ACTS
Propagation Experiment: Experiment Design, Calibration,
and Data Preparation and Archival
Robert
K. Crane, Fellow, IEEE, Xuhe Wang, D. B. Westenhaver, and
Wolfhard J. Vogel, Fellow, IEEE
Abstract
The
National Aeronautics and Space Administration Advanced Communications
Technology Satellite (ACTS) propagation experiment was designed
to obtain slant-path attenuation statistics for locations
within the United States and Canada for use in the design
of low-margin Ka-band satellite communication systems. Experimenters
at seven different locations have collected propagation
data for more than two years. The propagation terminals
used for the experiment were identical. A single preprocessing
program was used by the experimenters to provide for automatic
calibration, generation of attenuation histograms, and data
archival. In this paper, the calibration procedures are
described and estimates given for measurement accuracy.
ACTS
provided beacons at 20.2 and 27.5 GHz for use in making
attenuation measurements. In addition to the beacon receivers,
each ACTS propagation terminal has two total power radiometers
with center frequencies at the beacon frequencies. The radiometers
are used to establish the beacon signal reference levels
needed for calculating beacon attenuation values. For the
combined radiometer and beacon measurement system, the attenuation
measurement error was less than a maximum of 1.0 dB and
was generally less than 0.3 dB. The dynamic range for attenuation
measurement varied from site to site depending on location
relative to the peak of the satellite beacon antenna pattern.
For locations within the continental United States, the
dynamic range was better than 20 dB.
Keywords:
Attenuation, attenuation measurement, microwave radio propagation
meteorological factors, microwave radiometry, millimeter
wave communication, millimeter wave radio propagation meteorological
factors, rain, satellite communication.
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