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Earth Observing System Covariance RealismThe purpose of covariance realism is to properly size a primary object's covariance in order to add validity to the calculation of the probability of collision. The covariance realism technique in this paper consists of three parts: collection/calculation of definitive state estimates through orbit determination, calculation of covariance realism test statistics at each covariance propagation point, and proper assessment of those test statistics. An empirical cumulative distribution function (ECDF) Goodness-of-Fit (GOF) method is employed to determine if a covariance is properly sized by comparing the empirical distribution of Mahalanobis distance calculations to the hypothesized parent 3-DoF chi-squared distribution. To realistically size a covariance for collision probability calculations, this study uses a state noise compensation algorithm that adds process noise to the definitive epoch covariance to account for uncertainty in the force model. Process noise is added until the GOF tests pass a group significance level threshold. The results of this study indicate that when outliers attributed to persistently high or extreme levels of solar activity are removed, the aforementioned covariance realism compensation method produces a tuned covariance with up to 80 to 90% of the covariance propagation timespan passing (against a 60% minimum passing threshold) the GOF tests-a quite satisfactory and useful result.
Document ID
20160010501
Document Type
Conference Paper
Authors
Zaidi, Waqar H. (Omitron, Inc. Greenbelt, MD, United States)
Hejduk, Matthew D. (Astrorum Consulting, LLC Waco, TX, United States)
Date Acquired
August 22, 2016
Publication Date
September 13, 2016
Subject Category
Astrodynamics
Report/Patent Number
GSFC-E-DAA-TN34455
Meeting Information
AIAA Space 2016(Long Beach, CA)
Funding Number(s)
CONTRACT_GRANT: NNG14VC09C
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Realism
Probability
Covariance

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