Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2015. / A precise orbit propagator was developed for implementing on a CubeSat's on-board computer
for real-time orbital position and velocity determination and prediction. Knowledge
of the accurate orbital position and velocity of a Low Earth Orbit (LEO) Cubesat is required
for various applications such as antenna and imager pointing. Satellite motion is
governed by a number of forces other than Earth's gravity alone. The inclusion of perturbation
forces such as Earth's aspheric gravity, third body attraction (e.g. Moon and
Sun), atmospheric drag and solar radiation pressure, is subsequently required to improve
the accuracy of an orbit propagator.
Precise orbit propagation is achieved by numerically integrating a set of coupled second
order differential equations derived from satellite's perturbed equations of motion. For
the purpose of this study two numerical integrators were selected: RK4 - Fourth order
Runge Kutta method and RKF78 - results from embedding RK7 into RK8. The former is
a single-step integrator while the latter is a multi-step integrator. These integrators were
selected for their stability, high accuracy and computational efficiency. An orbit propagation software tool is presented in this study. Considering the processing
power of Central Processing Unit (CPU) of CubeSat's on-board computer and a trade-off between precision and computational cost, the 10 x 10 and 20 x 20 gravity field models, the Exponential atmospheric model and Jacchia 70 static atmospheric model, were implemented. A 60 x 60 gravity field model is also investigated for reference. For validation purpose the developed software tool results were compared with results from Systems Tool Kit (STK) and Satellite Laser Ranging (SLR) using SUNSAT satellite reference orbit. / National Research Foundation
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:cput/oai:localhost:20.500.11838/2196 |
| Date | January 2015 |
| Creators | Tshilande, Thinawanga |
| Contributors | Opperman, B. D. L., Van Zyl, R. R., Cape Peninsula University of Technology. Faculty of Engineering. Department of Electrical, Electronic and Computer Engineering. |
| Publisher | Cape Peninsula University of Technology |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | http://creativecommons.org/licenses/by-nc-sa/3.0/za/ |
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