General Aviation Flight Conformance Assessment And Prediction Considering Tolerance

China's general aviation industry is thriving.With airspace resources become tighter,general aviation flight safety is a great challenge.There is inevitable deviation between the actual trajectory and its assigned trajectory.The main cause is general aviation lacks high-precision flight control equipment.Flight conformance assessment is an objective evaluation of the difference between the actual flight trajectory and its designated flight plan,and it is a critical part of the flight operation safety.In order to provide safety tolerance margin for actual general aviation flight activities,flight conformance assessment and prediction considering tolerance is studied.The common distance-based evaluation methods transform the weighting of time,speed and other factors into distance,then use the fixed threshold of sequential track point pairs to evaluate conformance.The calculation is relatively simple,but the robustness is restricted.So flight conformance assessment and prediction considering distance tolerance is proposed.DTW(Dynamic Time Warping)algorithm achieves the adaptive matching of the actual trajectory and its assigned trajectory.It equals introducing distance tolerance and improves the robustness of the fixed threshold evaluation.The experiment with actual flight data demonstrate that the fixed threshold of adaptive point pairs matching is more stable and rational than the fixed threshold of sequential track point pairs.The conformance status changes cannot be effectively identified by the above distance-based evaluation method,especially during the maneuvering phases of a flight.A reasonable time deviation in actual flight operations and its impact are studied.A flight conformance assessment method considering time tolerance is proposed.The fly-by turning is studied as the case of maneuvering scenario.By using the Monte Carlo method,the position of the aircraft during the turn based on the initial turning time distribution,while considering operation tolerance in the time domain,is obtained.The proposed method had been applied to real flight trajectories for demonstrating its effectiveness.Abnormal turning status can be effectively warned in the early stage of turning by the proposed method,compared with that the previous methods using predetermined fixed threshold can only detect actual violations under the same level of accuracy.