A new approach to the telescope operation method for satellite tracking using a time synchronization technique

For the development of a telescope that is capable of precisely tracking satellites and high-speed operation such as satellite laser ranging, a special method of telescope operation is required. This study aims to propose a new telescope operation method and system configuration for the independent development of a mount and an operation system which includes the host computer. Considering that the tracking of a satellite is performed in real time, communication and synchronization between the two independent subsystems are important. Therefore, this study applied the concept of time synchronization, which is used in various fields of industry, to the communication between the command computer and the mount. In this case, communication delays do not need to be considered in general, and it is possible to cope with data loss. Above all, when the mount is replaced in the future, only the general communication interface needs to be modified, and thus, it is not limited by replacement in terms of the overall system management. The performance of the telescope operation method developed in this study was verified by applying the method to the first mobile SLR system in Korea. This study is significant in that it proposed a new operation method and system configuration, to which the concept of time synchronization was applied, for the observation system that requires an optical telescope.     

基于S1000D标准的飞机技术出版物结构化方法研究

飞机技术出版物结构化可实现技术出版物内容基于公共数据源的编写、管理和发布,能有效提高技术出版物的编制效率和质量。基于 S1000D 标准提出 MA700 飞机技术出版物结构化设计思路,给出结构化方法的总体流程,探讨每一步结构化方法的实现要素,重点进行结构化标准选择、技术出版物业务规则制定说明,并给出相应实例和 DMRL 制定原则。结果表明：本文提出的结构化流程和方法能够用于指导 MA700 飞机技术出版物结构化,提高 MA700 飞机技术出版物的易用性、可读性,有利于 MA700 飞机技术出版物的规范化、标准化、国际化,为基于 S1000D 的 MA700 飞机交互式电子技术出版物系统的构建和发布提供业务支持。     

专用IP网端到端QoS保证方案研究

用于航天测控通信的专用IP网实现了话音、图像、数据等多种业务的综合传输。随着流量的增加,网络发生拥塞的可能性也逐渐增大。如何避免拥塞,确保重要数据高实时、高可靠的传输已成为了必须深入研究的课题。本文介绍了IntServ和DiffServ模型,分析了专用IP网的QoS要求,提出了端到端QoS保证方案。最后搭建了实物环境,对方案进行了实验验证,结果表明,使用QoS保证技术后,重要业务数据的实时性和可靠性得到了较好的保证。     

我国农村社会保障体系的构建与完善

完善农村社会保障体系是“十七大”的目标之一,也是我国社会保障体系的重要组成部分,对于构建和谐社会意义重大。通过对农村社会保障的演变过程回顾,分析了现行农村社会保障存在的问题及其成因,阐述改革应遵循的原则,提出完善农村社会保障体系的构想。     

基于LabVIEW的陀螺平台测试系统设计与实现

陀螺平台的测量与控制是现代工业生产和试验过程中经常遇到的问题。针对传统陀螺平台测试系统的一些不足,研制了一种基于LabVIEW的陀螺平台测试系统。该系统以PXI总线型计算机为控制核心,综合运用了数据采集和转换技术,多种信号综合变换处理,实现了测试系统智能化,测试项目和指标满足陀螺平台的测试要求。     

Damage localization effects of the regeneratively-cooled thrust chamber wall in LOX/methane rocket engines

To investigate the damage localization effects of the thrust chamber wall caused by combustions in LOX/methane rocket engines, a fluid-structural coupling computational methodology with a multi-channel model is developed to obtain 3-demensioanl thermal and structural responses. Heat and mechanical loads are calculated by a validated finite volume fluid-thermal coupling numerical method considering non-premixed combustion processes of propellants. The methodology is subsequently performed on an LOX/methane thrust chamber under cyclic operation. Results show that the heat loads of the thrust chamber wall are apparently non-uniform in the circumferential direction. There are noticeable disparities between different cooling channels in terms of temperature and strain distributions at the end of the hot run phase, which in turn leads to different temperature ranges, strain ranges, and residual strains during one cycle. With the work cycle proceeding, the circumferential localization effect of the residual strain would be significantly enhanced. A post-processing damage analysis reveals that the low-cycle fatigue damage accumulated in each cycle is almost unchanged, while the quasi static damage accumulated in a considered cycle declines until stabilized after several cycles. The maximum discrepancy of the predicted lives between different cooling channels is about 30%.     

汽车动态测试-DVT

介绍了DVT测试这一先进的汽车动态测试和诊断手段的发展，并结合生产实际介绍了DVT测试的全过程，同时列举了一些典型的故障分析诊断实例，阐释了DVT测试的优点，它能够方便、快速地诊断出汽车的故障，保证汽车的装配质量，提高汽车出厂安全系数。     

基于.NET的有线电视网上收费系统设计方法研究

随着有线电视用户的日益增多,有线电视台的业务量也日益膨胀,建设基于网络的客户服务模式已经成为必然趋势。该文对有线电视网上收费系统实现的关键技术进行了深入的分析,提出了一套基于.NET的分布式多层体系结构解决方案,该方案充分考虑了系统的健壮性、灵活性、可伸缩性,从而实现了系统在物理平台和逻辑平台上的跨越与提高。     

岁差章动模型更新等因素对坐标转换的影响

GCRS(Geocentric Celestial Reference System,地心天球参考系)与ITRS(International Terrestrial Reference System,国际地球参考系)之间的坐标转换方法与岁差章动模型密切相关,IERS(International Earth Rotation and reference systems Service,国际地球自转与参考系服务)规范先后推荐了3组不同的岁差章动模型。论文分析了基于春分点的坐标转换过程,在比较3组岁差章动模型间差异的基础上,以太阳系10个天体为例,计算了岁差章动模型更新、极移、世界时与地球时差值等因素对坐标转换影响的具体数值。结果表明,IAU 2006岁差-IAU 2000AR06章动与IAU 2000岁差-IAU 2000A章动间的差异,对坐标转换的影响在0.5mas以内;而IAU1976岁差-IERS 1996章动与前2组岁差章动间的差异,对坐标转换影响的最大值达到37mas;极移对坐标转换影响的最大值达到0.6″,远高于岁差章动模型更新所带来的影响;当忽略世界时与地球时的差异时,结果完全错误。通过此分析,明确了极移、世界时与地球时的差异对坐标转换影响的具体数值,可为工程计算中岁差章动模型的选取提供参考依据。     

海事BGAN系统数据链路测试及性能分析

概述了海事第4代卫星及BGAN系统的基本情况,针对某特殊用户对BGAN系统提出的要求,在数据Standard IP型和信道Streaming IP型2种通信业务模式下,对通信网络链路的时延、抖动、丢帧等性能进行测试实验,分析测试结果,证实了BGAN系统在远洋船舶中使用的可行性。