Mobile broadcast geostationary satellite system propagation measurements using GPS signals

This paper deals with the urban propagation characteristics and satellite-diversity (Sat. D) characteristics of mobile broadcast geostationary satellite system by using the GPS (Global Positioning System) signals. For designing digital broadcast from geostationary satellite, it must be clarified the shadowing characteristics by urban building, electrical light poles and trees etc. Southern orbital are GPS satellite signals with elevation angle between 40 similar to 50 degrees data are used for propagation characteristics, rather than actual geostationary satellite, e.g., the N-STAR. This new measuring method has several merits, i.e., low measuring equipment cost, easy data accumulation (i.e., satellite position, receiver position and height, received signal levels etc.). A receiving system on a vehicle measured signals fades caused by shadowing building etc. As a result, west to east urban roads are heavily attenuated. Furthermore, to overcome this attenuation, the Sat D characteristics are processed from measured data. From processing results, more than 90 % satellite visibility percentage can be achieved in urban city by selecting two diversity satellites with separation angles more than about 45 degrees.