A Detect and Avoid Concept for Safely Managing Multiple Hazards in Remotely Piloted Aircraft Systems*

Despite the huge research effort in the development of Detect & Avoid (DAA) systems for remotely piloted aircraft (RPAS), current results are mainly related to systems that only consider air traffic (i.e. other aircraft) hazards. This limitation is currently mitigated by reducing the operation of such DAA systems to an altitude well above the ground and by relying on the remote pilot intervention in case other path constraints can influence correctness of DAA system indications. This paper proposes a new concept of assessing the possible threats for the flight of a RPAS in hazardous scenarios characterized by obstacles of different kinds. Moreover, a strategy for generating an optimal and robust avoidance maneuver that simultaneously considers all such hazards while not causing secondary conflicts is described. Eventually, the proposed DAA system is able to support the remote pilot or perform automatic avoidance maneuvers that take simultaneously into account air traffic, no-fly zones, terrain, bad weather and geo-fencing constraints, thus exceeding current DAA designs. The effectiveness of the proposed algorithm has been demonstrated by means of numerical simulations in several scenarios that are representative of the new features herein described.