Non-Geostationary Orbit Satellite Systems

Abstract

Until the late 1980s, satellites in non-geostationary orbit had limited use for communication applications because, in general, these systems are more complex and, since geostationary satellites met most requirements anyway, not much effort was spent on their development. Molniya orbit was used in the former Soviet Union for providing services to very high-latitude regions where geostationary orbit (GSO) systems were not very reliable. However, since the beginning of the 1990s there has been considerable interest throughout the world in the use of various types of non-geostationary orbits. In this chapter, we will discuss the reasons behind the revival of this interest, considerations in design of a non-geostationary constellation with an example, and various types of network-related issues. We will then give examples of some of the more technically interesting emerging non-geostationary systems.