Review of propagation aspects of highly elliptical orbits

Propagation characteristics of land mobile satellite links are a major factor governing the viability of such a system. The main problems arise due to shadowing and multipath effects caused by the nature of the environment in the vicinity of a mobile. Due to the complexity of the process the land mobile propagation problem has not yet been completely solved by analytical means although partial analytical solutions, which have shown reasonably good agreement with the measurements, have been suggested. The most useful approach has been to conduct experiments and then use the data for system studies. In the paper the basic propagation theory, prevalent channel models and measurement results of a land mobile satellite channel are reviewed. The emphasis is on their applicability to high elevation angle satellite paths