NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Ulysses orbit determination at high declinationsThe trajectory of the Ulysses spacecraft caused its geocentric declination to exceed 60 deg South for over two months during the Fall of 1994, permitting continuous tracking from a single site. During this time, spacecraft operations constraints allowed only Doppler tracking data to be collected, and imposed a high radial acceleration uncertainty on the orbit determination process. The unusual aspects of this situation have motivated a re-examination of the Hamilton-Melbourne results, which have been used before to estimate the information content of Doppler tracking for trajectories closer to the ecliptic. The addition of an acceleration term to this equation is found to significantly increase the declination uncertainty for symmetric passes. In addition, a simple means is described to transform the symmetric results when the tracking pass is non-symmetric. The analytical results are then compared against numerical studies of this tracking geometry and found to be in good agreement for the angular uncertainties. The results of this analysis are applicable to the Near Earth Asteroid Rendezvous (NEAR) mission and to any other missions with high declination trajectories, as well as to missions using short tracking passes and/or one-way Doppler data.
Document ID
19950021366
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Mcelrath, Timothy P.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Lewis, George D.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1995
Publication Information
Publication: NASA. Goddard Space Flight Center, Flight Mechanics(Estimation Theory Symposium 1995
Subject Category
Astrodynamics
Accession Number
95N27787
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
No Preview Available