Airports are being developed and expanded rapidly in China to accommodate and promote a growing aviation market.The future Beijing Daxing International Airport（DAX） will serve as the central airport of the JingJinJi...Airports are being developed and expanded rapidly in China to accommodate and promote a growing aviation market.The future Beijing Daxing International Airport（DAX） will serve as the central airport of the JingJinJi megaregion,knitting the Beijing,Tianjin,and Hebei regions together.DAX will be a busy airport from its inception,relieving congestion and accommodating growth from Beijing Capital International Airport（PEK）,currently the second busiest airport in the world in passengers moved.We aim to model terminal airspace designs and possible conflicts in the future Beijing Multi-Airport System（MAS）.We investigate standard arrival procedures and mathematically model current and future arrival trajectories into PEK and DAX by collecting large quantities of publicly available track data from historical arrivals operating within the Beijing terminal airspace.We find that（1） trajectory models constructed from real data capture aberrations and deviations from standard arrival procedures,validating the need to incorporate data on historical trajectories with standard procedures when evaluating the airspace and（2） given all existing constraints,DAX may be restricted to using north and east arrival flows,constraining the capacity required to handle the increases in air traffic demand to Beijing.The results indicate that the terminal airspace above Beijing,and the future JingJinJi region,requires careful consideration if the full capacity benefits of the two major airports are to be realized.展开更多
Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft...Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft rendezvous and docking terminal phase with external disturbance is investigated in this paper.Firstly,a fixed-time observer based on real-time differentiator is developed to compensate for the external disturbance,whose estimation error can converge to zero after a time independent of the initial state.Then,a sliding surface ensuring fixed-time convergence is presented.This sliding surface can guarantee that the vehicle achieves a non-concave trajectory,which is better for avoiding collision and maintaining the visibility of the landing site or docking port.Next,the nonsingular guidance ensuring the fixed-time convergence of the sliding surface is proposed,which is continuous and chatter free.At last,three numerical simulations of Mars landing are performed to validate the effectiveness and correctness of the designed scheme.展开更多
终端区航空器的飞行密度和复杂度较高,此管制区域的处理能力是制约航空体系效率的瓶颈,对进场航空器管制效率进行量化研究,有助于提高管制工作处理能力和质量。首先,提出以区域导航(RNAV,regional area navigation)标准仪表进场程序的...终端区航空器的飞行密度和复杂度较高,此管制区域的处理能力是制约航空体系效率的瓶颈,对进场航空器管制效率进行量化研究,有助于提高管制工作处理能力和质量。首先,提出以区域导航(RNAV,regional area navigation)标准仪表进场程序的标称里程为计算基准量化进场管制效率,通过随机搜索聚类算法的结果得到航空器使用的RNAV标准仪表进场程序,选用在北京首都国际机场着陆的航空器为分析对象,计算航空器的进场管制效率,结合航迹讨论不同RNAV标准仪表进场程序下航空器的运行方式及特点。其次,对进场管制效率的影响因素进行分析,并采用灰色关联分析法量化各影响因素的影响程度与权重,结果显示:雷达引导度和航行三要素改变次数对进场管制效率具有显著影响,飞行流量和RNAV标准仪表进场程序的标称里程对进场管制效率的影响相对较小。继而,从影响因素角度出发评估整体进场管制效率,得到更为全面客观的整体进场管制效率。最后,尝试从RNAV进场程序路径以及优良管制行为模式两方面寻求进场管制效率的提升途径和方法。展开更多
文摘Airports are being developed and expanded rapidly in China to accommodate and promote a growing aviation market.The future Beijing Daxing International Airport（DAX） will serve as the central airport of the JingJinJi megaregion,knitting the Beijing,Tianjin,and Hebei regions together.DAX will be a busy airport from its inception,relieving congestion and accommodating growth from Beijing Capital International Airport（PEK）,currently the second busiest airport in the world in passengers moved.We aim to model terminal airspace designs and possible conflicts in the future Beijing Multi-Airport System（MAS）.We investigate standard arrival procedures and mathematically model current and future arrival trajectories into PEK and DAX by collecting large quantities of publicly available track data from historical arrivals operating within the Beijing terminal airspace.We find that（1） trajectory models constructed from real data capture aberrations and deviations from standard arrival procedures,validating the need to incorporate data on historical trajectories with standard procedures when evaluating the airspace and（2） given all existing constraints,DAX may be restricted to using north and east arrival flows,constraining the capacity required to handle the increases in air traffic demand to Beijing.The results indicate that the terminal airspace above Beijing,and the future JingJinJi region,requires careful consideration if the full capacity benefits of the two major airports are to be realized.
基金co-supported by the National Defense Basic Scientific Research Project,China(No.JCKY2020903B002)the National Natural Science Foundation of China(Nos.61973100,62273118 and 12150008)。
文摘Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft rendezvous and docking terminal phase with external disturbance is investigated in this paper.Firstly,a fixed-time observer based on real-time differentiator is developed to compensate for the external disturbance,whose estimation error can converge to zero after a time independent of the initial state.Then,a sliding surface ensuring fixed-time convergence is presented.This sliding surface can guarantee that the vehicle achieves a non-concave trajectory,which is better for avoiding collision and maintaining the visibility of the landing site or docking port.Next,the nonsingular guidance ensuring the fixed-time convergence of the sliding surface is proposed,which is continuous and chatter free.At last,three numerical simulations of Mars landing are performed to validate the effectiveness and correctness of the designed scheme.
文摘终端区航空器的飞行密度和复杂度较高,此管制区域的处理能力是制约航空体系效率的瓶颈,对进场航空器管制效率进行量化研究,有助于提高管制工作处理能力和质量。首先,提出以区域导航(RNAV,regional area navigation)标准仪表进场程序的标称里程为计算基准量化进场管制效率,通过随机搜索聚类算法的结果得到航空器使用的RNAV标准仪表进场程序,选用在北京首都国际机场着陆的航空器为分析对象,计算航空器的进场管制效率,结合航迹讨论不同RNAV标准仪表进场程序下航空器的运行方式及特点。其次,对进场管制效率的影响因素进行分析,并采用灰色关联分析法量化各影响因素的影响程度与权重,结果显示:雷达引导度和航行三要素改变次数对进场管制效率具有显著影响,飞行流量和RNAV标准仪表进场程序的标称里程对进场管制效率的影响相对较小。继而,从影响因素角度出发评估整体进场管制效率,得到更为全面客观的整体进场管制效率。最后,尝试从RNAV进场程序路径以及优良管制行为模式两方面寻求进场管制效率的提升途径和方法。
