Improving short-term conflict alert via tabu search

Beasley, John E.; Howells, Hugh; Sonander, Julia

doi:10.1057/palgrave.jors.2601358

Cited by 6 publications

(11 citation statements)

References 4 publications

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“…As an indication of the increasing complexity it may be noted that since the work of Beasley et al [2] in 2002 the increase in the number of fine filter parameters and regions has led to an increase of roughly 500 in the number of STCA parameters.…”

Section: A Manual Optimisationmentioning

confidence: 99%

“…Beasley et al [2] recognised that the current approach of tweaking the system variables by hand may be suboptimal, and so applied the tabu search heuristic in an attempt to automate the process. In this work a single objective was maximised.…”

Section: B Weighted Objective Optimisationmentioning

confidence: 99%

“…The tabu search optimiser [2] was also found to be susceptible to trapping in local minima and required manual analysis of the parameter space to re-start the search. Perhaps in the light of these considerations, the original iterative person-based adjustment is still in use by NATS.…”

Section: Bad Datamentioning

confidence: 99%

“…The STCA system became operational for part of UK airspace in 1988 [2] and versions capable of coping with complex terminal control airspaces have been in operation since 1994. Since its introduction there have been incremental changes to the software and it is now used across the UK and elsewhere.…”

mentioning

confidence: 99%

“…The great number of parameters (at least 1500) determining the behaviour of STCA make tuning a highly skilled and laborious business. However, despite a recent step towards automation [2], the optimal receiver operating characteristics of the STCA system have not been known.…”

mentioning

confidence: 99%

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Multiobjective optimization of safety related systems: an application to short-term conflict alert

Everson

Fieldsend

2006

IEEE Trans. Evol. Computat.

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Many safety related and critical systems warn of potentially dangerous events; for example, the Short Term Conflict Alert (STCA) system warns of airspace infractions between aircraft. Although installed with current technology such critical systems may become out of date due to changes in the circumstances in which they function, operational procedures and the regulatory environment. Current practice is to 'tune' by hand the many parameters governing the system in order to optimise the operating point in terms of the true positive and false positive rates, which are frequently associated with highly imbalanced costs.In this paper we cast the tuning of critical systems as a multi-objective optimisation problem. We show how a region of the optimal receiver operating characteristic (ROC) curve may be obtained, permitting the system operators to select the operating point. We apply this methodology to the STCA system, using a multi-objective (1+1)-evolution strategy, showing that we can improve upon the current hand-tuned operating point, as well as providing the salient ROC curve describing the true positive versus false positive trade-off. We also provide results for three-objective optimisation of the alert response time in addition to the true and false positive rates. Additionally, we illustrate the use of bootstrapping for representing evaluation uncertainty on estimated Pareto fronts, where the evaluation of a system is based upon a finite set of representative data.

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Section: A Manual Optimisationmentioning

confidence: 99%

Section: B Weighted Objective Optimisationmentioning

confidence: 99%

Section: Bad Datamentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Multiobjective optimization of safety related systems: an application to short-term conflict alert

Everson

Fieldsend

2006

IEEE Trans. Evol. Computat.

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STCA, TCAS, Airproxes and Collision Risk

Brooker¹

2005

J. Navigation

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The focus here is on the performance of and interaction between the Traffic Alert and Collision Avoidance System (TCAS) and the controller's short-term conflict alert (STCA) system. The data source used is UK Airprox Board Reports of close encounters between aircraft, and the focus is on commercial air transport aircraft using UK controlled airspace with a radar service. Do the systems work well together ? Are controllers surprised when they find out that a pilot has received a TCAS resolution advisory? What do TCAS and STCA events say about collision risk ? Generally, the systems seem to work together well. On most occasions, controllers are not surprised by TCAS advisories : either they have detected the problem themselves or STCA has alerted them to it. The statistically expected rate of future mid-air collisions is estimated by extrapolation of Airprox closest encounter distances. K E Y

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Air Traffic Control Separation Minima: Part 2 – Transition to a Trajectory-based System

Brooker

2011

J. Navigation

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Current strategic plans for Air Traffic Management (ATM) envisage a transition from radar control to a trajectory-based system. Part 1 sketched the historical origins of separation minima and then analysed the safety thinking behind current minima and the issues involved in risk modelling. Part 2 examines the future situation. This focuses on the intermediate steps to the final system – upgraded capabilities in a mixed-equipage system. Future traffic mixes two categories of traffic: V aircraft, i.e. vectored traditional ATC-handled, and 4D aircraft, i.e. flying on 4D trajectories. Conflict probe and other decision support tools will need to be in place, inter alia to prevent controller workload from increasing. Conceptually, future risks in the transition period will be the sum of three types of aircraft encounter risk: V/V, 4D/4D and 4D/V. These pose different kinds of problem for ATC, appropriate conflict alerting systems and risk assessment. The numbers of 4D/V encounters increase rapidly with growth in the proportion of 4D aircraft. With reduced minima, airborne collision avoidance systems would be unlikely to resolve higher relative velocity encounters were the ATC system to fail. It would be a difficult decision to reduce markedly ATC separation minima for any category of aircraft encounters during the transition period.

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Improving short-term conflict alert via tabu search

Cited by 6 publications

References 4 publications

Multiobjective optimization of safety related systems: an application to short-term conflict alert

Multiobjective optimization of safety related systems: an application to short-term conflict alert

STCA, TCAS, Airproxes and Collision Risk

Air Traffic Control Separation Minima: Part 2 – Transition to a Trajectory-based System

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