Reference systems -- Satellite orbits -- Satellite signals -- Observables -- Mathematical models for positioning -- Data processing -- Data transformation -- GPS -- Glonass -- Galileo -- More on GNSS -- Applications -- Conclusion and outlook. "GNSS - GPS, GLONASS, Galileo and more" is the extension of the scientific bestseller "GPS - Theory and Practice" to Global Navigation Satellite Systems (GNSS) and includes the Russian GLONASS, the European system Galileo, and additional systems. The book refers to GNSS in the generic sense to describe the various existing reference systems for coordinates and time, the satellite orbits, the satellite signals, observables, mathematical models for positioning, data processing, and data transformation. With respect to the individual systems GPS, GLONASS, Galileo and more, primarily the specific reference systems, services, the space and the control segment, as well as satellite signals are described. Furthermore, augmentations by space- and ground-based systems are discussed. This book is a university-level introductory textbook and is intended to serve as a reference for students as well as for professionals and scientists in the fields of geodesy, surveying engineering, navigation, and related disciplines.