Channel Characterization and Modeling for LEO-Ground Links

Kurzfassung

This chapter describes low Earth orbit to ground optical communications. The scenario is outlined and introduction to atmospheric turbulence in this slant geometry is given. The scintillation index of incident intensity and aperture averaged received power are given by means of evaluation of common analytical expressions. Furthermore, the most important statistical parameters of fading are introduced and given. The new part in this chapter is the presentation of an analysis of satellite-ground measurements with two apertures (40 and 5 cm diameter). The experiment campaign is outlined as well as the results of the individual measurements. The power scintillation index and fading statistics are calculated over satellite elevation angle and averages of the measurements are created and compared to common theory. The measurements match quite well weak fluctuation theory. The theory is also used to extrapolate the measurements of power scintillation index, which were taken at a wavelength of 847 nm, to the wavelength of interest 1550 nm.