Forecasting of turbulence impact on optical link from geostationary satellite

Abstract

With the development of optical links for space-ground communications comes the need to mitigate the effects of the atmospheric turbulence to guarantee a lossless connection. By having a network of addressable ground stations we want to guarantee to always target a point where the link is available. For this to work, we need to be able to predict the forthcoming link availability for each station while keeping costs low. We have developed a method that allows, in the geostationary case, to obtain the power margin on the link without exhaustive knowledge of the turbulence state. In this work, we show that the sole knowledge of 4 integrated parameters of the turbulence profile (Cn²) and associated wind profile, which can be measured with low-complexity instruments, provides us with enough information to entirely describe the statistics of the received optical power after an adaptive optics correction. We further develop the method to take into account digital mitigation techniques (interleaving and numerical error correction) and obtain the link power margin with a maximum error compatible with current assumptions made in commonly used link budgets.