Autonomous semi-major axis adjustment for mega constellation continuous coverage

Abstract

Mega constellations have larger number of satellites and higher distribution density compared with traditional constellations, that lead to huge tracking, telemetry and command (TT&C) requirement, heavy computation load for configuration design, and frequent configuration control due to low-Earth perturbations, collision avoidance emergencies, etc. This paper proposes a novel constellation control scheme for mega constellations with the same semi-major axis, that is based on the inter-satellite boundary constraints. Satellites do not follow the designed configuration, but keep bounded and stable flight with respect to adjacent satellites. The continuous coverage requirement is considered for priority. The inter-satellite continuous coverage constraint is formulated as right ascension of ascending node constraint and relative distance boundary constraint between every two adjacent coplanar satellites. To reduce control consumption, the boundary constraint is kept by adjusting the semi-major axes of coplanar satellites. To that end, the relationship between relative distance boundary and semi-major axis difference is studied. The semi-major axis adjustment strategy for a single satellite is proposed, and the control rules for coplanar satellites are determined. The proposed control method is verified in GW-2 sub-constellation, and is compared with relative station-keeping control method. Results indicate its effectiveness and good performance in control frequency and consumption.