共查询到19条相似文献,搜索用时 218 毫秒
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动态变形监测多路径实时修正模型研究 总被引:5,自引:1,他引:4
多路径效应是GPS高精度实时动态变形监测中的主要误差源,通过经验模态分解方法对三维坐标序列进行多尺度分解和重构,提取作为趋势项的多路径模型;并利用多路径效应的周日强相关性特点,对第二天动态坐标进行多路径效应去除,得到削弱多路径效应后的坐标序列。研究结果表明,多路径效应削弱后的坐标序列稳定性明显增强,坐标的精度明显提高。 相似文献
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基于经验模态分解的GPS基线解算模型 总被引:1,自引:1,他引:0
非建模系统误差是影响高精度GPS基线解算精度的一个重要因素,文章给出基于经验模态分解的GPS基线解算模型,有效消弱系统误差对基线解的影响。在现有经验模态分解理论的基础上,定义经验模态分解的多尺度分解与重构结构,并由此给出基于经验模态的系统趋势分离模型,依据累积标准化模量的均值随尺度的变化确定系统误差与噪声分离尺度的选择标准。给出基于经验模态分解的GPS基线解算的技术路线,首先计算GPS相位双差观测方程的浮点解残差序列,分离出系统误差并用于修正GPS双差观测值,重新计算双差浮点解,采用Lambda算法固定整周模糊度,计算固定基线解,从而消弱系统误差对基线解算的影响,提高基线固定解的可靠性。并采用实测GPS数据验证模型,F-ratio指数与W-ratio指数表明系统误差消弱后,基线固定解可靠性得到明显提高,重新计算的残差序列表明系统误差得到很好的消弱。 相似文献
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多路径误差为一时空环境效应,难以构建准确数学模型消除其影响,且该误差在基线两端不具有空间相关性,运用现有差分技术也无法很好消除,是高精度短基线测量中主要误差之一.为进一步削弱多路径误差,本文以监测站坐标时间序列中多路径误差为研究对象,根据多路径误差在历元间的时变特性,建立多路径误差状态空间模型,采用标准卡尔曼滤波和顾及有色噪声的卡尔曼滤波从监测站第一天双差固定解坐标残差序列中估计多路径误差改正序列,并根据多路径误差的周日重复特性,利用第一天得到的多路径误差改正序列对之后各天坐标序列进行改正.最后通过实验分析,得出顾及有色噪声的卡尔曼滤波估计方法优于标准卡尔曼滤波的结论.研究方法对提高GNSS定位精度具有重要实用价值. 相似文献
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通过双差方法难以消除的多路径误差、接收机观测噪声等非模型化误差会大大影响GPS动态定位的精度.基于小波分析的理论,对GPS双差观测数据序列的消噪问题进行研究,结果表明,利用小波去噪原理,可有效地从受到强噪声干扰的GPS观测数据序列中提取变形特征信息,增强基线解算的有效性,提高GPS定位精度,解决传统技术对GPS动态监测... 相似文献
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桥梁变形观测中GPS数据处理方法的研究 总被引:1,自引:0,他引:1
对桥梁变形体利用GPS进行变形监测,并通过GPS接收机随机软件进行外业观测数据的解算,研究GPS数据处理中解算基线向量时观测历元、截止高度角参数的最佳设置方法及平差模型的选择,以提高解算精度,为其他同类工程提供一定的参考. 相似文献
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文章通过1HZ GNSS连续观测,设计了高楼结构振动动态监测试验方案:对连续多天观测数据进行了动态单历元解算;根据不同时段可视卫星的平均轨道周期,利用改进的恒星日滤波,减弱了多路径效应;在分析位移时间序列频谱的基础上,结合不同信号的时频特性,进行了高频滤波去噪;最后,成功提取了真实的高楼结构振动时间序列。研究结果表明,多天提取序列趋势一致,精度相当;每天位移时间序列变化较大的时段与地铁的运营时段相吻合;在有效消除多路径效应和随机噪声后,GNSS单历元监测高楼结构振动的精度为:水平方向±2mm,垂直方向±4mm。 相似文献
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《武汉大学学报(信息科学版)》2021,(6)
随着中国高铁的发展,全球导航定位系统(global navigation satellite system,GNSS)动态定位技术在列车定位及轨道检测中具有广阔的应用前景,但其精度目前难以满足轨道检测要求。多路径效应是影响GNSS动态定位精度的一个主要误差源,目前已有的多路径误差削弱方法大多适用于静态测量环境,尚无有效的方法削弱动态多路径误差。分别采用传统算法和以轨检几何信息作为约束条件的算法解算GNSS观测数据,并将受到多路径影响的测量结果与轨检信息进行对比分析,同时利用小波多尺度分解算法分离坐标残差序列中的多路径误差和噪声,得到"干净"的轨道坐标序列。实验结果表明,由于信息量增加,融合轨检信息的GNSS数据解算方法可以有效提取多路径误差和观测噪声;利用小波相关分析能进一步削弱坐标域中的多路径误差,提高GNSS动态定位的精度,满足高铁轨道测量的需求。 相似文献
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Michael Moore Christopher Watson Matt King Simon McClusky Paul Tregoning 《Journal of Geodesy》2014,88(9):887-900
Continuous global positioning system (GPS) stations propagate biases and spurious signals into the derived parameter time series when the measurements are subject to site-specific effects, such as multipath. This is a particular problem in the investigation of geophysical and atmospheric phenomena where signals may be small in magnitude. A methodology to remove these erroneous signals from long-term time series will significantly increase the usefulness of the derived time series. This work provides the theoretical basis for use of an empirical site model (ESM) derived from post-fit phase residuals to mitigate unmodelled site-specific errors. Additionally, we also investigate the effectiveness of applying an ESM to a regional GPS network and a short baseline solution. Under most observing scenarios, we show that the ESM approach is predicted to improve the precision and accuracy of the site coordinates. However, it is important to note that we found some scenarios where the ESM can introduce a bias. For instance, when the antenna is mounted close to the ground. In this scenario, for a short baseline, we observed the introduction of a 4-mm bias in height. Use of an ESM for the same short baseline with an uncalibrated radome substantially improves the results by removing a large bias of over 10 mm in height. Similarly, application of an ESM derived from historic data yields similar improvements. This demonstrates that the ESM can be a powerful tool when applied to appropriate site-specific configurations and could potentially be implemented in routine GPS analysis for a broad range of applications. 相似文献
