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  • Author or Editor: R. L. Vaughan x
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Alfred R. Rodi
,
James C. Fankhauser
, and
Robin L. Vaughan

Abstract

Aircraft distance-measuring-equipment (DME) data are used to update position, velocity, and wind measurements from inertial navigation systems (INS) measurements. Data from conventional single-channel DME sets, suitably calibrated, are shown to be adequate to resolve the Schuler oscillation and correct INS positions to better than 1-km accuracy. The satellite-based NAVSTAR global position system (GPS) is rapidly superseding other systems for external position reference. However, DME is reliable and very accurate and has been recorded on many research datasets. The principal limitation of the DME is that it is restricted to land-based navigation. The regression technique used does not necessitate multiple DME receivers or station switching and involves few restrictions on the collection of the data. However, the results improve when more than one station is used. Comparisons with other navigation systems (interferometer and loran) demonstrate the method's skill in resolving INS errors. Intercomparisons among several research aircraft flying in close formation support the method's usefulness in correcting biases in INS data.

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R. J. Keeler
,
R. J. Serafin
,
R. L. Schwiesow
,
D. H. Lenschow
,
J. M. Vaughan
, and
A. A. Woodfield

Abstract

Measurement of air motion relative to an aircraft by a conically scanned optical Doppler technique has advantages over measurements with conventional gust probes for many applications. Advantages of the laser air motion sensing technique described here include calibration based on physical constants rather than experiment for an accurate measurement of mean wind, freedom from flow distortion effects on turbulence measurements, all-weather performance, reduction in error from mechanical vibrations and ability to measure vertical wind shear. An experiment comparing a single-component laser velocimeter and a differential pressure gust probe shows that the optical approach measures the turbulence spectrum accurately at frequencies up to 10 Hz and that the signal-to-noise ratio is not a limiting factor. In addition, we have observed the effect of spectral skewing caused by airflow distortion in cloud.

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J. C. Fankhauser
,
C. J. Biter
,
C. G. Mohr
, and
R. L. Vaughan

Abstract

Objective numerical techniques are applied in analyzing constant altitude aircraft measurements obtained from coordinated research flights in thunderstorm inflow regions. The approach combines meteorological and flight track data from dual or single aircraft missions in a common frame of reference and transforms the observations from original analogue format to horizontal two-dimensional Cartesian coordinates. Operational procedures guiding the data collection, intercomparison techniques for refining instrument calibrations and corrections for aircraft navigation errors are all considered.

Results of the interpolations are judged in the context of the storms' associated radar echo features. Primary applications include calculation of water vapor influx in cloud base updrafts. Evidence indicates that the fullest exploitation of the inflow mapping will come through combining kinematic fields observed concurrently by aircraft and multiple Doppler radars.

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