Satellite look angles, track and geometry in Mobile Satellite Communications

Abstract

This paper describes Satellite Look Angles, Track and Geometry in the Space and their significance with regard to the spacecraft use for Mobile Satellite Communications (MSC) systems. Basic geometric theory of satellite coordinates is applied to determine the geographical azimuth and elevation (spacecraft altitude) angles required to point mobile satellite tracking antenna to the Geostationary Earth Orbit (GEO) or Non-GEO communication satellites. The mathematical treatment introduced in this paper takes into consideration circular and elliptical orbits. During more than three decades, commercial MSC networks have utilized GEO satellites extensively to the point where orbital portions have become crowded; coordination between satellites is becoming constrained and could never solve the problem of polar coverage. However, other Non-GEO MSC solutions have recently grown in importance because of their orbit characteristics and coverage capabilities in high latitudes and Polar Regions. The important parameters of the Satellite Look Angles such as Elevation and Azimuth angles and Satellite Track and Geometry such as Longitude and Latitude values are described.