Robust and Efficient Communications for UAM

Abstract

The management of the urban air space, called UTM (Unmanned Aircraft System Traffic Management) with, will have to be carried out differently than it is currently handled in civil aviation due to expected high traffic densities and short reaction times needed in dense urban environments. UTM will rather rely on pre-planned, conflict-free trajectories and their continuous monitoring. The realization of such a UTM concept will at least partially make use of existing communication infrastructure such as cellular communications. Under ideal conditions, this approach seems sufficient at first, but on closer inspection, weaknesses become visible, such as a lack of redundancy or a missing higher-level safety net as it is common in todays civil aviation and ship traffic and already planned for the future autonomous driving. Therefore, we see the need to introduce an additional, decentralized and robust communications concept for UAM that enables a reliable information exchange of position trajectories directly between UAs in order to avoid collisions between all urban airspace users. However, there is currently no commercial communication system available that addresses the future requirements for the safe and efficient information exchange between flying vehicles while considering the specific and challenging signal propagation characteristics in urban environments. The transmitted electromagnetic signals are reflected, scattered and diffracted by all kinds of obstacles like buildings, trees, or other vehicles, leading to a rich multipath environment. In addition, we expect strong non-line-of-sight (NLOS) conditions due to shadowing by relatively high surrounding buildings and frequent topology changes, in which the receiver only receives overlapped reflected and diffracted signals. Furthermore, the realization of applications like the U-space services will define, which amount of information will have to be exchanged between which entities under certain latency constraints in order to ensure safe operation. Within the scope of the DLR project HorizonUAM, we develop a such a communications concept that considers insights based on real-world measurements that have already been conducted with hexacopters in an urban scenario and addresses the future requirements. This talk will give an overview of our proposed communication concept and provide first findings from the measurements.