A proposal for a common metric for drone traffic density

In the last few years, advances in technology, real-time communication and networks have triggered high interest for unmanned aerial vehicles (UAV), also known as drones. The possibility of thousands of drones flying over cities poses a major challenge to the safe sharing of airspace. Therefore, methods of safe separation between drones and manned aircraft in a demanding urban environment should be further investigated. However, there is a need to first define the drone traffic density in order to conduct a realistic simulation. Several research projects have tackled the safety of UAV operations and traffic organization in an urban airspace. From these, we selected the seven most relevant publications for our study that deal with drone traffic density. We conducted an in-depth analysis of their simulation setup of drone traffic densities. However, their approaches were too different to compare directly. This paper outlines our approach to determine the drone traffic density by adopting a comparison metric of average simultaneous drone flights per square kilometer. The outcome of the analysis allowed us to calculate the most suitable reasonable traffic density over the city of Hannover when simulating the separation method for the USEPE project.