航天器编队飞行及其关键技术的开发

简要论述由分布式航天器系统构成的空间编队飞行的概念 ,扼要介绍 NASA为未来航天器编队飞行项目开发的几项关键技术 ,着重阐明基于 GPS的分散式编队飞行控制和相对导航技术能充当未来多星编队飞行任务的导航系统 ,从而使未来的空间科学研究发生深刻变化     

适用于负过载启动的新型增压输送系统

介绍了一种适用于飞行器在负过载情况下启动的新型增压输送系统,该系统采用气液隔离方式,比国外可重复使用飞行器的增压输送系统结构质量轻、体积小,有利于提高飞行器的性能。分析了该系统的特点,给出了系统的主要性能参数。新型增压输送系统经过冷流试验和热试车的考核,结果均满足设计和使用要求。     

Evolution of the periodicities in 2S 0114+650

We have analysed 9 years of data from the All Sky Monitor on the Rossi X-ray Timing Explorer for 2S 0114+650 to study the evolution of its spin, binary, and super-orbital periods. The spin history of the neutron star in this system exhibits torque reversals lasting 1 year. The newly discovered super-orbital period has remained stable over the 9-year span, making 2S 0114+650 the fourth known system to exhibit stable super-orbital modulation. We compare its super-orbital period evolution with those of the other three such systems.     

高温合金K38G微晶涂层氧化动力学研究

研究了溅射微晶涂层对K38G在800℃和900℃空气中氧化动力学的影响。发现微晶化后K38G的氧化动力学与经典的抛物线规律存在负偏差。分析认为,微晶化后氧化物形核率大大提高,氧化膜中的扩散由晶格扩散变为晶界短路扩散为主,从而改变了氧化膜的生长动力学。根据Wagner高温氧化的基本理论,对微晶合金高温氧化动力学规律进行了探讨,导出微晶K38G合金氧化动力学遵循四次方规律,即x4=kPt。     

Near infrared studies of the massive X-ray binary 2S 0114+65

We present near-infrared spectroscopy of the massive X-ray binary 2S 0114+650. These observations covering the spectral range 1.08–2.35 μm span the region where Paschen and Brackett series recombination lines of hydrogen are expected to be seen, namely, Paβ , Brγ and Br 10–17 lines. The absence of any of these lines in emission supports earlier inferences that the optical component in 2S 0114+650 is unlikely to be a Be star but rather a B type supergiant. Near-IR photometry gives J = 8.78, H = 8.53 and K = 7.96; these values show marginal variations from earlier reported measurements.     

Real-time clock comparison and monitoring with multi-GNSS precise point positioning: GPS,GLONASS and Galileo

The precise point positioning (PPP) technique is widely used in time and frequency applications. Because of the real-time service (RTS) project of the International GNSS Service, we can use the PPP technique for real-time clock comparison and monitoring. As a participant in the RTS, the Centre National d’Etudes Spatiales (CNES) implements the PPPWIZARD (Precise Point Positioning with Integer and Zero-difference Ambiguity Resolution Demonstrator) project to validate carrier phase ambiguity resolution. Unlike the Integer-PPP (IPPP) of the CNES, fixing ambiguities in the post-processing mode, the PPPWIZARD operates in the real-time mode, which is also called real-time IPPP (RT-IPPP). This paper focuses on applying the RT-IPPP for real-time clock comparison and monitoring. We review the principle of real-time clock comparison and monitoring, and introduce the methodology of the RT-IPPP technique. The observations of GPS, GLONASS and Galileo were processed for the experiments. Five processing modes were provided in the experiment to analyze the benefits of ambiguity resolution and multi-GNSS. In the clock comparison experiment, the average reduction ratios of standard deviations with respect to the G PPP mode range from 9.7% to 35.0%. In the clock monitoring experiment, G PPP mode can detect clock jumps whose magnitudes are larger than 0.9 ns. The RT-IPPP technique with GRE PPP AR (G) mode allows for the detection of any clock jumps larger than 0.6 ns. For frequency monitoring, G PPP mode allows detection of frequency changes larger than 1.1 × 10⁻¹⁴. When the RT-IPPP technique is applied, monitoring with GRE PPP AR (G) mode can detect frequency changes larger than 6.1 × 10⁻¹⁵.     

通信导航融合定位技术发展综述

详细分析了蓝牙、Wi-Fi、超宽带、移动通信网络等多种无线网络通信导航融合定位技术的发展现状,并阐述了其面临的挑战,提出了多网融合方法可以提升室内无缝高精度位置服务的可靠性。利用5G移动通信网络,与北斗/GNSS卫星导航系统结合,可以实现相互增强。最后,从天地一体定位导航与授时体系和仿生通信定位导航两方面介绍了通信导航融合定位技术的未来发展趋势。     

GARMIN G1000系统维修平台设计

在分析GARMIN G1000系统结构及其内部总线规范的基础上,设计出一套集测试、诊断、维修于一体的GARMIN G1000系统维修平台,包括系统硬件设计、软件设计等。硬件设计主要包括信号模拟机、系统选择面板、信号转换模块和主控计算机等设备的设计。软件设计包括功能软件、测试软件、公用软件及数据库和帮助文档的设计与实现。实践证明该平台具有强大的故障诊断功能和良好的可扩展性,可用于G1000系统的部件测试维修工作。     

数据缺失场合下k/N(G)系统可靠性指标的经验Bayes估计

在定数截尾缺失数据样本下,研究了不可修k/N(G)系统的可靠性指标的估计问题。将极大似然估计法和Bayes方法相结合得到了部件的平均寿命、系统可靠度及平均寿命等可靠性指标的经验Bayes估计,最后利用随机模拟例子说明了本文方法的正确性和可行性。     

IPv6在3G卫星通信系统中的发展模式探讨

面对地面3G演进和NGN（Next Generation Network）的发展趋势,以空间段为基础的3G卫星通信系统与技术应该扮演怎样的重要角色、如何进一步发展,已成为一个紧迫的研究课题。文章在分析NGN对于卫星通信发展影响的基础上,介绍了目前IPv6技术的空间应用以及3G业务在卫星中的应用模式,并对IPv6技术在3G卫星通信系统中的发展模式进行了探讨。