In the age of automation the ability to navigate persons and devices in indoor environments has become increasingly important for a rising number of applications. However, we are still far away from achieving cheap provision of global indoor positioning with an accuracy of 1 meter or better. With the emergence of global satellite positioning systems, the performance of outdoor positioning has become excellent, but many mass market applications require seamless positioning capabilities in all environments. Therefore indoor positioning has become a focus of research and development during the past decade. This book categorizes all sighted indoor positioning approaches into 13 distinct technologies and describes the measuring principles of each. Individual approaches are characterized and key performance parameters are quantified.