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RAIM是指用户接收机利用多余观测量为定位解自主地提供完善性监测,其基本功能包括故障检测(FD)及故障排除(FE)两个部分。文中对基于奇偶矢量法的GPS接收机自主完善性监测(RAIM)算法进行分析与研究,并以具体数据为例,对该算法进行验证分析。 相似文献
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针对目前GPS接收机自主完好性监测方法受到许多假设的制约这一问题,该文根据已有的导航系统可靠性研究,基于非理想故障模式以及故障分布参数的不确定性,利用先验概率模型对卫星和接收机异常建模;采用该模型,建立了基于误警率及漏检率的最小风险代价任意目标函数,以对残差统计量分析进而优化选取阈值;最后对快照接收机自主完好性监测法以及利用贝叶斯更新得到后验故障概率的多步完好性监测算法进行分析,具有一定的参考意义,多步算法将会进一步丰富GPS完好性结构。仿真实验结果表明,在每个几何条件下用反复试验法可进行阈值的搜索,达到比传统接收机自主完好性监测方法更好的效果。 相似文献
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接收机自主完好性监测(RAIM)是卫星导航系统完好性监测的方法之一。一定时空条件下的RAIM可用性,可以通过RAIM空洞直观的反映出来,可以为飞行提供预警;利用不同期GPS、GLONASS实际星座,仿真分析了单星座以及GPS/GLONASS组合星座RAIM可用性,绘制了RAIM空洞图,具有一定的参考价值。 相似文献
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One of the key approaches to monitor the integrity of Global Satellite Navigation Systems (GNSS) is receiver autonomous integrity monitoring (RAIM). Existing RAIM algorithms utilise two tests in the position domain (for RAIM availability) and measurement domain (for failure detection). This paper proposes an alternative RAIM algorithm, which is based entirely in the measurement domain. This algorithm can be used for sensitivity analyses to support performance specification and system design. It can also be used during actual flight operations where the trigger is the phase of flight and its required navigation performance (RNP) parameters. This is made possible by computationally efficient calculation of the chi-squared parameters. The algorithm reverts to the current approach if the phase of flight is unknown. Simulation results for non-precision approach (NPA) have been used to demonstrate the effectiveness of the proposed algorithm. 相似文献
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把导航领域、军事领域和导航电子地图中广泛应用的圆概率误差(circular error probable,CEP)引入到HPL(horizontal protection level)的计算中,在最小二乘残差法基础上构建了基于圆概率误差的RAIM(receiver autonomous integrity monitoring)可用性算法。首先计算了在一定误警率、漏警率条件下多颗卫星发生故障时的水平定位偏差和一定置信度下的圆概率误差;然后以GPS导航星座为例,探讨了相关观测下计算HPL的新方法;最后把HPL与水平告警限差(horizontal alert limit,HAL)相比较,得到了基于圆概率误差的RAIM可用性,并通过算例验证了此方法的有效性和可行性。 相似文献
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针对基于最小二乘残差估计的接收机自主完好性监测(RAIM)算法,结合伪距单点定位多采用观测量非等权模型,提出一种观测量非等权模型RAIM可用性算法,对实际计算具有借鉴意义。通过实测数据,分析了等权模型和非等权模型RAIM可用性算法对卫星几何分布的估计情况,验证了观测量非等权模型RAIM可用性算法的可行性。 相似文献
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针对GNSS接收机在室内环境中面临的强烈的信号衰减、非视距传播和互相关效应的问题,提出了一种基于粗时段导航和RAIM算法解决A-GNSS室内定位问题的方法,并利用BDS数据验证了该方法的可靠性。结果表明,粗时段导航算法能够提供连续可靠的定位结果,应用于微弱信号环境;基于组合FDE的RAIM算法能够增加定位结果可用率,解决室内卫星信号存在的非视距传播和互相关效应的问题。基于粗时段导航与RAIM算法的A-GNSS定位技术能够应用于室内定位,仿真定位结果水平方向RMS在10 m以内。 相似文献
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Measurements consistency-based Receiver Autonomous Integrity Monitoring (RAIM) is the main technique for monitoring the integrity of global satellite navigation systems at the user-level. Existing RAIM algorithms utilize two tests, in the position domain a test for RAIM availability and in the measurement domain a test for failure detection. These tests involve the computation of three parameters: test statistic, decision threshold, and protection level. The test statistic is based on the actual measurements in the form of the sum of the squared errors (SSE). The decision threshold is chosen on the basis of the statistical characteristics of the SSE including the assumption that the errors are normally distributed. However, in practice residual, error distributions exhibit heavier tails than predicted by the Gaussian model. Therefore, this paper challenges the normality assumption of the residual navigation errors in three ways. First, real data are used to assess its impact on the traditional RAIM algorithm. Second, extreme value theory is applied to the tails, and the generalized extreme value (GEV) distribution is derived to capture residual navigation errors. Third, the performance of the traditional RAIM approach is compared with that employing the GEV distribution. The results demonstrate that the GEV model is a more accurate representation of the distribution of residual navigation errors than the conventional Gaussian model and should be used in the development of integrity monitoring algorithms. 相似文献
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鉴于独立分量对异常值具有较强的敏感性,提出了基于独立分量分析(ICA)的伪距多变量时间序列异常值探测算法,并且利用契比雪夫不等式给出了异常值探测的阈值,引入时间序列干预模型估计了潜在故障扰动的大小,根据3σ准则确定出故障星的位置。根据RAIM的实时性要求,采用滑动窗口的思想对上述批处理探测算法进行改造,本文提出了一种卫星多故障在线探测和识别的新算法,并给出了新RAIM算法的实施流程。利用5个iGMAS北斗监测站的民用观测数据对新算法进行验证,试验分析结果表明,新算法对于卫星多故障的实时处理具有较好的效果,且其故障正确探测率优于以往的RANCO方法。 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