Multi-Depot Contingent sUA Operations with UTM Services in Urban Environments: A Simulation-Based Study

This report presents simulation-based studies that quantitatively assess the collision risk mitigation between small unmanned aircraft (sUA-to-sUA) in the presence of integrated 4D volume-based pre-departure strategic deconfliction (SD) and conformance monitoring for situational awareness (CMSA) services within the small unmanned aircraft systems (sUAS) traffic management (UTM) ecosystem. To achieve the target level of safety in terms of collision risk, this study also attempts to comprehend the necessity of additional UTM services in addition to CMSA with pre-departure SD. This study specifically focuses on conflicts between small unmanned aircraft (sUA-to-sUA) that originate from different depots and belong to different operators. First, in this study, NASA’s Flexible Engine for Fast-time Evaluation of Flight Environments (Fe3) simulator is integrated with CMSA and 4D volume-based pre-departure SD modules for simulation-based studies. Next, the Fe3 simulator is utilized to execute the designed simulation scenarios, incorporating varying percentages of randomly generated contingent sUA flights and differing levels of UTM services. Lastly, a data analysis is conducted, considering sUA traffic flow for different scenarios and sUA-to-sUA conflicts between flights originating from different depots. According to simulation-based research, CMSA and 4D volume-based pre-departure SD services work together to mitigate the risk of sUA-to-sUA conflicts in sUA traffic that includes both conforming and contingent sUA. This approach is more effective in avoiding sUA-to-sUA conflicts than using 4D volume-based pre-departure SD service alone. However, results show that the integration of CMSA with a 4D volume-based pre-departure SD fails to resolve all sUA-to-sUA conflicts. For example, conflict between nominal sUA and contingent sUA flights, if the nominal flight is already airborne when a contingent flight is detected and declared. The results also indicate that the location of the emergency landing port for contingent sUA flights plays a critical role in mitigating the collision risk.