Publications
Correlated Bayesian model of aircraft encounters in the terminal area given a straight takeoff or landing
March 12, 2022
Journal Article
Published in:
Aerospace, Vol. 9, No.2, 12 March 2022.
Summary
The integration of new airspace entrants into terminal operations requires design and evaluation of Detect and Avoid systems that prevent loss of well clear from and collision with other aircraft. Prior to standardization or deployment, an analysis of the safety performance of those systems is required. This type of analysis has typically been conducted by Monte Carlo simulation with synthetic, statistically representative encounters between aircraft drawn from an appropriate encounter model. While existing encounter models include terminal airspace classes, none explicitly represents the structure expected while engaged in terminal operations, e.g., aircraft in a traffic pattern. The work described herein is an initial model of such operations where an aircraft landing or taking off via a straight trajectory encounters another aircraft landing or taking off, or transiting by any means. The model shares the Bayesian network foundation of other Massachusetts Institute of Technology Lincoln Laboratory encounter models but tailors those networks to address structured terminal operations, i.e., correlations between trajectories and the airfield and each other. This initial model release is intended to elicit feedback from the standards-writing community.
Summary
The integration of new airspace entrants into terminal operations requires design and evaluation of Detect and Avoid systems that prevent loss of well clear from and collision with other aircraft. Prior to standardization or deployment, an analysis of the safety performance of those systems is required. This type of analysis...
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Benchmarking the processing of aircraft tracks with triples mode and self-scheduling
September 20, 2021
Conference Paper
Published in:
2021 IEEE High Performance Extreme Computing Conf., HPEC, 20-24 September 2021.
Summary
As unmanned aircraft systems (UASs) continue to integrate into the U.S. National Airspace System (NAS), there is a need to quantify the risk of airborne collisions between unmanned and manned aircraft to support regulation and standards development. Developing and certifying collision avoidance systems often rely on the extensive use of Monte Carlo collision risk analysis simulations using probabilistic models of aircraft flight. To train these models, high performance computing resources are required. We've prototyped a high performance computing workflow designed and deployed on the Lincoln Laboratory Supercomputing Center to process billions of observations of aircraft. However, the prototype has various computational and storage bottlenecks that limited rapid or more comprehensive analyses and models. In response, we've developed a novel workflow to take advantage of various job launch and task distribution technologies to improve performance. The workflow was benchmarked using two datasets of observations of aircraft, including a new dataset focused on the environment around aerodromes. Optimizing how the workflow was parallelized drastically reduced the execution time from weeks to days.
Summary
As unmanned aircraft systems (UASs) continue to integrate into the U.S. National Airspace System (NAS), there is a need to quantify the risk of airborne collisions between unmanned and manned aircraft to support regulation and standards development. Developing and certifying collision avoidance systems often rely on the extensive use of...
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NASA Airspace Integration Detect and Avoid Phase 2: Safety Risk Management Simulation Plan
December 18, 2020
Project Report
Published in:
MIT Lincoln Laboratory Report
Summary
RTCA has been developing Minimum Operational Performance Standards (MOPS) for Detect and Avoid (DAA) and Command and Control (C2) systems as part of Special Committee – 228 (SC-228). The Phase 1 MOPS were published in 2017 and a Phase 2 effort to revise and extend the Phase 1 MOPS is ongoing. In order for the MOPS to be fully utilized, they must be evaluated by the FAA employing the FAA's Safety Risk Management (SRM) process. In order to support the SRM process, there is a need for simulation data focused on the safety of DAA encounters. This analysis focuses on gathering information to validate the use of SC-228 MOPS compliant DAA and C2 systems to enable routine UAS operations in the National Airspace System (NAS) without a chase aircraft or visual observers. The scope of this effort aligns with the SC-228 Terms of Reference (TOR) that can be generally characterized as UAS flying IFR and receiving ATC separation services. This analysis evaluates the system safety in mixed classes B, C, D, E, and G airspaces, and includes IFR, VFR, Cooperative, and Non-Cooperative aircraft. This analysis plan describes the four analysis tasks (Section 2) and the simulation plan (Section 3) that will be executed to accomplish these tasks. It is expected that this analysis plan will be extended to include the analysis results and become the final deliverable.
Summary
RTCA has been developing Minimum Operational Performance Standards (MOPS) for Detect and Avoid (DAA) and Command and Control (C2) systems as part of Special Committee – 228 (SC-228). The Phase 1 MOPS were published in 2017 and a Phase 2 effort to revise and extend the Phase 1 MOPS is...
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Detect-and-avoid closed-loop evaluation of noncooperative well clear definitions
July 12, 2020
Journal Article
Published in:
J. Air Transp., Vol. 28, No. 4, 12 July 2020, pp. 195-206.
Summary
Four candidate detect-and-avoid well clear definitions for unmanned aircraft systems encountering noncooperative aircraft are evaluated using safety and operational suitability metrics. These candidates were proposed in previous research based on unmitigated collision risk, maneuver initiation ranges, and other considerations. Noncooperative aircraft refer to aircraft without a functioning transponder. One million encounters representative of the assumed operational environment for the detect-and-avoid system are simulated using a benchmark alerting and guidance algorithm as well as a pilot response model. Results demonstrate sensitivity of the safety metrics to the unmanned aircraft’s speed and the detect-and-avoid system's surveillance volume. The only candidate without a horizontal time threshold, named modified tau, outperforms the other three candidates in avoiding losses of detect and avoid well clear. Furthermore, this candidate's alerting timeline lowers the required surveillance range. This can help reduce the barrier of enabling unmanned aircraft systems' operations with low size, weight, and power sensors.
Summary
Four candidate detect-and-avoid well clear definitions for unmanned aircraft systems encountering noncooperative aircraft are evaluated using safety and operational suitability metrics. These candidates were proposed in previous research based on unmitigated collision risk, maneuver initiation ranges, and other considerations. Noncooperative aircraft refer to aircraft without a functioning transponder. One million...
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