This book puts all together concepts and theories normally found only in separated books. GPS, inertial navigation and how to integrate both things normally require reading a lot of different articles and journals. These subjects are individually complex and demanding but its modern GPS concepts approach were deep enough to allow the proper correlation between the inertial theory and GPS through the Kalman Filtering. The book demands some previous and basic concepts knowledge regarding filtering. And if you are a self-made student you will miss the answers for the proposed problems which worth trying to solve. But it should not prevent you to buy this book. It is clear that the authors are not only one of main expertise on their area but know how to transmit their great experience.