The "Denied Areas" project, led by the Federal Office for Cartography and Geodesy (BKG), focuses on developing robust positioning systems for use by emergency services in environments where GPS and traditional positioning systems are ineffective. These environments include underground car parks, subway stations, tunnels, and densely built-up urban areas. By leveraging small-format inertial navigation systems (INS) and integrating data from multiple sensors, the project aims to reliably track personnel movement and provide real-time position data, which is vital for navigation, situational awareness, and coordination of emergency teams. The project's methodology includes using sensor fusion to enhance the precision of positioning and secure data transmission to share critical information across all emergency response stakeholders. This effort will ultimately improve operational efficiency, reduce response times, and enhance safety during rescue operations in GPS-denied areas.