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Viking Orbiter 75 in-flight pointing calibration of the high-gain antennaAn in-flight pointing calibration technique developed for the Viking Orbiter high-gain antenna has been validated through actual flight usage. The desired telecommunications performance dictated that the high-gain antenna pointing error be held at 0.7 deg, which would have been exceeded without calibration. The in-flight calibration methodology required the development of a stochastic model of the spacecraft rotational biases and earth-received signal strength measurements. The signal strength measurements, which were performed at X-band frequency, were used as observations to estimate the rotational biases and their corresponding uncertainties. Reducing the uncertainties of these parameters resulted in increased antenna pointing accuracy. The initial pointing offset was estimated to be in excess of 1 deg, and after in-flight calibration it was reduced to about 0.66 deg. About 50% of the original offset could not be calibrated, thus the improvement on the remaining offset is better than 50%.
Document ID
19800063553
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Assefi, T.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Alexander, J. W.
(California Institute of Technology, Jet Propulsion Laboratory, Pasadena Calif., United States)
Date Acquired
August 10, 2013
Publication Date
October 1, 1980
Publication Information
Publication: Journal of Guidance and Control
Volume: 3
Subject Category
Spacecraft Instrumentation
Accession Number
80A47723
Funding Number(s)
CONTRACT_GRANT: NAS7-100
Distribution Limits
Public
Copyright
Other

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