共查询到17条相似文献，搜索用时 93 毫秒
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《武汉大学学报(信息科学版)》2021,(6)
为了解决电离层扰动和低高度角下非差数据的实时周跳探测与修复问题,提出了一种基于TurboEdit历元差模型的优化算法。首先在无几何距离组合历元差中加入滑动多项式拟合法提取电离层延迟与多路径效应误差的趋势项,通过选择合适的阈值,增强对小周跳的探测能力;然后针对历元差模型无法区别周跳与粗差的问题,引入统计诊断中的Score检验量并构建了基于Score检验的周跳与粗差分离模型,避免了粗差引起的周跳误探现象;最后在成功探测出周跳后,使用探测量最小1范数准则来选取正确的周跳修复值。采用国际GNSS服务站GPS非差数据对所提算法进行验证,实验结果表明,该优化算法能够有效抑制低高度角时的多路径效应和电离层延迟误差,实时剔除粗差并准确修复周跳,对小周跳具有较高的探测灵敏度与较低的误判率。 相似文献
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BDS三频观测条件下可以组合得到具有优良特性的虚拟载波观测量,有利于改善非差观测数据的周跳实时探测与修复。文中提出一种基于BDS三频非差数据的周跳实时探测与修复模型:首先,采用消电离层无几何HMW组合观测量探测和修复EWL周跳;然后,将经过修复的EWL观测量与WL组合消除几何相关项,忽略电离层延迟残差进而确定WL周跳;最后采用经过修复的WL观测量与NL组合形成无几何观测量,并通过优化载波相位组合确定电离层延迟的变化量以探测和计算NL周跳,并通过简单变换得到原始载波观测量的周跳值。通过实测BDS三频数据对模型可行性进行验证分析,结果表明,即使在30s的采样率以及电离层活动活跃条件下,该模型都可有效实时探测和修复各类周跳。 相似文献
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基于伪距相位和STPIR组合的北斗三频周跳探测与修复 总被引：1，自引：0，他引：1
GNSS周跳探测中,电离层残差法的适用性受数据采样间隔的影响较大,同时联合其它组合观测量进行周跳修复时,周跳修复方程组易出现病态解。针对这些问题,文中提出一种可靠的北斗三频周跳探测与修复算法,通过构造北斗三频电离层残差组合观测量,进行二阶历元间差分,基于三频伪距相位组合优选理论,选取适用于北斗三频数据的伪距相位组合,结合两种组合观测量,优选条件数较小的组合系数矩阵进行周跳修复,最后通过北斗三频实测数据验证,结果表明:在数据采样间隔较大的情况下,利用构建的三个组合观测量可以探测出北斗三频原始数据中的所有周跳,具有很好的修复效果。 相似文献
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A new automated cycle slip detection and repair method for a single dual-frequency GPS receiver 总被引：12，自引：2，他引：10
Zhizhao Liu 《Journal of Geodesy》2011,85(3):171-183
This paper develops a new automated cycle slip detection and repair method that is based on only one single dual-frequency
GPS receiver. This method jointly uses the ionospheric total electron contents (TEC) rate (TECR) and Melbourne–Wübbena wide
lane (MWWL) linear combination to uniquely determine the cycle slip on both L1 and L2 frequencies. The cycle slips are inferred
from the information of ionospheric physical TECR and MWWL ambiguity at the current epoch and that at the previous epoch.
The principle of this method is that when there are cycle slips, the MWWL ambiguity will change and the ionospheric TECR will
usually be significantly amplified, the part of artificial TECR (caused by cycle slips) being significantly larger than the
normal physical TECR. The TECR is calculated based on the dual-frequency carrier phase measurements, and it is highly accurate.
We calculate the ionospheric change information (including TECR and TEC acceleration) using the previous epochs (30 epochs
in this study) and use the previous data to predict the TECR for the epoch needing cycle slip detection. If the discrepancy
is larger than our defined threshold 0.15 TECU/s, cycle slips are regarded to exist at that epoch. The key rational of method
is that during a short period (1.0 s in this study) the TECR of physical ionospheric phenomenon will not exceed the threshold.
