基于数字多波束天线的多星测控系统

针对多星测控存在的问题和技术解决途径,提出采用数字波束形成技术实现单站多星测控的方案,简要说明了系统的体系结构和工作原理,指出了系统特点和技术难点。基于数字多波束天线的多星测控系统具有良好的技术基础和应用前景。     

扩频TT＆C系统设计与分析

讨论扩频TT＆C系统的概念、工作原理和工作模式,系统分析了可用于扩频TT＆C的多种系统设计方案的技术特点。     

SpaceMocap：在轨人体运动捕捉系统

SpaceMocap是一套基于多RGB-D相机的计算机视觉航天员运动捕捉系统。地面准备阶段，扫描航天员模型，并分别标定彩色相机的内参数。在轨采集阶段，3~4台相机布置在舱内角落，同步采集航天员任务视频。地面处理阶段，通过相机外参数标定和ICP方法实现点云融合，采用深度神经网络对人体关节点位置进行检测并初始化位姿参数，再用改进的ICP方法进行位姿求精，实现序列图像中关节角度跟踪。本系统搭载TG-2升空，对SZ-11航天员的任务视频进行了采集和处理，首次获取了在轨航天员的姿态(包括中性体位)、占位空间、运动参数等重要数据。结果表明，运动捕捉的模型与点云具有良好的重合度，关节点位置与关节角度具有较高的跟踪精度。SpaceMocap是我国首个在轨运动捕捉系统，它小型、轻质，具有计算机视觉特有的非接触测量、直观、高精度优势，无需在人体上粘贴任何标志，具有良好的抗遮挡能力，完全适用于微重力、狭小空间环境下的在轨应用 。     

改进的平方根UKF在再入滑翔目标跟踪中的应用

针对临近空间高超声速再入滑翔目标跟踪问题，提出了一种基于新气动力模型的改进的平方根UKF滤波算法(ISR-UKF)。首先对气动力模型进行了变换。其次，在传统平方根UKF基础上，改用球形无迹变换来计算权系数以及sigma点；改进了平方根矩阵的分解方法；同时为解决矩阵求逆易出现奇异值使滤波失效的问题，提出在协方差矩阵更新中引入多重次稳定因子。最后将该算法分别与基于原气动力的ISR-UKF，基于新气动力的平方根UKF以及基于原气动力的平方根UKF进行仿真比较。仿真表明，该算法具有良好的滤波性能，而且能避免奇异值问题的出现，具有很好的可靠性。     

Assessment of the suitability of public mobile data networks for aircraft telemetry and control purposes

This paper provides a review of the state of the art of relevant work on the use of public mobile data networks for aircraft telemetry and control proposes. Moreover, it describes the characterisation for airborne uses of the public mobile data communication systems known broadly as 3G. The motivation for this study was to explore how this mature public communication systems could be used for aviation purposes. An experimental system was fitted to a light aircraft to record communication latency, line speed, RF level, packet loss and cell tower identifier. Communications was established using internet protocols and connection was made to a local server. The aircraft was flown in both remote and populous areas at altitudes up to 8500 ft in a region located in South East Queensland, Australia. Results show that the average airborne RF levels are better than those on the ground by 21% and in the order of −77 dbm. Latencies were in the order of 500 ms (1/2 the latency of Iridium), an average download speed of 0.48 Mb/s, average uplink speed of 0.85 Mb/s, a packet of information loss of 6.5%. The maximum communication range was also observed to be 70 km from a single cell station. The paper also describes possible limitations and utility of using such communications architecture for both manned and unmanned aircraft systems.     

小型薄片零件高速铣削加工试验研究

针对小型薄片结构零件切削过程中的变形问题,以薄片"一"字电极高速铣削加工试验为例,从编程方式、切削参数选用、工序安排、走刀路线等方面展开研究。控制其变形量达到最小,以满足产品设计要求。     

Soybean cultivation for Bioregenerative Life Support Systems (BLSSs): The effect of hydroponic system and nitrogen source

Soybean [Glycine max (L.) Merr.] is one of the plant species selected within the European Space Agency (ESA) Micro-Ecological Life Support System Alternative (MELiSSA) project for hydroponic cultivation in Biological Life Support Systems (BLSSs), because of the high nutritional value of seeds. Root symbiosis of soybean with Bradirhizobium japonicum contributes to plant nutrition in soil, providing ammonium through the bacterial fixation of atmospheric nitrogen. The aim of this study was to evaluate the effects of two hydroponic systems, Nutrient Film Technique (NFT) and cultivation on rockwool, and two nitrogen sources in the nutrient solution, nitrate (as Ca(NO₃)₂ and KNO₃) and urea (CO(NH₂)₂), on root symbiosis, plant growth and seeds production of soybean. Plants of cultivar ‘OT8914’, inoculated with B. japonicum strain BUS-2, were grown in a growth chamber, under controlled environmental conditions.     

Latitudinal features of Total Electron Content over the African and European longitude sector following the St. Patrick’s day storm of 2015

GNSS TEC values have been obtained from 18 stations distributed from the magnetic equator to nearly 80°N magnetic dip in the African and west-European longitude sector corresponding to the March 17–18, 2015 geomagnetic storm. Significantly depleted ionosphere have been observed at stations north of 50°N geographic on March 18, 2015 following the above storm over a longitude swath 11.9°–21°E covering the Eastern Africa and Western European longitude sector. High ROTI values were noted on March 17^th at locations around 80°N magnetic dip. Two prominent peaks in PCN were noted around 09:00 UT and 14:00 UT on March 17, 2015 and around 15:00 UT on March 18, 2015. Daytime thermospheric (O/N₂) ratio was markedly less on March 18th at latitudes above 60°N geographic which is suggested to be the major driver behind depleted high latitude ionosphere during the recovery phase of the storm on March 18, 2015.     

基于激光激励的火工冲击响应及其特性研究

针对传统火工冲击激励方法在频率范围方面的局限性，研究新兴的激光激励方式、激励特性及其参数的影响，探究模拟火工冲击试验的可行性。首先参考经典的冲击试验方法，制定了激光激励试验的试验方案，设计了试验装置并进行了冲击试验；然后针对火工冲击和激光激励的试验结果，在时域、频域进行了时频分析和响应谱分析与对比；最后依据该试验方法，讨论了激光脉冲频率和激光脉冲能量对冲击响应的影响。研究提出的激光激励方法对火工冲击机理研究与地面模拟试验设计具有一定的参考价值。     

波音737NG飞机液压油渗漏专项治理

对液压渗漏故障数据进行分析,根据故障发生频率,将液压系统渗漏问题按照系统或部件进行分类,与波音工程师一起进行现场研究,通过专题研讨会的形式深入分析,获得了相关维护建议和液压系统施工的培训材料,并总结编写液压油渗漏部件区域检查工作单,对解决液压渗漏故障有很大的帮助。