What is it about?

An orbit design methodology for repeating ground tracks with minimal altitude variations, suitable for low inclination orbits, was studied and developed. This paper offers two key contributions - (1) it reviews pre-existing repeat ground track reference orbit design methods for polar orbits, and assesses their feasibility for near-equatorial orbits; (2) it counter-proposes a more efficient orbit design method that circumvents convergence issues during the optimisation procedure.

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Why is it important?

Such reference trajectories are useful in remote sensing and navigation, particularly where there is a need to revisit a particular location over the Earth with a very specific geometry and viewing angle.


A near-equatorial repeating ground track and frozen orbit has never been proposed before until this study, and thus the authors hope that this study serves as a useful numerical recipe for orbit design methods, especially when applying designing them for revisits at low-latitude geographies.

Samuel Y. W. Low
DSO National Laboratories

Read the Original

This page is a summary of: Designing a Reference Trajectory for Frozen Repeat Near-Equatorial Low Earth Orbits, Journal of Spacecraft and Rockets, June 2021, American Institute of Aeronautics and Astronautics (AIAA),
DOI: 10.2514/1.a34934.
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