Conflict Resolution for Wake Encounter Prevention

Abstract

The present report is the deliverable D3.3-3 for the subcontract SubWEPS. In the frame of this subcontract several subsystems of the Airbus Wake Encounter Prevention System (WEPS) are to be further developed by DLR. In task 3.3, for which this report acts as deliverable, the conflict resolution algorithms are to be developed. This report gives a detailed description of the applied methodology for conflict resolution, the algorithm design and implementation, as well as the verification results to show that the algo-rithms work properly. The chosen method is a motion / path primitive method, which comprises many advantages for evasion trajectory generation of a fixed-wing aircraft, namely an inherently given flyability of the trajectory without any necessary post-processing for trajectory smoothing and the easy consideration of passenger comfort criteria. The algorithm builds a tree structure comprising all possible paths which neither violate any of the navigational restraints, the wake habitation area, nor ground, nor traffic collision avoidance constraints. Each of the path tree nodes is rated with a specific cost value, which is summed along the full trajectory. In order to allow a rating of the possibly remaining cost for each node to a specific goal node the cost func-tion comprises a heuristic part. The decision whether the evasive manoeuvre should be per-formed vertically or laterally is made by means of the encounter geometry. The verification showed that the algorithm is well able to handle various conflict situations with vertical and lateral evasion. The developed conflict resolution software was tested without obstacles and with single and multiple, fixed and moving obstacles at different positions.