Overview of Global Positioning Systems

This chapter discusses the fundamentals of satellite navigation. It introduces the fundamentals of the global position estimation using time-of-arrival estimation of signals received from a cluster of satellites. The chapter assesses the impact of the satellite constellation geometry on the global positioning accuracy. It presents an overview of current and future global navigation satellite systems, signal formats, and modulations. The chapter provides an overview of differential correction and augmentation systems presenting both local and wide-area differential systems, as well as other augmentation strategies that are common in the current application scenario (i.e., assisted global navigation satellite systems (AGNSS) via communication networks). Examples of augmentation systems capable of improving the positioning performance are briefly presented. The chapter also presents examples of terrestrial and satellite systems complementary to the baseline satellite constellation and able to improve the positioning performance.