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Refraction effects on the Galileo probe telemetry carrier frequencyAs the Galileo probe relay radio link (RRL) signal propagates outward through the Jovian atmosphere, the atmosphere will manifest itself in two ways. First, the geometric path length of the signal is increased, resulting in a small change of the RRL signal departure angle from the proble (transmitter). Secondly, the velocity of the signal is decreased. For a spherical, static atmosphere with a known profile of refractivity versus altitude the effects of refraction on the RRL frequency can be found using a variation of standard ray-tracing techniques, whereby the ray departure angle is found by an iterative process. From the dispersive characteristics of a mixture of hydrogen and helium with trace amounts of methane and ammonia a simple model of the Jovian atmosphere is constructed assuming spherical symmetry and uniform mixing. The contribution to the RRL Doppler frequency arising from refraction is calculated, and its effect on the Doppler wind measurements is discussed.
Document ID
19910042589
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Atkinson, D. H.
(Idaho, University Moscow, United States)
Spilker, T. R.
(Stanford University CA, United States)
Date Acquired
August 14, 2013
Publication Date
February 1, 1991
Publication Information
Publication: Radio Science
Volume: 26
ISSN: 0048-6604
Subject Category
Lunar And Planetary Exploration
Accession Number
91A27212
Funding Number(s)
CONTRACT_GRANT: NGT-50075
Distribution Limits
Public
Copyright
Other

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