A high-precision nominal flight profile,involving controllers′intentions is critical for 4Dtrajectory estimation in modern automatic air traffic control systems.We proposed a novel method to effectively improve the a...A high-precision nominal flight profile,involving controllers′intentions is critical for 4Dtrajectory estimation in modern automatic air traffic control systems.We proposed a novel method to effectively improve the accuracy of the nominal flight profile,including the nominal altitude profile and the speed profile.First,considering the characteristics of trajectory data,we developed an improved K-means algorithm.The approach was to measure the similarity between different altitude profiles by integrating the space warp edit distance algorithm,thereby to acquire several fitted nominal flight altitude profiles.This approach breaks the constraints of traditional K-means algorithms.Second,to eliminate the influence of meteorological factors,we introduced historical gridded binary data to determine the en-route wind speed and temperature via inverse distance weighted interpolation.Finally,we facilitated the true airspeed determined by speed triangle relationships and the calibrated airspeed determined by aircraft data model to extract a more accurate nominal speed profile from each cluster,therefore we could describe the airspeed profiles above and below the airspeed transition altitude,respectively.Our experimental results showed that the proposed method could obtain a highly accurate nominal flight profile,which reflects the actual aircraft flight status.展开更多
A new Kinetic Energy Rod( KER) warhead named profiled rod warhead is proposed in this paper.Based on the design of profiled rod warhead,a model of profiled rod driven by detonation is established. The detonation proce...A new Kinetic Energy Rod( KER) warhead named profiled rod warhead is proposed in this paper.Based on the design of profiled rod warhead,a model of profiled rod driven by detonation is established. The detonation process is simulated by ANSYS / LS-DYNA,and the deployment velocity and initial flight attitude of rod are achieved. In addition,static rod deployment testing are performed to investigate the damage effect,the spatial flight attitude and deployment velocity. A satisfactory agreement is obtained by the comparison between numerical results and testing results. Meanwhile,the profiled rod studies are conducted to determine a higher penetrability compared with traditional cylindrical rods. Rigid body dynamics equations of profiled rod,which accounts for the influence of air resistance,are set up to predict the flight trajectory of long-distance. The results show that the profiled rod may provide a better penetration angle which still maintains a significant penetrability against projectiles when the rods move off long-distance range.展开更多
通过应用电动垂直起降(electric vertical take-off and landing,简称eVTOL)飞行器可实现零排放的短途快速城市空中出行,缓解地面交通拥堵的问题。但城市地区密集的人口以及eVTOL高度的自动化等因素给飞行安全性也带来了诸多挑战。基于...通过应用电动垂直起降(electric vertical take-off and landing,简称eVTOL)飞行器可实现零排放的短途快速城市空中出行,缓解地面交通拥堵的问题。但城市地区密集的人口以及eVTOL高度的自动化等因素给飞行安全性也带来了诸多挑战。基于局方对于eVTOL设立的顶层安全性目标,分析了当严重失效发生时,eVTOL飞机级安全性减缓措施——抗坠撞性和整机降落伞两种方式的应用限制与效果。通过对减缓措施的对比分析,提出了一种考虑减缓效果的eVTOL飞行任务剖面,并总结出不同飞行阶段的飞机级安全性影响,得出定量的飞行区域关键高度数值。针对飞行剖面中的高风险区域,提出了降低严重失效概率的预防措施,为eVTOL的安全性设计以及适航管理提供参考。展开更多
由于飞行剖面识别是航空器四维(Four-dimensional,4D)航迹预测研究的热点问题,提出一种基于航空器气象资料下传(Aircraft meteorological data relay,AMDAR)数据的全飞行过程剖面生成方法,包括由高度-航程构成的标称高度剖面和空速-航...由于飞行剖面识别是航空器四维(Four-dimensional,4D)航迹预测研究的热点问题,提出一种基于航空器气象资料下传(Aircraft meteorological data relay,AMDAR)数据的全飞行过程剖面生成方法,包括由高度-航程构成的标称高度剖面和空速-航程构成的标称速度剖面。首次将动态空间规整算法(Dynamic space warping,DSW)应用到飞行高度剖面的相似距离计算中,计算出标称飞行高度剖面;为解决在地速未知情况下标称速度剖面的计算问题,结合大椭圆距离算法与航空器基本性能数据库(Base of aircraft data,BADA),给出一种标称飞行速度剖面的计算方法,该方法保留了AMDAR实测历史数据中所隐含的飞行意图与气象因素。实际算例表明,本文提出的方法能够有效地得到真实反映航空器飞行状态的全飞行剖面。展开更多
