组合系统接收机自备完善性监测和导航性能研究

本文根据ＡＲＰ准则研究了不同数量卫星发生硬故障、飞机非精密进场或终端航行时，ＧＰＳ／气压高度表组合系统和ＧＰＳ／ＧＬＯＮＡＳＳ／气压高度表组合系统接收机自备完善性监测（ＲＡＩＭ）和导航解的可用性。结果表明：ＧＰＳ／气压高度表组合时，ＲＡＩＭ性能不能满足ＴＳＯ－Ｃ－１２９的规定；而ＧＰＳ／ＧＬＯＮＡＳＳ／气压高度表组合系统可作为辅助导航系统用于飞机非精密进场或终端航行。这两种组合系统都有较好的导航性能     

GPS组合系统接收机自备完善性监测和导航性能研究

本文根据ＡＲＰ准则研究了不同数量卫星发生硬故障，飞机非精密进场或终端航行时，ＧＰＳ／气压高度表组合系统和ＧＰＳ／ＧＬＯＮＡＳＳ／气压高度表组合系统接民睡机自备完善性监测（ＲＡＩＭ）和导航解的可用性，结果表明：ＧＰＳ／气压高度时组合时，ＲＡＩＭ性能不能满足ＴＳＯＣ－１２９的规定；而ＧＰＳ／ＧＬＯＮＡＳＳ／气压高主工表组合系统可作为辅助导航系统用于飞机非精密进场或终端航行，这两种组合系统都有较好的导航     

GLONASS的评述和发展

导航星全球定位系统不是仅供城市中应用,尽管目前所发射的卫星数目还不够,但在民用独立定位精度方面,俄罗斯的ＧＬＯＮＡＳＳ明显要优于目前加有ＳＡ的ＧＰＳ定位精度,在本文中,我们将简要评述ＧＬＯＮＡＳＳ的技术特性,并同ＧＰＳ进行比较和对照,我们还将评估ＧＬＯＮＡＳ目前的发展和性能,并且简要描述ＧＬＯＮＡＳＳ和综合ＧＰＳ／ＧＬＯＮＡＳＳ兼容接收机。     

全球卫星导航系统的近期进展

２０世纪末,卫星导航发展势态出现了ＧＬＯＮＡＳＳ星座维持困难,ＧＰＳ推行现代化计划和欧洲Ｇａｌｉｌｅｏ计划出台三大新闻。有望于２０１０年左右Ｇａｌｉｌｅｏ星座和ＧＰＳ星形成互补和卫为余度。最近,美国国会削减ＧＰＳ预算,在ＧＰＳ民用进展上投下阴影,ＧＰＳ单一导航手段暂难实行,有利于欧洲争取时间,积极筹措Ｇａｌｉｌｅｏ系统。     

NUMERICAL SIMULATION OF THE FLOW PAST WING-BODY USING EULER EQUATIONS

ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＴＨＥＦＬＯＷＰＡＳＴＷＩＮＧ－ＢＯＤＹＵＳＩＮＧＥＵＬＥＲＥＱＵＡＴＩＯＮＳＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＴＨＥＦＬＯＷＰＡＳＴＷＩＮＧ－ＢＯＤＹＵＳＩＮＧＥＵＬＥＲＥＱＵＡＴＩＯＮＳ￥Ｃｈｅｎ...     

ANALYTICAL－GENERALIZED VARIATIONAL METHOD ABOUT SOLUTION OF SIF AND CONSERVATIVE INTEGRAL FOR DELAMINATlONS OF LAMINATE BEAM

ＡＮＡＬＹＴＩＣＡＬ－ＧＥＮＥＲＡＬＩＺＥＤＶＡＲＩＡＴＩＯＮＡＬＭＥＴＨＯＤＡＢＯＵＴＳＯＬＵＴＩＯＮＯＦＳＩＦＡＮＤＣＯＮＳＥＲＶＡＴＩＶＥＩＮＴＥＧＲＡＬＦＯＲＤＥＬＡＭＩＮＡＴｌＯＮＳＯＦＬＡＭＩＮＡＴＥＢＥＡＭＡＮＡＬＹＴＩＣＡＬ－ＧＥＮＥ...     

A TRACTION CALCULATING FORMULA BASED ON NON-NEWTONIAN RHEOLOGICAL MODEL

ＡＴＲＡＣＴＩＯＮＣＡＬＣＵＬＡＴＩＮＧＦＯＲＭＵＬＡＢＡＳＥＤＯＮＮＯＮ－ＮＥＷＴＯＮＩＡＮＲＨＥＯＬＯＧＩＣＡＬＭＯＤＥＬＡＴＲＡＣＴＩＯＮＣＡＬＣＵＬＡＴＩＮＧＦＯＲＭＵＬＡＢＡＳＥＤＯＮＮＯＮ－ＮＥＷＴＯＮＩＡＮＲＨＥＯＬＯＧＩＣＡＬＭＯＤＥ...     

