The effects of limited intent information availability on self-separation in mixed operations

Abstract

This paper presents the results of a computer simulation of the NASA Autonomous Flight Rules (AFR) concept for airborne self-separation in airspace shared with conventional Instrument Flight Rules (IFR) traffic. This study was designed to determine the impact of varying levels of intent information from IFR aircraft on the performance of AFR conflict detection and resolution. The study used Automatic Dependent Surveillance-Broadcast (ADS-B) to supply IFR intent, but other methods such as an uplink from a ground-based System Wide Information Management (SWIM) network could alternatively supply this information. The independent variables of the study consist of the number of ADS-B trajectory change reports broadcast by IFR aircraft and the time interval between those reports. The conflict detection and resolution metrics include: the number of conflicts and losses of separation, the average conflict warning time, and the amount of time spent in strategic vs. tactical flight modes (i.e., whether the autoflight system was decoupled from the planned route in the Flight Management System in order to respond to a short-notice traffic conflict). The results show a measurable benefit of broadcasting IFR intent vs. relying on state-only broadcasts. The results of this study will inform ongoing separation assurance research and FAA NextGen design decisions for the sharing of trajectory intent information in the National Airspace System.

Analysis of Traffic Conflicts in a Mixed-Airspace Evaluation of Airborne Separation Assurance

“…Beyond the mandated ADS-B state vector, AOP has been designed to incorporate information such as the target state report and trajectory change points into its conflict detection process. This experiment 3 and previous work 7 have shown the dramatic value of a small amount of near-term trajectory intent on the performance of AOP's conflict detection algorithms. Within AOP's current design, the availability of this information reduces the number of conflicts overall as well as the required amount of higher-workload tactical maneuvering.…”