共查询到19条相似文献，搜索用时 203 毫秒
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随着北斗卫星导航系统(BDS)全球组网进程的推进,BDS/GPS组合导航成为提高导航性能的重要方法,同时地基增强系统(GBAS)作为实现精密导航的新一代导航方式是当前研究的热点。本文通过推导BDS/GPS双系统组合GBAS数学模型,分别对BDS、GPS独立作为GBAS导航源及BDS/GPS组合导航作为GBAS导航源时系统的精度因子(DOP)、垂直保护级(VPL)性能进行了对比分析,对比验证了应用各系统时GBAS性能的差异。结果表明,基于BDS与GPS的GBAS性能接近,且互有优势;BDS/GPS组合GBAS性能优于各单系统性能。 相似文献
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卫星着陆系统(GLS)作为先进的航空新技术,其主要功能是为终端区精密进近的机载设备提供信号修正增强服务,为实现整个系统高精度离场和精密进近的功能发挥着重要作用. GLS完好性是终端区进近着陆引导应用的重要参数,是可靠性的重要依据,然而目前普通用户只关注导航定位的精度而没有考虑定位结果的可靠性,航空导航领域的机载对定位结果的可靠性要求极高,因此针对完好性故障监测性能展开研究分析,提出了一种接收机钟差调整策略并对其有效性进行仿真验证,并验证了完好性故障排除及未排除两种情况对定位精度及完好性的影响,进而证明完好性故障监测可保障GLS的系统性能、运行能力和安全性能达到预期要求. 相似文献
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基于伪卫星的改善GPS几何精度因子的研究 总被引：1，自引：1，他引：0
随着人们活动范围的日益扩大和周边环境的日益复杂,高精度GPS导航技术逐渐成为国内外研究的重点。GPS系统的定位精度在很大程度上取决于参与定位卫星的数目和几何布局,而几何精度因子(GDOP)正是衡量定位卫星几何布局优劣的量度。文章从几何精度因子着手,从理论上证明了伪卫星对GPS系统GDOP的改善,分析了伪卫星数量对GPS系统定位精度的影响。借助于仿真实验,结果表明,在GPS导航定位中,伪卫星能够显著增强卫星几何图形结构、提高测量精度、改善精度因子从而提高定位精度。 相似文献
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针对GNSS系统在可用性、安全性和完好性等方面的不足,在对伪卫星使用模式和关键技术进行系统归纳梳理的基础上,提出了广义伪卫星的概念和基于广义伪卫星的新一代GNSS增强系统框架。通过新设计的伪卫星体制,可以实现信号层、信息层和通信能力的全面增强,并将伪卫星的应用范围拓展至各类载体平台,实现了卫星导航信号的增强和延伸,提升了卫星导航系统的可用性、安全性、完好性和精确性。结合伪卫星的应用,本文提出了广义伪卫星的两种物理实现架构和组网同步模式,为广义伪卫星的推广应用奠定了技术基础。 相似文献
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针对生命安全用户对导航系统高完好性服务能力的迫切需求,以及国际航空完好性服务竞争日趋激烈的现状,北斗全球卫星导航系统一体化设计和规划了北斗星基增强系统(BDSBAS)。该文从国际民航组织(ICAO)相关标准要求,对BDSBAS服务性能进行研究和分析,推导并论证了系统精度、完好性、连续性等主要指标的分解方法;在此基础上,仿真计算了BDSBAS不同航空完好性服务等级对北斗系统等效伪距测量误差(UERE)、卫星故障概率、虚警概率等方面性能的要求。相关研究与分析结果能够为北斗及BDSBAS工程建设提供有益参考和借鉴。 相似文献
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接收机自主完好性监测(receiver autonomous integrity monitoring,RAIM)是终端用户高可靠导航定位的保障,低轨卫星的发展为完好性监测带来新的机遇,然而不同低轨星座增强下的终端RAIM性能可能会存在显著差异。基于高轨道倾角(80颗)、中轨道倾角(120颗)和混合轨道倾角(168颗)3种典型的低轨星座,系统评估了低轨卫星增强下的北斗卫星导航系统（BeiDou navigation satellite system,BDS）RAIM可用性及故障检测效果。仿真计算结果表明：对于高纬区域,高轨道倾角增强下的RAIM可用性效果最好,而在中、低纬区域,中轨道倾角星座增强下的RAIM可用性效果最优;在全球范围内,高轨道倾角、中轨道倾角和混合轨道倾角星座增强下非精密进近阶段的RAIM可用性较BDS分别提升30.5%、29.0%和41.0%。由此可知,由不同轨道倾角组成的混合星座可较好地弥补可视卫星在空间覆盖上的缺陷,其全球RAIM可用性增强效果最优,增强下的RAIM可检测到的最小伪距偏差较之前平均减小33.3 m。 相似文献
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现阶段整星座低轨卫星观测数据的缺失制约了LEO卫星导航增强研究,针对该问题,本文设计了LEO导航增强星座地基观测仿真系统,构建生成了LEO星座伪距和载波相位观测值的仿真模型;介绍了仿真系统设计流程和架构、仿真地基LEO观测数据;使用RTKLIB进行了标准单点定位（SPP）和精密单点定位（PPP）解算,验证了仿真系统搭建的正确性,以及伪距和载波观测值仿真的正确性。结果表明,相较于只考虑几何距离的地基观测数据,该系统考虑各误差模型后观测数据置信度高,可用于支撑LEO导航增强星座定位研究。 相似文献
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为了提高GPS卫星导航系统服务性能,很多国家和地区建立了独立的星基增强系统(SBAS),通过提供广播星历差分与完好性增强信息,满足高精度高完好性用户使用需求。本文介绍了美国WAAS和欧洲EGNOS等星基增强系统的广播星历差分完好性信息电文编码格式,并对实际星基增强系统的广播星历差分与完好性电文进行解析。由于不同的星基增强系统采用的信息处理模式不同,针对WAAS和EGNOS两个不同地区建立的星基增强系统,对广播星历差分慢变改正／快变改正的变化特征进行了比较分析。研究了星基增强系统广播星历差分完好性信息用户使用算法,基于国际GNSS服务组织(IGS)提供的GPS实测数据,对WAAS系统和EGNOS系统的广播星历差分服务精度和完好性性能进行了对比分析。结果表明,WAAS系统的伪距单点定位精度约为1.2 m, EGNOS系统的伪距单点定位精度约为1.8 m,与GPS基本导航服务相比,伪距单点定位精度可提高约22％和16％。两个星基增强系统利用完好性电文计算的完好性保护限值大致相当,均在16 m以内,能够对定位误差进行包络。 相似文献
