Ch 15 GNSS Receiver Signal Tracking

Chapter Overview: This chapter provides an integrated overview of the fundamentals of GNSS signal tracking and the latest developments in advanced signal tracking techniques to improve sensitivity, robustness, and accuracy of performances. The chapter will start with the objectives of signal tracking, followed by a conceptual description of a closed-loop tracking system. A brief conventional treatment of code delay lock loop (DLL) is then presented. Carrier tracking is the more challenging and a more intensely researched subject. This chapter will summarize the conventional phase lock loop (PLL) design. Tracking of simulated GPS L1 signals will be used to illustrate the concepts presented in the traditional implementations of DLL and PLL techniques. Following the conventional PLL description, we present a state space-based feedback control theory to demonstrate that some of the popular carrier tracking loop implementations are fundamentally equivalent. PLLs using Proportion-Integration Filter (PIF), Wiener Filter (WF), and Kalman Filter (KF) implementations are discussed. Optimization strategies of carrier tracking for weak signals and for receivers operating on dynamic platforms are presented and their performances are analyzed. Finally, the latest developments in inter-frequency aiding will be summarized. The codes and data used to generate example implementations are available for readers to download from the authors’ website.

On this web site, you can:

• Get hi-res copies of selected figures from the chapter, for use with attribution.

• Download Matlab and Python codes to perform GPS signal tracking and simulated and real GPS IF signals in this chapter at this link: https://github.com/cu-sense-lab/gps-tracking-loop-example

• Provide feedback and errata corrections.