In required navigation performance（RNP）, total system error（TSE） is estimated to provide a timely warning in the presence of an excessive error. In this paper, by analyzing the underlying formation mechanism, the ...In required navigation performance（RNP）, total system error（TSE） is estimated to provide a timely warning in the presence of an excessive error. In this paper, by analyzing the underlying formation mechanism, the TSE estimation is modeled as the estimation fusion of a fixed bias and a Gaussian random variable. To address the challenge of high computational load induced by the accurate numerical method, two efficient methods are proposed for real-time application, which are called the circle tangent ellipse method（CTEM） and the line tangent ellipse method（LTEM）,respectively. Compared with the accurate numerical method and the traditional scalar quantity summation method（SQSM）, the computational load and accuracy of these four methods are extensively analyzed. The theoretical and experimental results both show that the computing time of the LTEM is approximately equal to that of the SQSM, while it is only about 1/30 and 1/6 of that of the numerical method and the CTEM. Moreover, the estimation result of the LTEM is parallel with that of the numerical method, but is more accurate than those of the SQSM and the CTEM. It is illustrated that the LTEM is quite appropriate for real-time TSE estimation in RNP application.展开更多
为评估新设计民用飞机所需导航性能(required navigation performance,RNP)的导航能力,针对直飞(track to fix,TF)航段和固定转弯半径(radius to fix,RF)航段类型,建立了飞行侧向偏差模型和飞行高度偏差模型,通过地理坐标转换,计算飞机...为评估新设计民用飞机所需导航性能(required navigation performance,RNP)的导航能力,针对直飞(track to fix,TF)航段和固定转弯半径(radius to fix,RF)航段类型,建立了飞行侧向偏差模型和飞行高度偏差模型,通过地理坐标转换,计算飞机实际飞行航迹与定义航径之间的偏差。以某新民用飞机的一次飞行为例,选取某机场进近的飞行数据进行计算,对飞行偏差进行统计,分析该飞机的适航情况及所对应的导航能力。结果表明,该飞机的基于性能导航(performance based navigation,PBN)的导航精度可满足适航标准中RNP 0.1的要求,机型执行RNP程序的质量达标。展开更多
The sixth generation(6G)mobile network is envisaged to be commercially deployed around 2030,which will profoundly change people's lifestyles and accelerate the digitalization of society.To ensure that the requirem...The sixth generation(6G)mobile network is envisaged to be commercially deployed around 2030,which will profoundly change people's lifestyles and accelerate the digitalization of society.To ensure that the requirements of 6G can be achieved,it is essential to establish a set of key performance indicators(KPIs).This paper comprehensively assesses the KPIs not only from the service requirements but also from the technical feasibility points of view.Specifically,theoretical derivations of KPIs have been clarified,and numerical evaluations have been conducted with reasonable technical assumptions.Evaluation results show that some KPIs defined from the service requirements can be improved through advanced technologies while some are still challenging for practical implementations,such as Tbps-level peak data rate and 0.1 ms user plane latency.In addition,it is also necessary to comply with multiple KPIs for some cases.Furthermore,based on the technical analysis,the potential enabling technologies are outlined and foreseeable implementation challenges as well as possible solutions are presented,which promotes a more reasonable design for 6G mobile network.展开更多
基金supported by the National Basic Research Program of China (No. 2010CB731805)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No. 60921001)the Special Fund for Basic Research on Scientific Instruments of China (No. 2011YQ04008301)
文摘In required navigation performance（RNP）, total system error（TSE） is estimated to provide a timely warning in the presence of an excessive error. In this paper, by analyzing the underlying formation mechanism, the TSE estimation is modeled as the estimation fusion of a fixed bias and a Gaussian random variable. To address the challenge of high computational load induced by the accurate numerical method, two efficient methods are proposed for real-time application, which are called the circle tangent ellipse method（CTEM） and the line tangent ellipse method（LTEM）,respectively. Compared with the accurate numerical method and the traditional scalar quantity summation method（SQSM）, the computational load and accuracy of these four methods are extensively analyzed. The theoretical and experimental results both show that the computing time of the LTEM is approximately equal to that of the SQSM, while it is only about 1/30 and 1/6 of that of the numerical method and the CTEM. Moreover, the estimation result of the LTEM is parallel with that of the numerical method, but is more accurate than those of the SQSM and the CTEM. It is illustrated that the LTEM is quite appropriate for real-time TSE estimation in RNP application.
文摘为评估新设计民用飞机所需导航性能(required navigation performance,RNP)的导航能力,针对直飞(track to fix,TF)航段和固定转弯半径(radius to fix,RF)航段类型,建立了飞行侧向偏差模型和飞行高度偏差模型,通过地理坐标转换,计算飞机实际飞行航迹与定义航径之间的偏差。以某新民用飞机的一次飞行为例,选取某机场进近的飞行数据进行计算,对飞行偏差进行统计,分析该飞机的适航情况及所对应的导航能力。结果表明,该飞机的基于性能导航(performance based navigation,PBN)的导航精度可满足适航标准中RNP 0.1的要求,机型执行RNP程序的质量达标。
文摘The sixth generation(6G)mobile network is envisaged to be commercially deployed around 2030,which will profoundly change people's lifestyles and accelerate the digitalization of society.To ensure that the requirements of 6G can be achieved,it is essential to establish a set of key performance indicators(KPIs).This paper comprehensively assesses the KPIs not only from the service requirements but also from the technical feasibility points of view.Specifically,theoretical derivations of KPIs have been clarified,and numerical evaluations have been conducted with reasonable technical assumptions.Evaluation results show that some KPIs defined from the service requirements can be improved through advanced technologies while some are still challenging for practical implementations,such as Tbps-level peak data rate and 0.1 ms user plane latency.In addition,it is also necessary to comply with multiple KPIs for some cases.Furthermore,based on the technical analysis,the potential enabling technologies are outlined and foreseeable implementation challenges as well as possible solutions are presented,which promotes a more reasonable design for 6G mobile network.
