Narrowband channel statistics from multiband propagation measurements applicable to high elevation angle land-mobile satellite systems

Results from a multiband propagation experiment for a high elevation angle land-mobile satellite (LMS) channel are presented. A small helicopter was used to fly the transmitter module, transmitting frequencies in the L, S, and Ku bands. A vehicle equipped with the corresponding receivers and data acquisition system was followed by the helicopter on the selected routes. The measurement campaign was undertaken in two phases in September 1991 and in April 1992. The results show considerable decrease in signal attenuation when the path elevation angle is high due to reduced shadowing. In general, the attenuation increases with the increasing radio frequency. Foliage density has also been found to influence the fade levels, especially at higher path elevation angles. The overall analysis of the propagation data indicates that the fading character of the LMS channel is significantly dependent on the surrounding environment