Scheduling Space-to-Ground Optical Communication Under Cloud Cover Uncertainty

Abstract

Any reliable model for scheduling optical space-toground communication must factor in cloud cover conditions due to attenuation of the laser beam by water droplets in the clouds. In this work, we provide two alternative models of uncertainty for cloud cover predictions: a Robust Optimisation model with a polyhedral uncertainty set and a Distributionally Robust Optimisation model with a moment-based ambiguity set. We computationally analyse their performance over a realistic communications system with one satellite and a network of ground stations located in the United Kingdom. The models are solved to schedule satellite operations for six months utilising cloud cover predictions from official weather forecasts.We found that the presented formulations with the treatment of uncertainty outperform in the long term models in which uncertainty is ignored. Both treatments of uncertainty exhibit similar performance. Nonetheless, the novel variant with the polyhedral uncertainty set is considerably faster to solve.

Advances in space quantum communications

“…A particular problem for free‐space optical communications (FSOCs) is the effect of adverse atmospheric conditions such as cloudy weather. This affects all space‐ground optical link schemes and various mitigations have been explored such as receiver geographic diversity [293]. These measures could equally apply to SatQKD but there is also the possibility of utilising wavelengths with better penetration of partially obscured skies, particularly in the mid to long infrared region of the spectrum [294].…”