“The objective of the PATHfinder project (PNT as A TecHnology to support a scalable Fleet of lINked Drones operating in BVLOS scenarios for preventive monitoring and Emergency missions) is to design and implement a cooperative system for challenging scenarios (difficult to access and with a ‘wide extension), using data from different sensors that can be used in parallel, with real-time information of the observed scenario, suitable for persistent surveillance, monitoring, emergency response and the adoption of adequate measures in response to major disasters .