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A global navigation satellite system augmentation system availability analysis tool has been developed to simulate a ground-based augmentation system (GBAS) prototype, an integrity monitor test bed, to evaluate its operational benefits at an airport of interest. The proposed availability simulation tool includes all GBAS ground facility algorithms as well as a graphical user interface that allows the user to modify simulation options and parameters. The output of the simulation tool is presented in a Stanford chart to help visualize the performance. The chart indicates the availability and integrity. The performance is evaluated primarily in the vertical position domain because of the weaker satellite geometry and more stringent required navigation performance as compared to those of the horizontal position domain. The simulation tool is implemented in Qt (http://www.qt.io/), an open-source cross-platform toolkit, allowing the tool to run on various devices. The computations are performed in the associated C++ code. The Newark Liberty International Airport (ICAO code: KEWR) is used as a simulation example to demonstrate the utility of the developed tool for investigating how reduced error models impact GBAS availability at the airport. 相似文献
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Approach service type D evaluation of the DLR GBAS testbed 总被引：3，自引：2，他引：1
Ground-based augmentation systems (GBAS) for satellite navigation are intended to replace the instrument landing system for precision approach of aircraft into an airport in the near future. Here, we show an evaluation of data collected during flight trials with the GBAS testbed of the German aerospace center with respect to requirements for the GBAS approach service type D. This service will permit approach and landing down to the zero visibility conditions of category IIIc approaches. We show output of all airborne monitors and the results of an integrity analysis. During all flight trials, the system performed within the required criteria for integrity, continuity, and availability. 相似文献
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In this paper, we present the development of a local area differential GPS testbed of the ground-based augmentation system (GBAS) as the future airport navigation facility in the Taipei Flight Information Region (FIR) in Taiwan. The testbed is mainly a GBAS ground facility, which consists of a ground station, three GBAS receivers, and a VDL (VHF data link) broadcast antenna. We also present an airborne GPS/GBAS prototype receiver in this paper. The airborne subsystem (a GPS/GBAS receiver) receives the correction messages from the ground subsystem to perform a differential GPS (DGPS) positioning. In order to provide an ILS-look-alike approach and landing, the output messages of the airborne receiver are packed in an ARINC 429 format. The proposed airborne system has a software-based global navigation satellite system (GNSS) receiver structure. 相似文献