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不同等级或分属不同区域的控制点间,以及由不同单位布设的控制点间可能存在较大的误差。若将这些存在较大误差的已知点作为平差计算或坐标转换的约束,其结果必然会扭曲GPS测量的原有精度,特别是当这些点误差较大或含有粗差时,将严重影响GPS成果的可靠性,使高精度的GPS定位成果失去其本来的意义。本文分别探讨了平差结果直接分析法、实测基线比较法、单位权方差假设检验法和附合路线坐标闭合差检验法等对GPS控制网起算数据进行兼容性分析的方法,并采用其中几种对GPS控制网起算数据进行具体分析和计算,剔除了含有粗差的已知点,保证了控制测量成果的精度和可靠性。 相似文献
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Multipath error is considered one of the major errors affecting GPS observations. One can benefit from the repetition of satellite
geometry approximately every sidereal day, and apply filtering to help minimize this error. For GPS data at 1 s interval processed
using a double-difference strategy, using the day-to-day coordinate or carrier-phase residual autocorrelation determined with
a 10-h window leads to the steadiest estimates of the error-repeat lag, although a window as short as 2 h can produce an acceptable
value with > 97% of the optimal lag’s correlation. We conclude that although the lag may vary with time, such variation is
marginal and there is little advantage in using a satellite-specific or other time-varying lag in double-difference processing.
We filter the GPS data either by stacking a number of days of processed coordinate residuals using the optimum “sidereal”
lag (23 h 55 m 54 s), and removing these stacked residuals from the day in question (coordinate space), or by a similar method
using double-difference carrier-phase residuals (observational space). Either method results in more consistent and homogeneous
set of coordinates throughout the dataset compared with unfiltered processing. Coordinate stacking reduces geometry-related
repeating errors (mainly multipath) better than carrier-phase residual stacking, although the latter takes less processing
time to achieve final filtered coordinates. Thus, the optimal stacking method will depend on whether coordinate precision
or computational time is the over-riding criterion. 相似文献
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在GPS约束平差中,地面已知点的粗差或错误会导致GPS网形扭曲变形,给平差结果带来失真。当平差结果不能通过可靠性检验时,如何确定含有粗差的点以及估计粗差的大小显得很重要。在论证WGS一84地心平面坐标差与国家(如北京54坐标)或地方参心平面坐标差的一致性基础上,通过分析两种坐标对应点的差值及其比值确定粗差点。 相似文献
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Lambert Wanninger 《Journal of Geodesy》1995,69(4):283-291
Distance-dependent errors due to ionospheric refraction complicate ambiguity resolution and limit the accuracy attainable in GPS baseline determination. This paper presents an approach for modelling these errors from the observations of several permanent GPS-stations surrounding the area of interest. Regional ionospheric correction models are produced epoch-by-epoch and satellite-by-satellite. It is shown that after their application, observation residuals, fractional parts of estimated ambiguities, and single-frequency coordinate errors are greatly reduced, thus improving ambiguity resolution even under disturbed ionospheric conditions, with short observation sessions, in the case of baseline lengths of more than 10 km, and with singlefrequency and dual-frequency data. 相似文献
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GPS形变监测网基线处理中系统误差的分析 总被引:18,自引:3,他引:18
分析了高精度GPS形变监测网基线处理中系统误差产生的原因,分类及其对基线处理的影响,并在此基础上提出消除和削弱这些系统误差影响的一些原则和算法。 相似文献