GNSS Positioning and Challenges

The global navigation satellite system (GNSS) is a widely used wireless positioning system that offers accurate and reliable positioning, navigation, and timing services. This chapter introduces GNSS positioning and the challenges. The chapter begins with a basic GNSS processing flow with a focus on traditional GNSS signal processing, followed by GNSS challenges. To address the challenges, advanced GNSS processing techniques such as vector tracking loops and direct position estimation are introduced. The chapter ends with a brief introduction of aided GNSS positioning techniques, which are detailed in the following chapters.