Pose measurement of large non-cooperative satellite based on collaborative cameras

In recent years some communications satellites lost their ability due to the failure of mechanisms to deploy, which resulted in large cost. A space robotic system is expected to perform the on-orbit repairing mission. This is a tremendous challenge since the targets are generally non-cooperative, i.e. no facilities used for relative state measurement are mounted on the targets. Moreover these targets are very large. Limited by the FOV (field of view), a monocular camera cannot supply enough information of the targets in close range. In this paper, a method based on two collaborative cameras is proposed to determine the pose (position and orientation) of a large non-cooperative target. Firstly, we designed a sensing system used for the non-cooperative measurement, according to the investigation of the characteristics of communications satellites. A rectangular feature, which is common in the configuration of a satellite, is chosen as the recognized object. Secondly, we proposed that two cameras share the recognition task in a collaborative behavior, i.e. each provides partial image of the rectangle, and the full feature is then obtained by fusing their information. Lastly, the corresponding algorithm of image processing and pose measurement is addressed. Simulation results of typical cases verify the proposed approach.     

飞机整体壁板广义槽分层识别方法及其实现算法(英文)

To automatically obtain a machining area in numerical control （NC） programming, a data model of generalized pocket is established by analyzing aircraft integral panel characteristics, and a feature recognition approach is proposed. First, by reference to the practical slice-machining process of an aircraft integral panel, both the part and the blank are sliced in the Z-axis direction; hence a feature profile is created according to the slicing planes and the contours are formed by the intersection of the slicing planes with the part and its blank. Second, the auxiliary features of the generalized pocket are also determined based on the face type and the position, to correct the profile of the pocket. Finally, the generalized pocket feature relationship tree is constructed by matching the vertical relationships among the features. Machining feature information produced by using this method can be directly used to calculate the cutter path. The validity and practicability of the method is verified by NC programming for aircraft panels.     

认真落实“十一五”规划纲要 全面加强应急管理体系建设

2002年底至2003上半年爆发的非典疫情对我国社会造成了十分严重的危害。在严峻的形势下，我国政府充分发挥社会管理与公共服务职能，在短时间内集中大批的人力、物力，带领全国人民团结一心，众志成城，最终赢得了抗击非典的重大胜利。但是，面对成绩党和国家的领导人依然保持了清醒的头脑，敏锐地认识到我国在应对突发公共事件方面存在的各种问题和种种不足。非典过后，党中央、国务院一方面迅速进行社会秩序的恢复工作，另一方立即组织有关部门认真总结经验教训，并将提高全社会应对突发公共事件能力安排到了工作日程之中，明确提出了“要建立健全社会预警体系，提高政府应对突发事件和风险的能力，形成统一指挥、功能齐全、反应灵敏、运转高效的应急机制，提高保障公共安全和处置突发公共事件能力”的工作目标。     

UDMH/NTO双组元凝胶推进剂的制备及性能研究

对UDMH/NTO(偏二甲肼/四氧化二氮)双组元推进剂凝胶剂进行筛选的基础上,分别制备了UDMH与NTO凝胶推进剂,利用Brookfield流变仪研究了其流变性能;在进行了初步发动机试验后发现,氧化剂凝胶的无机凝胶剂颗粒会堵塞管路而使试验不能正常进行。通过对氧化剂凝胶的改进,重新建立了氧化剂凝胶体系并研究了其流变性能。发动机试验表明:新的UDMH/NTO双组元凝胶体系能够满足发动机设计对凝胶推进剂的要求。     

飞行加速度对固体发动机前封头内绝热层烧蚀的影响

固体火箭发动机前封头内绝热层在飞行加速过程中的烧蚀率是地面静止试验的１．０￣２．３倍。概述了国外在飞行加速对烧蚀影响这方面的研究结果，对国内３台固体火箭发动机内绝热层烧蚀率进行了估计和分析，认为，由于绝热层设计安排裕度比较大，因而这三种发动机飞行条件下的烧蚀仍在安排范围之内。     

一种基于高斯-塞得尔迭代的信道均衡算法

由于运算量大,以及对快衰落信道的无能为力,自适应均衡器的使用受到了很大的限制。将高斯-塞得尔迭代用于信道均衡,提出了一种基于信道估值的信道均衡算法,主要分析了小数抽头决策反馈均衡器的性能,并与整数抽头均衡器作了比较。     

Global geomagnetic response to a sharp compression of the magnetosphere and IMF variations on October 29, 2003

We study the response of the ionosphere and magnetosphere to a sudden commencement (SC) on October 29, 2003, at 06:11 UT. It is shown that the geomagnetic response had the form of two successive stages. In the first 5 min after the SC, a strong intensification of a two-vortex current system of the DP2 type was observed in latitudes 67°-65°, with variations of H -4000 nT (+700 nT). At the same time, energetic electrons were injected without dispersion to geosynchronous orbits simultaneously in the sectors 16, 04, and 07 MLT. In the subsequent 5–15 min, a new intensification of the western electrojet took place in all time sectors at latitudes 70°. Around midnight, this electrojet was extended in the poleward direction up to the polar cap latitudes ( 75°-83°). It had an unusually high velocity of extension (up to 5.0 km/s) and was accompanied by typical dispersionless substorm injections, but only at meridians 04 and 07 MLT. From comparing the development of electrojets with the data of satellite observations in the solar wind and magnetosphere, we suggest that 3–5 min after the SC onset a dipolization of the magnetic field at the geosynchronous orbit occurred. It was connected with the decay of the current flowing across the magnetotail. The subsequent extension of the region of current decay into the tail up to 150 R_E proceeded with a velocity of 1000 km/s, which exceeds the known velocities of such an extension by a factor of 5.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 622–631.Original Russian Text Copyright © 2004 by Solovyev, Moiseyev, Mullayarov, Du, Engebretson, Newitt.     

喷气战斗机发动机安装车设计和发展研究

发动机安装车是用于发动机拆装作业的重要保障设备,美国的先进安装车设计具有很好的研究和借鉴价值.本文全面介绍和分析了美国各型现代战斗机发动机安装车的设计,包括布局和结构形式、细节设计、标准化和通用化设计等,以Air Log 4000安装车为标杆,与其他安装车进行比较,揭示了安装车设计解决方案的差异性和多样性,以及技术发展演进特点和发展方向,并提出了借鉴国外先进设计,研制有自身特色的先进安装车产品的建议.     

FY-2卫星的空间环境数据接收及警报系统

介绍了FY—2卫星探测数据的流通过程及接收处理．首先在FY-2卫星及探测器系统中，环境探测数据被收集、调制并发射，再由地基数据接收及解调系统将数据信号放大、解调还原并发送，最后由数据处理及警报系统将数据接收处理、保存显示，并对太阳质子事件、x耀斑进行自动电话报警．该系统是保障航天器安全和提高抗辐照水平的重要手段．     

硝胺复合推进剂抗撕裂性能的研究

以ＡＰ／ＲＤＸ／ＨＴＰＢ复合固体推进剂为对象，研究了撕裂速率，添加剂类型，贮存老化等因素对推进剂撕裂性能的影响，实验结果表明，撕裂速率加大使推进剂断裂能升高；不同的添加剂对推进剂的断裂能有不同的影响，键合剂使断裂能升高，推进剂老化一段时间后断裂能降低。