基金supported by the National Natural Science Foundation of China(Nos.61174180,U1433125)the Jiangsu Province Science Foundation (No.BK20141413)the Chinese Postdoctoral Science Foundation (No.2014M550291)
文摘A high-precision nominal flight profile,involving controllers′intentions is critical for 4Dtrajectory estimation in modern automatic air traffic control systems.We proposed a novel method to effectively improve the accuracy of the nominal flight profile,including the nominal altitude profile and the speed profile.First,considering the characteristics of trajectory data,we developed an improved K-means algorithm.The approach was to measure the similarity between different altitude profiles by integrating the space warp edit distance algorithm,thereby to acquire several fitted nominal flight altitude profiles.This approach breaks the constraints of traditional K-means algorithms.Second,to eliminate the influence of meteorological factors,we introduced historical gridded binary data to determine the en-route wind speed and temperature via inverse distance weighted interpolation.Finally,we facilitated the true airspeed determined by speed triangle relationships and the calibrated airspeed determined by aircraft data model to extract a more accurate nominal speed profile from each cluster,therefore we could describe the airspeed profiles above and below the airspeed transition altitude,respectively.Our experimental results showed that the proposed method could obtain a highly accurate nominal flight profile,which reflects the actual aircraft flight status.
基金Sponsored by the CALT University Joint Fund(Grant No.CALT201105)
文摘A new Kinetic Energy Rod( KER) warhead named profiled rod warhead is proposed in this paper.Based on the design of profiled rod warhead,a model of profiled rod driven by detonation is established. The detonation process is simulated by ANSYS / LS-DYNA,and the deployment velocity and initial flight attitude of rod are achieved. In addition,static rod deployment testing are performed to investigate the damage effect,the spatial flight attitude and deployment velocity. A satisfactory agreement is obtained by the comparison between numerical results and testing results. Meanwhile,the profiled rod studies are conducted to determine a higher penetrability compared with traditional cylindrical rods. Rigid body dynamics equations of profiled rod,which accounts for the influence of air resistance,are set up to predict the flight trajectory of long-distance. The results show that the profiled rod may provide a better penetration angle which still maintains a significant penetrability against projectiles when the rods move off long-distance range.
文摘通过应用电动垂直起降(electric vertical take-off and landing,简称eVTOL)飞行器可实现零排放的短途快速城市空中出行,缓解地面交通拥堵的问题。但城市地区密集的人口以及eVTOL高度的自动化等因素给飞行安全性也带来了诸多挑战。基于局方对于eVTOL设立的顶层安全性目标,分析了当严重失效发生时,eVTOL飞机级安全性减缓措施——抗坠撞性和整机降落伞两种方式的应用限制与效果。通过对减缓措施的对比分析,提出了一种考虑减缓效果的eVTOL飞行任务剖面,并总结出不同飞行阶段的飞机级安全性影响,得出定量的飞行区域关键高度数值。针对飞行剖面中的高风险区域,提出了降低严重失效概率的预防措施,为eVTOL的安全性设计以及适航管理提供参考。
文摘由于飞行剖面识别是航空器四维(Four-dimensional,4D)航迹预测研究的热点问题,提出一种基于航空器气象资料下传(Aircraft meteorological data relay,AMDAR)数据的全飞行过程剖面生成方法,包括由高度-航程构成的标称高度剖面和空速-航程构成的标称速度剖面。首次将动态空间规整算法(Dynamic space warping,DSW)应用到飞行高度剖面的相似距离计算中,计算出标称飞行高度剖面;为解决在地速未知情况下标称速度剖面的计算问题,结合大椭圆距离算法与航空器基本性能数据库(Base of aircraft data,BADA),给出一种标称飞行速度剖面的计算方法,该方法保留了AMDAR实测历史数据中所隐含的飞行意图与气象因素。实际算例表明,本文提出的方法能够有效地得到真实反映航空器飞行状态的全飞行剖面。
