CONFLICT DETECTION AND RESOLUTION IN THE PRESENCE OF PREDICTION ERROR Heinz Erzberger, Russell A. Paielli, Douglas R. Isaacson, and Michelle M. Eshow Abstract This paper describes the design of a conflict detection and resolution tool, referred to as a Conflict Probe, for use by enroute (Center) air traffic controllers. This tool is designed to help detect and resolve all classes of conflicts, such as overflight/ overflight, arrival/ overflight, climbout/ overflight, etc., up to twenty minutes in advance. The design is based on an approach that combines deterministic trajectory prediction and stochastic conflict analysis to achieve reliable conflict detection. The paper begins by formulating error models for trajectory prediction. Then an efficient algorithm is described for estimating conflict probability as a function of encounter geometry. The conflict probability theory and algorithm are applied to the design of the Conflict Probe and are further used to develop a method of automated conflict resolution with constraints on the post-resolution conflict probability. Next, aircraft performance models and equations of motion for generating four-dimensional trajectories are presented. The paper concludes with a description of the methods used to minimize the time to search the trajectories for potential conflicts. Performance tests of the search algorithm indicate that up to 800 aircraft can be processed by the Probe within a search cycle of 10 seconds. The Conflict Probe has been implemented as a software process within the Center- TRACON Automation System (CTAS). It uses the trajectory synthesis capability of CTAS to generate predicted trajectories for the conflict search and trial resolution processes. Field evaluation of the Probe will be conducted at the Denver and Fort Worth Centers beginning in September 1997.