Navigation fundamentally provides information on position, velocity and direction which are needed for travel in ocean, land, air and in space. The myriad forms of navigation developed so far are collectively called modern navigation. This recent text discusses new promising developments that will assist the students when they enter their future professional career. It is the outcome of authors' wide experience in teaching, research and development in the field of navigation and inertial sensors. The content of the book is designed to impart adequate knowledge to the students in the area of navigation and related sensors. The text discusses inertial navigation, inertial sensors, MEMS based inertial sensors, satellite navigation, integrated inertial navigation, signal processing of inertial sensors and their applications. The chapters introduce all the topics in an easy to understand manner so that an appreciative understanding of the text matter can be made without resorting to equations and mathematics. Considerable references have been provided to enable both the students and the professors to dwell and learn more on the topics of their interest. This textbook is primarily intended to meet the academic needs of undergraduate and postgraduate students of aerospace engineering and avionics