Wide infrastructures as industry plants and hospitals are vulnerable to causality events. In this paper, we presented a solution addressing the guiding personnel during maintenance and/or emergency conditions. The aim is to reduce the time needed to react and to cope with organization and maintenance support, while facilitating communication, and indoor/outdoor navigation. The solution is based on the formalization of protocol, the modelling of knowledge for navigation, the algorithms and the development of a mobile application and corresponding server device for integrated indoor/outdoor navigation. The introduction of the integrated indoor/outdoor navigation has constrained to a major restructuring of the software architecture of the application. The details are reported in the paper. The navigation algorithms are based on low costs mobile sensors and adaptive extended Kalman filter. The solution has been validated within a large medical infrastructure, thus demonstrating the validity of the identified modalities and procedures, measuring the advantage from both qualitative and quantitative aspects. The indoor navigation solution has been compared with other former solutions based on classical Kalman and dead reckoning (the former solution). The proposed solution for indoor navigation resulted to be better ranked with respect to the solution reviewed at the state of the art.