This new algorithm is tested with eight different datasets (including one spaceborne GPS dataset), and the results show that
the method can detect and correctly repair almost any cycle slips even under very high level of ionospheric activities (with
an average Kp index 7.6 on 31 March 2001). The only exception of a few detected but incorrectly repaired cycle slip is due
to a sudden increased pseudorange error on a single satellite (PRN7) under very active ionosphere on 31 March 2001. This method
requires dual-frequency carrier phase and pseudorange data from only one single GPS receiver. The other requirement is that
the GPS data rate ideally is 1 Hz or higher in order to detect small cycle slips. It is suitable for many applications where
one single receiver is used, e.g. real-time kinematic rover station and precise point positioning. An important feature of
this method is that it performs cycle slip detection and repair on a satellite-by-satellite basis; thus, the cycle slip detection
and repair for each satellite are completely independent and not affected by the data of other satellites. 相似文献
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周跳探测与修复是高精度动态GPS定位的关键技术之一,直接影响模糊度在航解算的效率。针对动态相对定位中周跳探测方法“三差法”的不足,提出一种基于站际历元二次差模型进行探测与修复周跳的新方法。首先对站际历元间二次差观测值进行粗差探测,以确定发生周跳的卫星以及周跳初值;然后基于残差平方和最小原则搜索周跳备选组合并修复周跳。理论分析和实验结果均表明,当有效共视卫星多于4颗时,大多数情况下,新方法可以准确定位并修复周跳。 相似文献
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Cycle slip detection and repair for undifferenced GPS observations under high ionospheric activity 总被引：3，自引：3，他引：0
We develop a new approach for cycle slip detection and repair under high ionospheric activity using undifferenced dual-frequency GPS carrier phase observations. A forward and backward moving window averaging (FBMWA) algorithm and a second-order, time-difference phase ionospheric residual (STPIR) algorithm are integrated to jointly detect and repair cycle slips. The FBMWA algorithm is proposed to detect cycle slips from the widelane ambiguity of Melbourne–Wübbena linear combination observable. The FBMWA algorithm has the advantage of reducing the noise level of widelane ambiguities, even if the GPS data are observed under rapid ionospheric variations. Thus, the detection of slips of one cycle becomes possible. The STPIR algorithm can better remove the trend component of ionospheric variations compared to the normally used first-order, time-difference phase ionospheric residual method. The combination of STPIR and FBMWA algorithms can uniquely determine the cycle slips at both GPS L 1 and L 2 frequencies. The proposed approach has been tested using data collected under different levels of ionospheric activities with simulated cycle slips. The results indicate that this approach is effective even under active ionospheric conditions. 相似文献
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常规全球卫星导航系统（GNSS）周跳探测方法大多忽略了高度角对多路径误差以及观测噪声的影响．由于海上GNSS浮标的数据质量受海面影响很大,在卫星高度角降低时其观测噪声和多路径误差显著增大,且具有高频周跳特点,常规GNSS周跳探测方法并不适用．据此,提出了一种综合电离层总电子含量变化率（TECR）和顾及高度角加权阈值模型的改进双频码相组合（MW）探测法的周跳探测与修复方法．实验结果表明:该方法能有效抑制低高度角和多路径影响带来的信号噪声,准确探测到各种类型周跳,可有效应用于海上GNSS浮标的数据预处理. 相似文献
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提出了一种适用于实时GPS精密单点定位的周跳探测与修复的新算法。该算法步骤为：①利用M-W组合和电离层残差组合初步确定没有发生周跳和可能发生周跳的卫星;②利用当前历元与前一（或几个）历元的L1、L2和Lw观测值和第一步得出的没有发生周跳的卫星信息,采用基于历元间差分观测值的周跳处理模型对可能发生周跳的卫星进行周跳探测;③对第二步中周跳处理失败的卫星进行进一步的精化处理,以尽可能修复周跳。实验表明,新算法在实时GPS精密单点定位中可以准确地探测并修复周跳。 相似文献
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Processing of data from global navigation satellite systems (GNSS), such as GPS, GLONASS and Galileo, can be considerably impeded by disturbances in the ionosphere. Cycle-slip detection and correction thus becomes a crucial component of robust software. Still, dealing with ionospheric cycle slips is not trivial due to scintillation effects in both the phase and the amplitude of the signals. In this contribution, a geometry-based approach with rigorous handling of the ionosphere is presented. A detailed analysis of the cycle-slip correction process is also tackled by examining its dependence on phase and code noise, non-dispersive effects and, of course, the ionosphere. The importance of stochastic modeling in validating the integer cycle-slip candidates is emphasized and illustrated through simulations. By examining the relationship between ionospheric bias and ionospheric constraint, it is shown that there is a limit in the magnitude of ionospheric delay variation that can be handled by the cycle-slip correction process. Those concepts are applied to GNSS data collected by stations in northern Canada, and show that enhanced cycle-slip detection can lead to decimeter-level improvements in the accuracy of kinematic PPP solutions with a 30-s sampling interval. Cycle-slip correction associated with ionospheric delay variations exceeding 50 cm is also demonstrated, although there are risks with such a procedure and these are pointed out. 相似文献