Up- and down- link atmospheric compensation experiment with Alphasat: design and initial results

Optical links suffer from distortions when propagating through the atmosphere. Countermeasures need to be implemented on both the receiver (post-compensation) and the transmitter (pre-compensation) to mitigate these atmospheric effects. One approach is to implement adaptive optics for pre- and post- compensation. The goal of the Alpha-up and Down experiment (AUDE) is to characterize the impact of atmospheric impairments on the optical link with and without adaptive optics in order to support link budget analysis, optical communication system design, operation, and optimization. This paper describes the design of the highly automated adaptive optics system for uplink pre-compensation and downlink post-compensation at the European Space Agency Optical Ground Station (ESA OGS) located at Observatorio del Teide, Tenerife. The system facilitates bi-directional optical links with Alphasat located in geo-stationary orbit. In total, four extensive measurement campaigns are planned, to assess diurnal and seasonal variations. This paper includes the initial results from the first of these measurement campaigns, conducted in September 2024.