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Prediction and analysis of GBAS integrity monitoring is important, especially at the airports where a GBAS station it to be installed. Based on existing standard documents and published research, we present a software tool for GBAS availability prediction. Simulations have been conducted that include single point, single approach path, and multiple repetitions of a same approach path in order to analyze the availability of GNSS signal integrity monitoring with a GBAS at LinZhi airport. The results show that the long-term 24-h service availability figure at two typical single points along the approach path for GBAS Approach Service Type C (GAST C) is above 99.999 % for each point, and for GBAS Approach Service Type D (GAST D) at three typical single points, it is lower than 99.8 % for each point. The unavailability percentage over a 24-h period is 0.76 and 2.40 % for GAST C and GAST D, respectively. The results of sensitivity tests show that the impact of the mask angle and the latitude on the GBAS availability at LinZhi airport are more important than that of the constellation. Our conclusions could also be of interest for the implementation of GBAS stations at other plateau airports. 相似文献
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北斗全球卫星导航系统(简称北斗三号系统,BDS-3)的建设对拓展全球卫星导航系统(global navigation satellite system, GNSS)的应用有重要作用,为多星座融合定位、导航和授时提供了重要支持。多系统融合定位给用户提供了更多的导航信息源,也为导航卫星系统完好性和用户自主完好性指标的实现提供了新的保障。然而多卫星组合的使用显著增加了观测冗余信息,由此提出一种基于抗差估计的保护水平重构方法,利用抗差估计方法及其参数验后信息,重新估计用户保护水平。利用GPS/BDS组合数据进行计算分析,实验结果表明,该方法可在保障特定要求定位精度的前提下,降低告警频率。 相似文献
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Ionospheric disturbances present a considerable hazard to single-frequency satellite navigation systems for airborne users. We discuss our implementation of three ionospheric threat models in the DLR “multi-output advanced signal test environment for receivers” global navigation satellite system simulator, which is based on Spirent GSS 7780/7790 signal generator. These threat models include the standard front-based threat model developed for the integrity assessment of ground-based augmentation systems (GBAS), a simplified plasma bubble model, and ionospheric scintillation, which can be combined with either of the two previously mentioned models. These effects can now straightforwardly be simulated at the German Aerospace Center’s research facilities. As an example, we simulate a GBAS ground facility with code–carrier divergence monitoring, affected by an ionospheric front, and we show the results of a simulation with coincidental occurrence of a plasma bubble and scintillation with an S 4 index of 0.4. 相似文献
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针对民航飞机利用陆基增强系统(GBAS)进行精密进近着陆过程中,GBAS机载甚高频数据广播(VDB)接收机所受到的同频干扰问题,提出采用盲信号分离算法,对VDB接收机所接收到的期望信号与同频干扰信号进行分离,并通过识别解码数据中的机场标识(ID),得到所需期望信号,从而抑制同频干扰信号. 分析并仿真了基于快速固定点(Fast ICA)算法、自然梯度算法和等变自适应分离(EASI)算法,对VDB接收机接收到的混合信号进行分离的机理和同频干扰抑制的实现. 仿真结果表明,这三种算法均能有效分离期望信号与同频干扰信号,进而进行同频干扰抑制,并通过比较三种算法的收敛速度、串音误差和误码率,得出 Fast ICA算法更适合用于VDB信号的同频干扰抑制. 相似文献