A Parallel Robotic Antenna Design for Downlinking Leo Satellite Signal Subject to Wind Disturbance

Abstract

Passive LEO (Low Earth Orbit) satellites are a telecom premier option. However, LEO satellites impose not only stringent specifications on the resolution, precision and repeatability but also requiring advanced antenna technology for signal downlinking. To efficiently downlink LEO signals at each passage onto a given Earth region, we explored large size passive Earth antenna and an array of smaller size active Earth antennas to minimize the trajectory loss. To guarantee design specifications, the dynamics cannot be neglected given the size and inertia of base and antenna. In this paper, it is proposed the design, path planning and control of a six DoF robotic antenna maneuvering the antenna subject to aerodynamic wind disturbance. The system maneuvers to point at the LEO satellite over the whole envelope with the required precision to guarantee robust point-to-point tracking. Representative simulation results for three geolocations shows practical tracking with off-the-shelf-component actuators, without requiring any knowledge of the dynamics while withstanding state-dependent persistent disturbances.

Keywords

• Gough–Stewart platform
• parallel robot
• online trajectory generation
• LEO satellite
• downlink tracking