Towards a Feasible Design Space for Proximity Alerts Between Two Aircraft in the Conflict Plane

Abstract

In studying airspace it is necessary to have a model of how and when two aircraft come into proximity. There are two components: a kinematic description of the aircraft in flight, and a set of rules for deciding whether proximity has occurred. The focus in this paper is on the rules with the kinematics kept as simple as possible by utilizing the crossing track model. The aircraft are assumed to be flying straight-line paths at constant speed in a common plane towards a common waypoint A where the paths intersect. The kinematics is completely determined once the initial positions and the velocity vectors are known. A set of proximity rules are described which then permit partitioning of a constrained mathematical model for proximity. The partitioning is a function of parameter values derived from the proximity rules. It follows that the region where all constraints are satisfied defines a Feasible Design Space (FDS), and a different set of design variables is identified for describing the kinematics than is commonly used in current practice. The Compromise Decision Support methodology constructs permit the formalization of the analysis of how different designs for airspace management and communication might affect the occurrence of proximity between aircraft. The existence of proximity can be determined analytically once the kinematic variables are known. The use of the new FDS is applicable hierarchically from strategic planning through to real-time adaption required in actual in-flight operations. It is important as a visualization tool for simulation studies and decision support analyses.