIn |
S. Metzger, W. Junkermann, K. Butterbach-Bahl, H. P. Schmid, T. Foken |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 4, no. 7 ; Nr. 4, no. 7 (2011-07-19), S.1421-1444 |
| Datensatznummer |
250002054
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| Publikation (Nr.) |
 copernicus.org/amt-4-1421-2011.pdf |
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| Zusammenfassung |
| This study investigates whether the 3-D wind vector can be measured
reliably from a highly transportable and low-cost weight-shift
microlight aircraft. Therefore we draw up a transferable procedure to
accommodate flow distortion originating from the aircraft body and -wing.
This procedure consists of the analysis of aircraft dynamics
and seven successive calibration steps. For our aircraft the
horizontal wind components receive their greatest single amendment
(14 %, relative to the initial uncertainty) from the correction of
flow distortion magnitude in the dynamic pressure
computation. Conversely the vertical wind component is most of all
improved (31 %) by subsequent steps considering the 3-D flow
distortion distribution in the flow angle computations. Therein the
influences of the aircraft's trim (53 %), as well as
changes in the aircraft lift (16 %) are considered by using the
measured lift coefficient as explanatory variable. Three independent
lines of analysis are used to evaluate the quality of the wind
measurement: (a) A wind tunnel study in combination with the
propagation of sensor uncertainties defines the systems input
uncertainty to ≈0.6 m s−1 at the extremes of a 95 %
confidence interval. (b) During severe vertical flight manoeuvres the
deviation range of the vertical wind component does not exceed
0.3 m s−1. (c) The comparison with ground based wind
measurements yields an overall operational uncertainty (root mean
square error) of ≈0.4 m s−1 for the horizontal and
≈0.3 m s−1 for the vertical wind components. No
conclusive dependence of the uncertainty on the wind magnitude
(<8 m s−1) or true airspeed (ranging from
23–30 m s−1) is found. Hence our analysis provides the
necessary basis to study the wind measurement precision and spectral
quality, which is prerequisite for reliable Eddy-Covariance flux
measurements. |
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