Clear-Air Propagation Simulations for HAPs using Radiosonde Data

Propagation of electromagnetic waves on the slant paths from high altitude platforms to ground stations is studied under so called "clear-air" conditions. A simulation framework for modelling of propagation on the slant paths is developed. Measured radiosonde atmospheric data is utilized to determine atmospheric refractivity vertical profiles in the first 20 km above the ground. Then, the refractivity profiles are used in simulation of propagation for different frequencies and elevation angles. Received signal level fluctuation statistics are calculated and analyzed.