**1. Introduction**

Navigation systems are a study field that focuses on the process of monitoring and controlling the movement of an entity from one place to another. General, navigation systems may- be entirely on board an entity, or they may be located elsewhere and communicate via radio- or other signals with an entity, or they may use a combination of these methods. It means that- navigation systems can refer to any skill that involves the determination of position and direction compared to known locations or patterns and, simultaneously, navigation strategies can- include several general categories varying in the environment and navigator's substance. The- book "Navigation Systems" provides a platform for researchers, academics, PhD students and- other scientists to review, plan, design, analyze, evaluate, intend, process and implement diversiform issues of navigation systems. Topics of this book include some new methods, approaches- and algorithms for applications in human and machine navigation systems. Five book chapters demonstrate capabilities and potentialities of navigation systems to solve scientific and- engineering problems with a varied degree of the complexity. The first two chapters related- to satellite navigation systems provide details of high-precision dynamic location and airborne- double-antenna orientation approach. The second three chapters associated with human navigation systems demonstrate possibilities of utilizing modern technologies in navigation systems with the aim of helping common users and physically and/or visually impaired persons.-
