共查询到18条相似文献,搜索用时 109 毫秒
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SISA完备性监测与WUL可靠性算法 总被引:1,自引:0,他引:1
详述了Galileo完备性概念,分析了空间信号有效参数完备性监测系统和监测机理,给出Galileo系统中描述SISA预报形式和算法模型.基于空间信号完备性参数的算法,优化计算最坏用户位置方法,建立了算法模型,得出相应结论.算法和结论初步验证适用于全球,为进一步研究Galileo系统完备性算法和估计用户保护水平奠定基础. 相似文献
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多系统多频率的EGNOS系统完备性模拟分析 总被引:2,自引:0,他引:2
推导了EGNOS系统不同频率情况下的完备性算法。针对GPS和GPS/Galileo组合导航的情况,模拟计算了EGNOS增强系统能为多频用户提供的完备性能。分析结果表明,EGNOS能够使GPS/Galileo系统的双频用户满足Cat-Ⅰ飞行阶段的完备性要求。 相似文献
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卫星自主完备性监测方法(SAIM)是将完备性监测功能直接设置于导航卫星之中,每个卫星的SAIM子系统只用于监测该卫星本身的测距信号(码、相位/信号、导航信息等),而不像广域增强系统(WAAS)、空基增强系统(SBAS)、地基增强系统(GBAS,LAAS)那样必须同步处理12颗或更多颗卫星的信息。因此SAIM可以在1s之内完成对该卫星信号的完备性监测,并向用户发出完备性监测信息。它可以满足几乎所有用户对完备性的要求,甚至不用任何增强也能满足民航部门CAT Ⅰ级精密进近的技术指标。对于完备性监测要求十分高的应用,例如民航CAT 相似文献
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欧洲的全球卫星导航系统的开发分为两个阶段,第一阶段的主要任务是发展EGNOS(European Geo-stationary Navigation OverlaySystem)系统,第二阶段是全球卫星导航系统Galileo系统。主要介绍EGNOS系统。EGNOS是一种星基的广域增强系统,利用地球静止卫星播发测距增强信号、完备性信号、卫星轨道参数、钟差改正信号和电离层改正信号,从而极大地改善了卫星定位的精度、完备性和可用性。EGNOS测试系统简称ESTB(EGNOS SystemTest Bed),ESTB在最大程度上减少了EGNOS系统的复杂度,重点考虑了它的可用性、健壮性和其他一些辅助设施。 相似文献
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Galileo系统是欧盟提出并正在研制建设的全球卫星导航定位系统,本文从用户使用角度出发,简要论述了Galileo系统频率计划和信号体制设计情况,详细分析了不同频点、不同信号体制下Galileo系统接收机测距性能。 相似文献
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卫星导航系统基本完好性监测对象是基本导航电文,其算法模型有两种:一是用户伪距精度(URA)和实时用户距离精度(RURA);二是空间信号精度(SISA)和空间信号监测精度/完好性标示(SISMA/IF).通过对卫星导航系统基本完好性监测技术进行分析定义,研究了系统基本完好性的两种主流算法.分别在正常情况下、卫星钟差和轨道... 相似文献
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Galieo系统频率和信号设计现状 总被引:1,自引:0,他引:1
介绍了Galileo系统频率和信号设计方案。对Galileo系统选用的信号频段、各频段的中心频率、码率等主要参数、Galileo系统服务与信号的对应关系进行了研究。并对Galileo系统和GPS系统的兼容性和协同工作性进行了比较分析。 相似文献
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卫星导航完备性监测的最新进展 总被引:2,自引:1,他引:1
自从美国于2000年取消GPS SA政策并开始实施GPS现代化,以及欧洲伽利略导航系统正式开始启动以来,在完备性监测技术方面出现了许多新的发展和动向,本文将对其作简要的介绍。GPS和伽利略的完备性监测新技术主要包括:卫星自主完备性监测(SAIM)、星载和星间完备性监测、伽利略完备性能力评估(GIPA)的概念、用户自主完备性监测(UAIM)等。 相似文献
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利用GALILEO全球监测网络和中国地壳运动监测网络分别对GALILEO系统完备性指标SISMA进行仿真计算。结果表明,全球完备性监测SISMA结果不稳定,随地理位置的变化较大,不能满足局部地区的生命安全服务要求;利用适当布设的局域监测网络进行的SISMA局域监测数值稳定,变化较小,结果明显优于全球SISMA监测结果,可以满足生命安全服务要求,可信度达到100%。在我国进行局域SISMA监测,是对全球完备性监测进行的有效和必要补充,提高系统的可用性和定位可信度。 相似文献
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介绍了RAIM算法中故障检测及其完好性保证的原理,采用STK仿真得到GPS和Galileo系统的卫星坐标及中国区域内的格网点坐标,结合航空用户对完好性需求,比较了GPS和Galileo系统下、不同类型导航性能需求的RAIM算法的可用性结果,分析了截止高度角、可视卫星数对故障检测可用性的影响。结果表明:当截止高度角越低、可视卫星数越多,故障检测的可用性越高;相同截止高度角条件时,Galileo系统下的RAIM可用性要高于GPS系统;单一的GPS导航系统难以满足垂直引导进近和精密进近等高等级的航空需求。 相似文献
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An Assessment of the RAIM Performance of a Combined Galileo/GPS Navigation System Using the Marginally Detectable Errors (MDE) Algorithm 总被引:1,自引:0,他引:1
W. Y. Ochieng K. F. Sheridan K. Sauer X. Han P. A. Cross S. Lannelongue N. Ammour K. Petit 《GPS Solutions》2002,5(3):42-51
Integrity relates to the trust that can be placed in the correctness of information supplied by a navigation system. It includes
the ability of the navigation system to provide timely warning to users when the system fails to meet its stated accuracy.
Specifically, a navigation system is required to deliver a warning (alarm) when the error in the derived user position solution exceeds an allowable level (alarm limit). This warning must be issued to the user within a given period of time (time-to-alarm) and with a given probability (integrity risk). The two main approaches to monitoring the integrity of satellite navigation systems are Receiver Autonomous Integrity Monitoring