高阶各向异性k－ε模型及在直通道湍流流场中的数值研究

ＡＨＩＧＨ－ＯＲＤＥＲＡＮＩＳＯＴＲＯＰＩＣＫ－εＭＯＤＥＬＡＮＤＩＴＳＮＵＭＥＲＩＣＡＬＩＮＶＥＳＴＩＧＡＴＩＯＮＩＮＴＷＯＤＩＭＥＮＳＩＯＮＡＬＴＵＲＢＵＬＥＮＴＦＬＯＷＦＩＥＬＤＳＬｉｕＺｈｅｎｇｘｉａｎ，ＳｏｎｇＢａｏｊｕｎ，ＧｕＣｈｕａｎｇ...     

半波GLM方法封闭的湍流方程对转捩过程的数值模拟

ＴＲＡＮＳＩＴＩＯＮＳＩＭＵＬＡＴＩＯＮＵＳＩＮＧＧＬＭ－ＥＭＢＡＳＥＤＣＬＯＳＥＤＥＱＵＡＴＩＯＮＳＯＦＴＵＲＢＵＬＥＮＣＥＧａｏＧｅ（４ｔｈＤｅｐｔ．ＢｅｉｊｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆＡｅｒｏｎａｕｔｉｃｓａｎｄＡｓｔｒｏｎａｕｔｉｃｓ，Ｂｅ...     

STUDY ON THERMAL EXPANSION COEFFICIENT AND DESIGN FOR ZERO－EXPANSION OF SlNGLE AND HYBRID MULTI－DIRECTIONA

ＳＴＵＤＹＯＮＴＨＥＲＭＡＬＥＸＰＡＮＳＩＯＮＣＯＥＦＦＩＣＩＥＮＴＡＮＤＤＥＳＩＧＮＦＯＲＺＥＲＯ－ＥＸＰＡＮＳＩＯＮＯＦＳｌＮＧＬＥＡＮＤＨＹＢＲＩＤＭＵＬＴＩ－ＤＩＲＥＣＴＩＯＮＡＬＣＯＭＰＯＳＩＴＥＳＺｈｏｎｇＷｅｔｈｏｎｇ；ＺｈａｎｇＺｕｏ...     

GPS／GLONASS共用PDOP研究

对全球卫星定位系统的DOP因子进行了分析。对GPS/GLONASS共用系统的可用性和PDOP因子进行了理论分析和软件仿真,对星座的定位特性进行了评估。分析结果表明,GPS/GLONASS共用系统相对于单一的GPS系统在可用性和PDOP因子方面都有很大的改善,从而可以进一步改善定位精度,这就为GPS/GLONASS组合导航的进一步研究和应用奠定了基础。     

Federal Radionavigation Plan-pie in the sky for civil aviation?

The Federal Radionavigation Plan states that all present navigation and landing guidance facilities will be retired starting in 2005, and full dependence for these functions will be placed on augmented GPS. Once this is implemented, civil aviation will be totally vulnerable to terrorist jamming of the GPS signals over wide earth areas with widespread disruption of air traffic and potential disasters. It has become apparent that the use of GPS/GNSS is complex and expensive for the required civil aviation functions. It is clear that a different system form is needed for civil aviation, a redundant satellite/ground based system that will prevent it from being a jamming target while providing ATC surveillance, area navigation, collision warning/avoidance, high-speed data link and Category I landing guidance globally, plus precision Category III guidance in the terminal areas as needed. Such a system will be described     

基于残差x^2故障检测的IRS／GPS紧组合算法研究

对于民用航空来说,除了精度指标外,可靠性指标也十分重。组合导航技术可以极大的提高导航系统的精度,对组合导航系统进行实时的故障检测可以有效提高导航系统的可靠性。本文对基于残差x^2故障检测的IRS／GPS紧组合算法进行研究,并进行相应的仿真分析。仿真结果表明设计的组合导航和故障检测方案可以有效隔离GPS故障量测,在GPS存在故障时仍能保持较高的定位精度,提高组合导航系统的可靠性,具有重的工程应用价值。     

