Abstract:A closed loop control approach was proposed to overcome the shortcomings of open loop control that can not tackle stochastic events in airport surface operations. A control strategy for head-on conflict on taxiway in an airport equipped with an A-SMGCS (advanced surface movement guidance and control system) was investigated based on the supervisory control theory of DES (discrete event systems). A controlled Petri net model for the taxiway layout was established, which maps the set of places to the set of taxiing routes. The model was simplified using the known taxiing routes sequences of aircrafts. The sufficient and necessary conditions to avoid head-on conflict on taxiway were determined with the loops and loop chain being considered. Conflict avoidance strategies and the corresponding algorithm for decision-making were presented. Simulation demonstrated that the proposed strategy could identify and avoid head-on conflict on taxiway in real time by monitoring the surface operations.