ABSTRACT
This chapter discusses the basic working principle of GNSS to prepare the reader for concentration on core technical matters in the subsequent chapters. It starts the discussion with triangulation and trilateration mathematically and then proceeds to address almanac and ephemeris data, timing and ranging concepts, and signal related parameters. One of the differences between land-based trilateration and GNSS is that the distances (called ranges) in land-based systems, are measured to reference points on the surface of the earth. In GNSS, they are measured to satellites that are orbiting thousands of kilometres above the earth; and performing measurements from moving references is much more challenging than from fixed references. This chapter explains this range determination concept briefly and provides an introductory idea of getting one’s position using a GNSS. There are also several intrinsic matters involved which are necessary to be addressed to understand the technological background thoroughly; in Chapters 4, 5, and 6, we shall have a closer look at these issues. Hence this chapter will act as a foundation to the next three chapters.
