Lateral Flight Technical Error Estimation Model for Performance Based Navigation

Flight technical error (FTE) combined with navigation system error (NSE) is the main part of total system error (TSE) in performance based navigation (PBN).The implementation of PBN requires pre-flight prediction and en-route short-term dynamical prediction of the TSE.Once the sum of predicted lateral FTE and NSE is greater than the specified PBN value,the PBN cannot operate.Thus,accurate modeling and thorough analysis of lateral FTE are indispensible.Multiple-input multiple-output (MIMO) lateral track control system of a transport aircraft is designed using linear quadratic Gaussian and loop transfer recovery (LQG/LTR) method,and the lateral FTE of a turbulence disturbed approach operation is analyzed.The error estimation mapping function of latera FTE and its bound estimation algorithm are proposed based on singular value theory.According to the forming mechanism of lateral FTE,the algorithm considers environmental turbulence fluctuation disturbance,aircraft dynamics and control system parameters.Real-data-based Monte-Carlo simulation validates the theoretical analysis of FTE.It also shows that FTE is mainly caused by turbulence fluctuation disturbance when automatic flight control system (AFCS) is engaged and would increase with escalating environmental turbulence intensity.     

基于多核融合的目标大面积遮挡处理方法

提出了一种基于多核融合的目标遮挡处理方法,用于提高大面积遮挡情况下视觉目标跟踪算法的鲁棒性和准确性.与现有基于单个对称核加权直方图的mean shift跟踪算法不同,该方法以目标区域内的多个非中心位置为核函数中心,构建多个非对称核加权直方图.由于这些直方图对目标的不同区域赋予了不同的权重,使得在遮挡发生时总存在一些直方图受影响较小.依据各个直方图分别进行mean shift迭代获得一组目标位置估计后,利用D-S证据理论融合判定最终的目标位置.实验结果表明,该方法在目标被大面积遮挡时仍能够获得准确的跟踪.     

总经理致辞

亲爱的旅客:您好!非常高兴与您相逢在中国国际航空公司的班机上!感谢您选择乘坐国航的航班,对于您给予国航安全服务品质的信赖,我们感到不胜荣幸。作为我国唯一载国旗的航空公司的一名高级管理者,我每时每刻都感到自己使命光荣,更感到责任重大。目前,国航已     

SAP——追求完美工厂解决方案

完美工厂是一个理想状态的终极目标,可以帮助企业直接将生产战略和企业目标保持一致。对完美工厂的追求使得工厂员工、运营团队和IT人员可以共同设计工厂战略并确定其优先顺序,以及实施影响产品计划、智能、整合和执行等核心元素的工厂战略。     

China''s Space Activities

Currently, space activities are very active around the world. Space technologies continuously expand to various areas of human activities, and space technology and applications are becoming an indispensable part of modern information society,while the development of space science brings a brand-new view to the development of science and technology. The development of space law is not only an important approach to improving people' s quality of lives, expanding the living space of human being, and exploiting new resources, but also an important symbol of the comprehensive strength and civilization of a nation.     

Satellite Constellation Design with Adaptively Continuous Ant System Algorithm

The ant system algorithm （ASA） has proved to be a novel meta-heuristic algorithm to solve many multivariable problems. In this paper, the earth coverage of satellite constellation is analyzed and a n ＋ 1^ -fold coverage rate is put forward to evaluate the coverage performance of a satellite constellation. An optimization model of constellation parameters is established on the basis of the coverage performance. As a newly developed method, ASA can be applied to optimize the constellation parameters. In order to improve the ASA, a rule for adaptive number of ants is proposed, by which the search range is obviously enlarged and the convergence speed increased. Simulation results have shown that the ASA is more quick and efficient than other methodV211.71s.     

SMART STRUCTURES USING PIEZOELEMENTS FOR ACTIVE VIBRATION AND NOISE SUPPRESSION IN AVIATION AND AEROSPACE

具有减振降噪功能的压电智能结构是智能材料与结构的一个重要分支。在航空航天领域存在一些典型结构，如飞机机舱、空间站、卫星太阳能帆板和通讯天线以及直升机旋翼等，其振动与辐射噪声造成很多不利影响。为了研究这些结构的振动与噪声控制方法，制作了几个实验模型如大型薄壁复合材料圆桶、柔性梁、钢架及旋翼系统模型，通过压电传感器、驱动器布置数量和位置的优化，采用不同的控制算法，在基于个人计算机的测控平台上进行了振动控制实验，取得了明显的减振降噪效果。     

CAI课件的创作策略与使用体会

本文结合自己开发和使用《微机应用基础》多媒体教学课件实践过程，简单阐述了几点CAI课件创作的一般策略和使用体会。     

我校大学生心理健康状况不容乐观

本文用SCL－90症状自评量表方法，对我校三个年级的部分班级进行了测查。分析表明：我院大学生的心理健康状况不容乐观。本文还对学生管理现状提出了进一步改进建议。     

正电子素络合形成研究(Ⅱ)

本文讨论了不同测量条件对正电子素络合反应速度常数测定值的影响。实验结果表明,在稀溶液的条件下,使用我们特殊设计的盛装溶液的匣式容器能大大提高放射源的使用率并能完全避免放射性废水。