A unified approach to separation assurance and collision avoidance for flight management systems

The introduction of dedicated software functions for separation assurance and collision avoidance in Next Generation Flight Management Systems (NG-FMS) has the potential to enable significant advances in the Unmanned Aircraft System (UAS) Traffic Management (UTM) operational context. In this paper, key elements of the NG-FMS architecture are presented that allow planning and optimisation of 4-dimensional trajectories. The NG-FMS is designed to be fully interoperable with a future ground based 4DT Planning, Negotiation and Validation (4-PNV) system, enabling automated Trajectory/Intent-Based Operations (TBO/IBO). This paper addresses one of the key technological challenges for integrating UAS in non-segregated airspace by implementing suitable hardware and software (data fusion) techniques for cooperative and non-cooperative separation assurance and collision avoidance tasks. The sensor/system providing the most reliable separation maintenance and collision avoidance solution is automatically selected and this approach provides robustness in all flight phases supporting all-weather and trusted autonomous operations. The mathematical algorithms employed in the unified approach to cooperative and non-cooperative separation assurance and collision avoidance scenarios are presented. In this method, navigation and tracking errors affecting the host platform and intruder sensor measurements are translated to unified range and bearing uncertainty descriptors. Simulation case studies are presented, including UTM elements such as dynamic geo-fencing, and the results corroborate the validity of separation assurance and collision avoidance algorithms for the considered mission- and safety-critical tasks.