A GPS/GLONASS/INS test program

Under contract of different German Ministries a test program investigating the combinations of GPS, GLONASS, and Inertial Navigation has been carried out since 1991. Besides other goals, the aim of the project is to investigate the capabilities of GLONASS in comparison to GPS, to realize a combined GLONASS/INS solution and to perform joint processing of GPS and GLONASS raw data. The paper describes the test procedures and presents some of the results. This includes the comparison of DGPS with stand-alone GLONASS and GLONASS/INS under different dynamic situations, e.g., driving tests, flight tests, and also the presentation of results of combined GPS/GLONASS data processing, which was successfully achieved in March '93 for the first time. The results show the potential of the non-SA-degraded GLONASS and the advantage of using both, GPS and GLONASS for combined solutions     

卫星导航系统发展动态

卫星导航系统是20世纪60年代中期发展起来的一种新型导航系统，90年代，卫星导航时入全运行和盛行时期，除了用于陆上，海上和空中的航行引导外，几乎扩展到军事和经济的各个方面，目前，除了已经运行的美国的GPS（全球定位系统）和俄罗斯的GLONASS（全球导航卫星系统）外，欧盟也正在积极开发伽利略系统。本文分别介绍GPS、GLONASS和伽利略系统的发展状况。     

The Soviet Union's GLONASS Navigation Satellites

GLONASS (Global Orbiting Navigation Satellite System) is the most recent satellite navigation system developed by the Soviet Union and currently in the pre-operational stage. Obvious parallels exist between GLONASS and the NAVSTAR Global Positioning System (GPS) developed in the United States and also, at present, in a pre-operational phase. In the progress towards operational status, the launch capability for NAVSTAR satellites has been seriously affected by the recent failure of the Space Shuttle Challenger, clearly increasing the prospects of GLONASS reaching operational status first. It is therefore the main purpose of this paper to discuss certain aspects of the GLONASS satellite navigation system, in particular its orbital features and radio-frequency signal characteristics. Comparisons with NAVSTAR are inevitable and for this reason, the paper begins with a brief resume of relevant features of the NAVSTAR GPS system for later reference. The main section of the paper then deals with orbital behaviour, radio frequency signal structure and channelisation using NAVSTAR as a reference point for discussion.     

GPS/SINS超紧组合导航的性能分析

GPS接收机在高动态环境下很容易失锁,特别是载体的高动态造成的应力对接收机载波跟踪环影响很大。为了解决高动态环境下的组合导航,分析了GPS接收机载波跟踪环的测量误差和跟踪门限,采用惯导速度辅助GPS接收机跟踪环路的超紧组合结构。超紧组合需要涉及到GPS接收机跟踪环内部编排及高动态环境下的实验数据,难度较大。针对超紧组合仿真专门开发了GPS实时软件接收机、高动态GPS中频信号仿真器和惯导模拟器并构建了一个完整的GPS/SINS超紧组合仿真系统。仿真结果表明,该超紧组合导航系统可以跟踪50g的加速度和10倍音速。     

EGNOS: project status overview

The European Geostationary Navigation Overlay System (EGNOS) is being developed in Europe to provide GPS and GLONASS satellite-based augmentation services to aviation, maritime and land users. EGNOS is a major element of the European Satellite Navigation Programme which is jointly being implemented by the European Union, the European Space Agency (ESA) and EUROCONTROL.     

GPS和GLONASS广播星历参数分析及算法

GPS和GLONASS作为当今世界上在轨运行的两大卫星导航系统,其广播星历参数的设计和算法各具特点。本文探讨了GPS和GLONASS广播星历参数设计的物理背景,对它们各自的特征进行了分析比较,最后文章给出了GPS广播星历参数的一种拟合算法。     

Subspace array processing for the suppression of FM jamming in GPS receivers

The mitigation of FM interference in GPS receivers is considered. In difference to commonly assumed wideband and narrowband interferers, the FM interferers are wideband, but instantaneously narrowband, and as such, have clear time-frequency (TF) signatures that are distinct from the GPS coarse acquisition (C/A) spread spectrum code. In the proposed technique, the estimate of the FM interference instantaneous frequency (IF) and the interference spatial signature are used to construct the spatiotemporal interference subspace. The IF estimates can be provided using existing effective linear or bilinear TF methods. The undesired signal arrival is suppressed by projecting the input data on the interference orthogonal subspace. With a multisensor receiver, the distinctions in both the spatial and TF signatures of signal arrivals allow effective interference suppressions. The deterministic nature of the signal model is considered and the known underlying structure of the GPS C/A code is utilized. We derive the receiver signal-to-interference-plus-noise ratio (SINR) under exact and perturbed IF values. The effect of IF estimation errors on both pseudorange measurements and navigation data recovery is analyzed. Simulation results comparing the receiver performances under IF errors in single and multiantenna GPS receivers are provided.