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 GPS (Global Positioning System) signals. For designing digital broadcasting from geostationary satellites, it must be clarified the shadowing characteristics by urban buildings, electrical light poles and trees etc. Southern orbital arc GPS satellite signals with elevation angles of 46/spl sim/50 degrees data are used for the propagation characteristics, rather than an 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 signal fades caused by shadowing buildings 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 an urban city by selecting two diversity satellites with separation angles more than about 45 degrees.