A Review on Airspace Design and Risk Assessment for Urban Air Mobility

The increasing deterioration of urban traffic congestion has led to the emergence of Urban Air Mobility (UAM). UAM seeks to reduce congestion by offering flexible and efficient aerial transportation using electric vertical take-off and landing aircraft (eVTOL) and unmanned aerial vehicles (UAV). As UAM evolves, the guarantee of the effectiveness and safety of UAM aircraft has become an essential task. Thus, UAM airspace design and risk assessment are vital. This paper reviews and synthesizes the latest research on UAM airspace design and risk assessment. Initially, it outlines the ideas of UAM airspace categorization and geofencing. Subsequently, it presents three approaches to organizing UAM airspace: gridding, stratification, and networking, emphasizing their benefits, limitations, and uses. In addition, it contrasts four commonly used UAM airspace structure models. In the next step, the article introduces relevant risk assessment principles and analyzes four prominent collision risk assessment models, pointing out their merits and drawbacks. In conclusion, the paper highlights the current research challenges and proposes future research directions.