| Abstract: | The first generation of global satellite systems for personal and mobile communications is preparing to start commercial services. Service quality and availability are paramount to the user's acceptance of the service. For satellite systems, service quality and availability build up from satellite visibility, propagation conditions and equipment availability. This paper discusses the impact of elevation angle on visibility and propagation, that of azimuth separation between visible satellites, and compares multiple visibility statistics of all first-generation non-geostationary communications systems, namely Iridium, Globalstar, ICO, Ellipso and ECCO. © 1998 John Wiley & Sons, Ltd. |
