Merging and Spacing of Heterogeneous Aircraft in Support of NextGen

FAA's NextGen program aims to increase the capacity of the national airspace, while ensuring the safety of aircraft.This paper provides a distributed merging and spacing algorithm that maximizes the throughput at the terminal phase of flight, using information communicated between neighboring aircraft through the ADS-B framework.Aircraft belonging to a mixed fleet negotiate with each other and use dual decomposition to reach an agreement on optimal merging times, with respect to a pairwise cost, while ensuring proper inter-aircraft spacing for the respective aircraft types.A set of sufficient conditions on the geometry and operating conditions of merging forks are provided to identify when proper inter-aircraft spacing can always be achieved using the proposed algorithm for any combination of merging aircraft.Also, optimal decentralized controllers are derived for merging air traffic when operating under such conditions.The performance of the presented algorithm is verified through computer simulations.