Characteristics of the Service Provided by Communications Satellites in Uncontrolled Orbits

In a communications system which uses satellites in uncontrolled orbits, there would be times when the communication between two stations would be interrupted because no satellites would be in view. This paper provides material which can be used to describe the service which a random system of satellites would provide. An example system which could be used to provide initial world-wide service is also discussed. This system has certain nonrandom characteristics, and the effect of these characteristics on the service to various parts of the world is examined by computer simulation. TABLE I. INTRODUCTION I I . SATELLITE ORBITS OF CONTENTS Page 1622 1623 2.1 2.2 2.3 2.4 Orbit altitude 1623 Satellite period 1624 Orientation of the orbit relative to the earth 1624 Relative orientation of orbit planes and relative posit ions of satellites 1626 1626 SATELLITE VISIBILITY 3.1 Visibility geometry 3.2 The probability that a satellite is mutually visible 3.2.1 Numerical determination of p 3.2.2 Variations in p 3.2.3 A partial table of p IV. SERVICE PROVIDEO BY SATELLITES IN RANDOM ORBITS 1626 1629 1629 1629 1631 1632 1632 4.1 Quality of service, q .···;···.· 4.1.1 Satellites in orbits of the same altitude and inclination Single satellite visibility Multiple satellite visibility 4.1.2 Mixed orbits 4.1.3 The effect of overlap of mutual visibility regions 4.2 Description of the periods of service and no-service by simulation. 4.2.1 Description of service for various qualities of service 4.2.2 The effect of orbit altitude on the service 4.3 Analytical description of the periods of service and no-service.