Download: Standard Power Vectors for Optical Satellite Downlinks

Optical Data Downlinks from Low Earth Orbit satellites, through Directed Laser Beams, are prone to influences by the atmospheric index-of-refraction turbulence (IRT) and to satellite attitude vibrations. 
While the first effect leads to intensity-scintillations of the signal field, the second leads to beam wander and according fading. The subsequent received-power instability might be compensated at the Optical Ground Station by according means, like diversity, or forward error correction together with interleaving.

To ensure comparable results when different parties are simulating the performance of optical ground stations, equal behaviour of the physical channel is required. To enable such, DLR generated several received optical power vectors each with 100s duration and a sampling resolution of 10kS/s. These vectors can be downloaded here from their respective subfolders, in Matlab-format, including their statistical evaluation.

All vectors with atmospheric scintillation-only were normalized to a mean of one, while those also bearing pointing-fading do show the respective pointing-loss. However, no further link-budget losses such as distance-losses, atmospheric attenuation, or wavefront-erros, were implemented. Also the receiver's senstivity run from received power has to be added to the processing, as well as  FEC or other error control.

Details on the power vectors such as link elevation, carrier wavelength, or receiver aperture can be found in "FadingVectors for O3K coding simulations with RFE-model 20221019.pdf".

The other PDFs in this folder serve as further-reading on this topic.

It is planned that more power vectors will be added later, such as for directed optical UPlinks.


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