Implications of 4D weather cubes for improved cloud free line of sight assessments of free space optical communications link performance

Abstract

This study advances the benefits of previously reported 4D Weather Cubes towards creation of high fidelity cloud free line of sight (CFLOS) beam propagation for realistic assessment of auto-tracked/dynamically routed free space optical communication datalink concepts. 4D Weather Cubes are the product of efficient processing of large, computationally intensive, National Oceanic and Atmospheric Administration (NOAA) gridded numerical weather prediction (NWP) data coupled with embedded physical relationships governing cloud, fog, and precipitation formation to render highly realistic 4D cloud free line of sight analytical environments. The Weather Cubes accrue parameterization of optical effects and custom atmospheric resolution through implementation of the verified and validated Laser Environmental Effects Definition and Reference (LEEDR) atmospheric characterization and radiative transfer code. 4D Weather Cube analyses have recently been expanded to accurately assess Directed Energy weapons and sensor performance (probabilistic climatologies and performance forecasts) at any wavelength/frequency or spectral band in the absence of field test and employment data. The 4D Weather Cubes initialize the High Energy Laser End to End Operational Simulation (HELEEOS) propagation code, which provides a means to dynamically point the communication link. HELEEOS’ calculation of irradiance at the detector as a function of transmission, optical turbulence, and noise sources such as path radiance was the basis for comparative percentile performance binning of FSO communication bit error rates as a function of wide-ranging azimuth/elevation, earth-to-space uplinks. The aggregated, comparative bit error rate binning analyses for different regions, times of day, and seasons using a full year of data provided numerous occasions of clouds, fogs, and precipitation events, thus demonstrating the relevance of 4D Weather Cubes for adroit management of CFLOS opportunities to enhance performance analyses of point-to-point as well as evolving multilayer wireless network concepts.