Effect of conflict resolution maneuver execution delay on losses of separation

Cone, Andrew C.

doi:10.1109/dasc.2010.5655379

Cited by 5 publications

(5 citation statements)

References 8 publications

(11 reference statements)

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“…The magnitude of the maneuver that is needed to prevent a loss of separation will increase with a decrease in time until loss of separation. In [2] it is illustrated that the likelihood of triggering another conflict increases with an increase in magnitude of the conflict prevention maneuver, hence it makes sense to not postpone a maneuver until the loss of separation is imminent.…”

Section: Maneuver Selection Timing and Uncertaintymentioning

confidence: 98%

“…However, with the separation margins envisioned in NextGen, a deviation from a 4-D trajectory can result in a loss of separation within a time that is shorter than the time needed to resolve the conflict through trajectory negotiation. Results from recent research performed at NASA Ames [2] indicate that the possibility to use a trajectory-based approach to solve a conflict is limited to about three minutes before the actual conflict occurs. Hence, depending upon the available time until loss of separation on the current trajectory will occur, the pilots will either need to negotiate a new 4-D trajectory or, if insufficient time is available, execute maneuvers 1 to prevent the conflict from occurring without triggering another one.…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Navigation system autonomy and integration in NextGen: Challenges and solutions

Theunissen

Rademaker

Lambregts

2011

2011 IEEE/AIAA 30th Digital Avionics Systems Conference

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For strategic air traffic management, NextGen foresees the use of negotiated 4-D trajectories. With the separation margins envisioned in NextGen, navigation errors can result in a loss of separation within a time that is shorter than the time needed to resolve the conflict through trajectory negotiation. A gap exists between the time to conflict that the situation can be resolved through trajectory negotiation and the time to conflict at which TCAS starts to provide collision avoidance guidance. To limit the situations in which TCAS must provide collision avoidance guidance, the challenge is to minimize the encounter probability in the time domain where negotiating 4-D solutions is not practical. To support the pilot with self-separation, ADS-B enabled Conflict Detection and Resolution (CD&R) concepts are being developed. To realize a situation in which the pilot assesses options generated by the CD&R system and selects the one to be executed by the GNC system, integration between these two systems is required. The integration needs to address the autonomy of the system functions, the associated role of the pilot and the resulting information requirements. The work discussed in this paper has focused on the design of a concept for the computation and execution of conflict prevention maneuvers with a high degree of trajectory (outerloop) predictability and the presentation of the result to the pilot in such a way that it can be used both for manual and supervisory control. The basis for this approach is the use of conflict probes for the CD&R function. Based on the location and extent of the predicted conflict space(s), a set of trajectories are continuously computed and presented to the pilot. The pilot can assess the different trajectories relative to the constraints and select the most appropriate one. A number of examples are provided to illustrate the concept.

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Section: Maneuver Selection Timing and Uncertaintymentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Navigation system autonomy and integration in NextGen: Challenges and solutions

Theunissen

Rademaker

Lambregts

2011

2011 IEEE/AIAA 30th Digital Avionics Systems Conference

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“…Examples of related work on secondary conflicts include the following: In [11], the potential reoccurrence of a primary conflict or occurrence of a secondary conflict due to delay in execution of a resolution maneuver was investigated. The analysis was conducted using the Airspace Concept Evaluation System (ACES) simulation tool.…”

Section: Introductionmentioning

confidence: 99%

A methodology for estimating the probability of potential secondary conflicts

Shortle¹,

Belle²

2013

2013 IEEE/AIAA 32nd Digital Avionics Systems Conference (DASC)

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In a distributed separation assurance system, each aircraft is equipped with its own conflict detection and resolution capability. An aircraft that is resolving an initial primary conflict has complete state information of all nearby aircraft, so is able to choose a resolution trajectory that is conflict-free from all other aircraft. However, because the update of state information is not instantaneous, it is possible that two distinct conflicts, if resolved in a nearsimultaneous manner, may result in a downstream secondary conflict. Also an intent error in the state information may lead to a potential secondary conflict. This paper presents a methodology and sample results to analyze the frequency of potential secondary conflicts using output from a NAS-wide simulation. The events considered are not secondary conflicts themselves, but rather potential secondary conflicts, or situations in which there is an increased likelihood of a secondary conflict.

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“…Some examples include studies examining enlarged horizontal detection ranges in the presence of cruise speed errors, 10 wind prediction errors, 11 and maneuver-initiation time errors. 12 One common theme through much of this work is a primary focus on horizontal errors and the effectiveness of using horizontal buffers or probabilistic conflict detection schemes to account for those errors. Some simulation test beds, such as the Center-TRACON Automation System (CTAS) 13 use a vertical buffer for aircraft that are transitioning altitudes, but that buffer is often on the order of hundreds of feet, which is not enough to account for uncertainties during the descent phase.…”

Section: Introductionmentioning

confidence: 99%

Robust Conflict Detection and Resolution around Top of Descent

Cone

Bowe

Lauderdale

2012

12th AIAA Aviation Technology, Integration, and Operations (ATIO) Conference and 14th AIAA/ISSMO Multidisciplinary Analysis And

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One of the complicating factors when detecting and resolving aircraft-to-aircraft conflicts is trajectory prediction uncertainty, which can cause conflicts to be detected without sufficient time to resolve them. Previous work by the authors showed this situation occurs most often in Center Airspace when an aircraft is between about 10 nmi before its top-ofdescent point and its arrival fix at the edge of the terminal area. This paper explores a pair of enhanced vertical conflict detection ranges (buffers) for aircraft descending to their meter fix that could provide enough coverage to catch potential losses for multiple types of uncertainty while limiting the increase in false alerts. The specific uncertainties examined include the predicted wind speed, cruise speed, descent speed, top-of-descent location, and the combination of all of those uncertainties plus uncertainty in aircraft fuel weight prediction. Performance metrics include false alerts, missed alerts, losses of separation, number of resolutions issued, and the total system delay caused by aircraft flying conflict avoidance maneuvers. Results show that these vertical buffers reduce the number of losses of separation for arriving aircraft from 207 to 12. However, using the vertical buffers increases the number of resolutions issued by 50% and doubles the delay accrued by aircraft flying conflict resolution maneuvers. Results also suggest that a smaller buffer (80% size) could be used to gain most of the same benefit as the full buffer with less additional delay, while alternative methods might be best suited to remove the last few loss of separation cases during descent. Further, improving the trajectory prediction accuracy combined with a vertical buffer significantly reduced the number of losses of separation, resolutions issued, and delay accrued.

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Effect of conflict resolution maneuver execution delay on losses of separation

Cited by 5 publications

References 8 publications

Navigation system autonomy and integration in NextGen: Challenges and solutions

Navigation system autonomy and integration in NextGen: Challenges and solutions

A methodology for estimating the probability of potential secondary conflicts

Robust Conflict Detection and Resolution around Top of Descent

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