(RAIM), and monitoring based on an independent network of integrity monitoring stations and a dedicated Ground Integrity Channel
(GIC). More recently Satellite Autonomous Integrity Monitoring (SAIM) methods have also been investigated.
This article presents the results of a study to assess the RAIM capability of the Galileo system when used alone and when
combined with the Global Positioning System (GPS). The assessment was based on the Marginally Detectable Error (MDE) algorithm.
The results show a significant improvement in the capability to perform RAIM using a combined Galileo/GPS system compared
to the performance using the Galileo system alone. This study was supported by Alcatel Space and was a contribution to the
Galileo definition studies carried out for the European Community under the GALA project. ? 2002 Wiley Periodicals, Inc. 相似文献
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The availability of GPS signals is a major concern for many existing and potential applications. Fortunately, with the development of Galileo by the European Commission (EC) and European Space Agency (ESA) and new funding for the restoration of the Russian GLONASS announced by the Russian Federation (Revnivykh et al., in European Navigation Conference 2005, Munich, Germany, July 19–22), the future for satellite-based positioning and navigation applications is extremely promising. With the complete cooperation from all these global navigation satellite systems (GNSS), greater levels of satellite visibility and therefore integrity can be expected. In this paper, a receiver autonomous integrity monitoring (RAIM) scheme along with reliability and separability measures are used to assess integrity performance levels of standalone GPS and integrated GPS/GLONASS, GPS/Galileo and GPS/GLONASS/Galileo systems where the clock offsets for each of the additional systems are estimated. It is shown, herein, that a minimum of three satellites must be visible in an additional system in order to provide a full integrity contribution when the system’s clock offset is to be estimated within the adjustment. A comparison of the integrity results obtained via system clock offsets estimated in the adjustment versus the case where the offsets are known and the measurements are corrected prior to the adjustment is also made for a high elevation mask scenario. Global simulation results for combined GPS/GLONASS/Galileo show that, theoretically, for the time of simulation and for any point on the globe, an outlier of 20 m can be detected with 80% probability at the 0.5% significance level and then separated from any other measurement with 90% probability. Corresponding values for the GPS only and combined GPS/GLONASS and GPS/Galileo systems, respectively, are approximately 435, 110 and 28 m, respectively, for the maximum MSBs and 312, 50 and 26 m, respectively, for the maximum MDBs. Temporal 24 h simulations for the GPS/GLONASS/Galileo scenario delivered agreeable results with the global snapshots for a 15° elevation mask. For the case where system clock offsets are estimated within the adjustment, it was shown that only the reliability measure was available for 100% of the time, with horizontal external reliability values of no more than about 12 m when a 30° masking angle was used. By assuming the clock offsets were determined and corrected for prior to the adjustment, the separability measure was markedly improved and was also available 100% of the time. 相似文献