Three years of optical satellite to ground links with the T-AOGS: data transmission and characterization of atmospheric conditions

Abstract

After more than 3 years of operational experiences with the Transportable Adaptive Optical Ground Station (T-AOGS) it is not any more the question whether optical communication through atmosphere is possible for Geo to ground applications. It is important to understand the performance of optical communication under different atmosphericconditions and which the key parameters are to improve simplicity, robustness and availability of optical bi-directional satellite to ground links (SGL). We report within this paper on the characterization of the atmospheric channel for ground to GEO optical communication without adaptive optics correction in the uplink. Besides the telemetry data of the space segment and the T-AOGS, also a special measurement campaign was carried out using the 1m telescope of the ESA-OGS in parallel. An outlook for further analysis and activities is given.

Characterisation of the optical channel GEO to ground: using five years of data from Alphasat TDP1 and T-AOGS for investigation of different conditions

“…As the distribution of data over the day and over the year is not balanced (see Figure 1), this average is also not fully balanced. In contrast to the single CHUNKs shown in section 3, or the data from one summer campaign shown in [7] the observed results or not any more single examples, but an overview based on large statistics. Only the numbers for links with the 95 mm T-AOGS transmitter aperture should be considered carefully: only a few links during noticeable good weather conditions were performed.…”

Link budget analysis of bi-directional LEO and GEO optical feeder links advancing the beam wander model’s accuracy

“…Regarding the turbulence model, the Maui3 profile, developed for another OGS site with characteristics similar to the Tenerife one, results to be the most representative of measurement data 46 . Thus, as for the previous scenario, the tool has been extended implementing this model, whose mathematical expression can be found in 48 .…”

“…For what concerns pointing errors, the tracking system of the LCT shows a residual tracking error during communications with root mean square value σ jitt = 0.07 µrad 45 . At the same time, the T-AOGS alignment was adjusted for each link by an operator, reducing the static pointing error up to �θ OGS = 10 µrad 46 .…”