共查询到16条相似文献，搜索用时 125 毫秒
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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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针对历元间隔较大或电离层延迟较大的情况,采用两个无几何相位组合与一个最优无几何无电离层组合形成3个线性无关的探测量,将历元间高次差法引用到无几何相位组合探测量中,通过选取合适的探测阈值,使无几何相位组合能够正确探测到较大电离层影响情况下的不敏感周跳。此外,文中采用了一种特殊的无几何无电离组合观测量进行辅助修复,通过两次取整保证了周跳修复的准确性,避免了传统三频周处理中的搜索算法造成错误修复的问题,试验表明,文中算法可以正确探测与修复较大电离层影响情况下不同北斗卫星星座类型的所有小周跳组合以及不敏感周跳组合。 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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《武汉大学学报(信息科学版)》2016,(12)
结合我国北斗导航卫星系统的特点,通过对三频数据进行线性最优组合来有效探测和修复各类周跳。应用了5种线性几何无关组合并基于三步法进行周跳探测。对于探测到的不同周跳,通过特定的三频载波相位线性组合进行有效的分辨和修复,最后基于北斗三频实测数据,针对不同电离层延迟变化水平,分别就1s、15s、30s不同采样间隔下的周跳探测和修复能力进行了验证,取得了较优的结果。 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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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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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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Dezhong Chen Shirong Ye Wei Zhou Yanyan Liu Peng Jiang Weiming Tang Bing Yuan Lewen Zhao 《GPS Solutions》2016,20(3):439-450
The difficulty to detect and repair cycle slip of carrier phase measurements is a key limit for continuously high accuracy of GNSS positioning and navigation services. We propose an automated cycle slip detection and repair method for data preprocessing of a CORS network. The method jointly uses double-differenced (DD) geometry-free (GF) combination and ionospheric-free observation corrected for the computed geometrical distance (IF-OMC) to estimate the cycle slips in dual-frequency observations. The DD GF combination, which is only affected by the ionospheric residual, can be used to detect cycle slips with high reliability except for special pairs such as (77, 60) on GPS L1/L2 frequencies. The detection principle of the IF-OMC observable is such that there is a large discontinuity related to the previous epoch when cycle slips occur at the present epoch. The disadvantages of these two combinations can be overcome employing the proposed detection method. The cycle slip pair (77, 60) has no effect on the GF combination, while a change of 14.65 m is derived from GPS L1/L2 observations using the IF-OMC algorithm. Using pre-determined station coordinates as precise values, we found that the accuracy of the DD IF-OMC combination was 18 mm for a 200-km CORS baseline. Therefore, cycle slips in dual-frequency observations can be correctly and uniquely determined using DD GF and IF-OMC equations. The proposed method was verified by adding simulated cycle slips in observations collected from the CORS network under a quiet ionosphere and shown to be effective. Moreover, the method was assessed with observations made during intense ionospheric activity, which generated extensive cycle slips. The results show that the algorithm can detect and repair all cycle slips apart from two exceptions relating to long data gaps. 相似文献
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利用改进的TurboEdit算法与Chebyshev多项式探测与修复周跳 总被引：1，自引：0，他引：1
根据利用TurboEdit方法对GPS观测数据进行周跳探测的特点,设计了固定弧段长度的滑动窗口拟合模型,对其中的Geometry-Free组合法进行改进;在探测出周跳后,利用最小二乘Chebyshev多项式拟合来修复周跳。实验结果表明,改进后的TurboEdit算法可以探测出等周的1周小周跳、等周的大周跳和连续的小周跳、大周跳,同时,最小二乘Chebyshev多项式拟合可以精确修复以上周跳对。 相似文献
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建立了GPS/INS紧组合定位模型,改正惯性器件误差及电离层折射误差,对不同组合观测量的误差影响进行了分析,构造不同观测值组合,提出了基于惯性信息辅助的GPS周跳自适应探测方法,分析了INS定位误差对周跳探测的影响,给出了周跳探测误报率及修复成功率评价指标,提出了一种周跳检测阈值自适应确定方法。利用实测组合导航试验数据验证本文的算法,文中模拟了不同的单历元多周跳及信号失锁条件,结果表明,在GPS信号完全失锁20 s内,该方法能准确检测和修复所有周跳,中断时间的延长降低了周跳修复的成功率;GPS信号部分失锁时,在模拟的90 s中断时段内仍能修复所有周跳;模拟了170历元的5 s间隔密集周跳,周跳探测成功率为100%,正确修复率为99.41%。 相似文献