Gerhard Schall overviews research activities related to mobile augmented reality in indoor as well as outdoor environments. These activities have emerged over several years, especially around the topics of positioning, sensor fusion, spatial modelling as well as in the fields of ubiquitous computing. The innovative and contemporary character of these topics has led to a great variety of interdisciplinary contributions. The author gives insights into the evolution of mobile augmented reality prototypes for industrial applications, such as X-Ray visualisation of 3D models of the underground infrastructures which is registered correctly in the users view.