Accuracy in orbital propagation: A comparison of predictive software models
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Authors
Wildt, Christopher F.
Subjects
orbital mechanics
orbital prediction software
orbital prediction software
Advisors
Luqi
Racoosin, Charles M.
Date of Issue
2017-06
Date
Jun-17
Publisher
Monterey, California: Naval Postgraduate School
Language
Abstract
Current analytical satellite vulnerability planning in the U.S. Space Surveillance System is reliant on two orbital propagators, PPT3 and SGP4, both of which have a foundation in similar theory. Since their first operational use, both propagators have incorporated updated theory and mathematical techniques to model additional forces in the space environment, causing their calculation methods to diverge over time. The aggregate effects of these diverging mathematical techniques cause calculation differences for perturbations of an orbit over time, resulting in differences in future predicted positions from PPT3 and SGP4, as well as differences in their accuracy. The atmospheric model within each propagator is determined to be the most effective component of each propagator to test, as the theoretical atmospheric drag calculation methods of PPT3 and SGP4 differ greatly. PPT3 and SGP4 both perform well within the expected accuracy limits inherent with analytical models, with neither propagator demonstrating an accuracy rate decay that was significantly better or worse than the other. Compared to ground truth observations, both propagators demonstrate decreased accuracy for satellites under greater effects from atmospheric drag, i.e., satellites that are closer to the Earth. Satellite vulnerability planning with these propagators should therefore utilize the most current TLE data available to avoid accuracy errors.
Type
Thesis
Description
Series/Report No
Department
Space Systems Academic Group (SSAG)
Organization
Identifiers
NPS Report Number
Sponsors
Funder
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Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.