Protocol-Based Conflict Resolution for Air Traffic Control

This paper proposes a simple geometric method for collaborative multiple-aircraft conflict avoidance. We assume that aircraft cruise at constant altitude with varying velocities and thus consider conflict resolution on planar airspace. The multiple-aircraft conflict resolution methodology is presented in two steps; first, we consider an unrealistic but geometrically simple exact conflict, in which the original trajectories of all aircraft intersect at a point, in order to derive a closed-form analytic solution for the required heading change, and then we consider a realistic general conflict, in which conflict points of multiple aircraft do not coincide. Heading change is the main control input for conflict resolution, yet velocity change is also used for a general conflict. The proposed algorithm is based on a protocol, a simple rule for multiple-aircraft conflict resolution, which is easily understandable and implementable by all aircraft involved in the conflict, and provides guarantees of safety within the limits of the model used. We show that this solution is robust to uncertainties in the aircraft’s position, heading, and velocity, as well as to path smoothing, and asynchronous maneuvers. We present simulation results using a dynamic aircraft model for various multiple-aircraft conflict scenarios based on Enhanced Traffic Management System (ETMS) data.