Before May 1, 2000 – when President of USA Bill Clinton ordered to remove the intentional performance degradation of GPS (Global Positioning System) – satellite-based navigation was considered a niche of the entire space market and main users were military forces. That day changed dramatically the destiny of satellite navigation: in fact, the increased accuracy for civilian GPS receivers, induced by Clinton’s decision, has opened the way to an avalanche of novel services, new typologies of users, advanced integration architectures to both existing systems and newly conceived ones. The satellite navigation world is hence experiencing a quick and fascinating evolution; and if we believe that a book is a sign of a time worth of being described on a permanent form, this is certainly the time to write a book on satellite navigation. The question is, which book on navigation do we need at present? GPS and its modernization plan seem mature for several civilian applications; the US Department of Defense is studying the new generation system GPS-III; Europe, through a joint venture between the European Commission and the European Space Agency, is living the fascinating challenge of developing GALILEO, whose preliminary phases have been completed. In the meantime, thanks to the success of GPS, the awareness of navigation users about the incredible potential of Global Satellite Navigation Systems (GNSS) continuously increases. In this frame, the deployment of satellite-based Augmentation Systems in various countries (e.g. WAAS in USA and Canada, EGNOS in Europe, MSAS in Japan, GAGAN in India, SNAS in China), as well as ground and aircraft based augmentations, is somehow filling the gap between the navigation users’ dreams and the time-to-deployment of the second generation GNSS (i.e. GALILEO and GPS III). Another interesting aspect in the evolving picture of the navigation world concerns integration with communications systems: wireless network designers have become fully aware about the importance of localization for advanced services and they are ready to implement satellite navigation technologies in new generation user terminals. The above frame highlights that it is now the time to write a book focused on future trends of satellite navigation, taking a broad picture about the past, capturing the present evolution and challenges and envisaging the directions for an effective exploitation of navigation services in the user-centric global vision of the future. The book provides a deep technical, scientific and strategic vision of navigation systems belonging to different countries and in various development stages. Authors aimed at focusing with the same depth on the technical/architectural aspects and the user-related aspects (terminals, services, security, guarantees) of satellite navigation, harmonizing them with legal/market issues as well as with hints and thoughts for new proposals and initiatives in the field. Due to its multipurpose nature, the book can be used at various educational levels, including M.Sc and Ph.D students that can find it beneficial as reference/design book and perspective source. At the same time, the book is suited for professional engineers and managers, as an aid in consolidating a future vision about the navigation world and in the subsequent planning and strategic decision-process. The reader is offered a large view on the navigation world along the ten Chapters of the book, moving from the navigation historical and analytical fundamentals (Chapters 1 and 2, respectively) through the description of present and future milestones of the satellite navigation scenario - GPS (Chapter 3), Augmentation Systems (Chapter 4), GALILEO (Chapter 5), GPS modernization and GPS III (Chapter 6) - up to key-aspects for the future trends in navigation: legal and market policy (Chapter 7), services (Chapter 8), integration with existing and future systems (Chapter 9), finally concluding with the open issues and perspectives (Chapter 10) of the fascinating navigation adventure.