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基于小波变换的周跳探测与修复 总被引:2,自引:1,他引:1
探测和修复周跳一直是GPS定位中的关键问题。利用小波变换对相位减伪距观测量进行周跳探测。首先介绍小波变换周跳探测的一般方法,然后在此基础上提出改进。改进方法可以对周跳进行探测和直接修复,进而探测和修复多次周跳,同时有效地克服一般方法可能出现探测失误的缺点。这种改进方法的效果在实验中得到验证。 相似文献
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针对北斗三频信号,引入了惯性信息辅助周跳探测与修复,建立了北斗/INS松组合模型,提高了多径误差严重影响下的BDS周跳探测成功率和修复率。在常规伪距-相位组合与几何无关组合探测三频周跳的基础上,提出了INS定位辅助的北斗三频组合法,构建了INS辅助的周跳决策量,分析了INS定位误差对周跳探测的影响。该方法克服了周跳探测受伪距观测值精度影响的不足,实现了北斗系统多径环境中的小周跳探测。试验采用船载INS/BDS三频组合系统进行数据实测分析,结果表明,在水面强多径噪声环境导致传统三频探测模型失效的情况下,该方法显著提高了探测成功率与修复率,并适用于低频北斗观测数据。 相似文献
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周跳的探测与修复是GPS载波相位数据处理中一项重要的任务。首先介绍了双频相位求差法探测与修复周跳的原理;其次,利用Fortran语言编制了相应的程序,并通过实例分析了在不同采样率下探测周跳与修复的效果;最后讨论了该方法探测周跳的不足。 相似文献
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A. El-Mowafy 《GPS Solutions》2014,18(4):553-561
A method is presented for real-time validation of GNSS measurements of a single receiver, where data from each satellite are independently processed. A geometry-free observation model is used with a reparameterized form of the unknowns to overcome rank deficiency of the model. The ionosphere error and non-constant biases such as multipath are assumed changing relatively smoothly as a function of time. Data validation and detection of errors are based on statistical testing of the observation residuals using the detection–identification–adaptation approach. The method is applicable to any GNSS with any number of frequencies. The performance of validation method was evaluated using multi-frequency data from three GNSS (GPS, GLONASS, and Galileo) that span 3 days in a test site at Curtin University, Australia. Performance of the method in detection and identification of outliers in code observations, and detection of cycle slips in phase data were examined. Results show that the success rate vary according to precision of observations and their number as well as size of the errors. The method capability is demonstrated when processing four IOV Galileo satellites in a single-point-positioning mode and in another test by comparing its performance with Bernese software in detection of cycle slips in precise point-positioning processing using GPS data. 相似文献
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GPS/BDS中长距离RTK定位因为电离层和对流层残余误差的影响,其性能相对于常规RTK有所降低。将GPS/BDS卫星双差电离层误差和对流层误差作为参数,采用卡尔曼滤波进行实时估计。为了验证算法的有效性,利用武汉地区103 km静态基线24 h双频观测数据,分析了GPS和BDS单系统以及二者组合双系统中长距离RTK定位性能。实验结果表明,精确估计的双差电离层残余误差达到米级、对流层误差达到分米级;经过改正后,GPS/BDS单系统的定位精度在1 cm左右,组合双系统则实现了中长距离基线毫米级的高精度定位。 相似文献
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摘要GPS精密单点定位技术已经发展成为GPS领域研究的热点之一。本文主要讨论了:情密单点定位的数学模型、误差处理理论和数据预处理等,并利用Matlab编程进行实验性验证,最终对静态单点:乏位分别采用双频载波相位平滑后的P码伪距组成消电离层组合的最小二乘估计和卡尔曼滤波估计进行处理,得到亚米级的定位结果。 相似文献
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This paper investigates the third-order residual range error in the dual-frequency correction of ionospheric effects on satellite
navigation. We solve the two-point trajectory problem using the perturbation method to derive second-approximation formulas
for the phase path of the wave propagating through an inhomogeneous ionosphere. It is shown that these formulas are consistent
with the results derived from applying perturbation theory directly to the eikonal equation. The resulting expression for
the phase path is used in calculating the residual range error of dual-frequency global positioning system (GPS) observations,
in view of second- and third-order terms. The third-order correction includes not only the quadratic correction of the refractive
index but also the correction for ray bending in an inhomogeneous ionosphere. Our calculations took into consideration that
the ionosphere has regular large-scale irregularities, as well as smaller-scale random irregularities. Numerical examples
show that geomagnetic field effects, which constitute a second-order correction, typically exceed the effects of the quadratic
correction and the regular ionospheric inhomogeneity. The contribution from random irregularities can compare with or exceed
that made by the second-order correction. Therefore, random ionospheric irregularities can make a significant (sometimes dominant)
contribution to the residual range error. 相似文献
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基于伪距相位组合实时探测与修复GNSS三频非差观测数据周跳 总被引:1,自引:1,他引:0
三频观测量能形成具有更长波长、更小噪声、更小电离层影响等优良特性的组合观测量,有利于提高周跳探测和修复的精度。本文推导了伪距相位组合探测周跳的阈值条件;提出了周跳确定成功率的概念;并从提高周跳确定成功概率出发,给出了伪距相位组合选取的标准和方法;最后利用一组实测GPS三频数据进行了验证。结果表明,在数据采样率较高、历元间电离层延迟变化可忽略时,根据文中提出原则选取的最优伪距相位组合可实时探测和修复三频非差观测数据中的所有周跳。 相似文献
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GPS现代化后电离层折射误差高阶项的三频改正方法 总被引:13,自引:1,他引:13
研究了电离层对GPS观测信号的主要影响及电离层折射误差模型,总结了电离层双频改正模型。针对GPS现代化中增加的第三频率,系统推导了三个频率的电离层改正模型及相位观测值无电离层组合(LC组合)模型。该模型将电离层折射误差模型改正至二阶项,可进一步提高GPS定位精度,同时,为GPS定位中其他误差的改正及分离、周跳的探测等提供了有力的技术手段。 相似文献
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硬件延迟是利用GPS进行TEC测量时最大的误差源,其影响可达30多TECU。为获得更准确的绝对TEC数值,必须利用一定的电离层模型计算得出GPS系统硬件延迟。本文为估算利用一个时段内的观测数据计算得出的硬件延迟对后续时段TEC测量的影响,利用IGS网络中60多个数据质量良好的GPS跟踪站数据,对硬件延迟的精度和稳定性进行了研究。结果表明:GPS系统硬件延迟在短期内具有较好的精度和稳定性,但是当发生电离层扰动现象时GPS系统硬件延迟的精度和稳定性会遭到破坏。同时根据GPS系统硬件延迟稳定性的研究成果,本文还提出了一种对太阳耀斑进行预报的观点。 相似文献