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Multipath disturbance is one of the most important error sources in high-accuracy global positioning system (GPS) positioning and navigation. A new data filtering method, based on the Vondrak filter and the technique of cross-validation, is developed for separating signals from noise in data series, and applied to mitigate GPS multipath effects in applications such as deformation monitoring. Both simulated data series and real GPS observations are used to test the proposed method. It is shown that the method can be used to successfully separate signals from noise at different noise levels, and for varying signal frequencies as long as the noise level is lower than the magnitude of the signals. A multipath model can be derived, based on the current-day GPS observations, with the proposed method and used to remove multipath errors in subsequent days of GPS observations when taking advantage of the sidereal day-to-day repeating characteristics of GPS multipath signals. Tests have shown that the reduction in the root mean square (RMS) values of the GPS errors ranges from 20% to 40% when the method is applied. 相似文献
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Adaptive wavelet transform based on cross-validation method and its application to GPS multipath mitigation 总被引:3,自引:2,他引:1
Global positioning system (GPS) multipath disturbance is a bottleneck problem that limits the accuracy of precise GPS positioning
applications. A method based on the technique of cross-validation for automatically identifying wavelet signal layers is developed
and used for separating noise from signals in data series, and applied to mitigate GPS multipath effects. Experiments with
both simulated data series and real GPS observations show that the method is a powerful signal decomposer, which can successfully
separate noise from signals as long as the noise level is lower than about half of the magnitude of the signals. A multipath
correction model is derived based on the proposed method and the sidereal day-to-day repeating property of GPS multipath signals
to remove multipath effects on GPS observations and to improve the quality of the GPS measurements. 相似文献
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一种基于交叉证认技术的自适应小波变换及其在削减GPS多路径误差中的应用 总被引:2,自引:1,他引:1
多路径效应影响是目前限制GPS定位精度进一步提高的瓶颈。提出用交叉证认技术自动识别小波分解的信号层,再通过小波重构实现降噪和信号提取,并将该方法应用于GPS多路径误差的削减中。对模拟数据和实际GPS观测资料的分析表明,该方法能合理分离不同噪声水平下资料序列中的信号和噪声;当噪声水平小于信号振幅的一半时,能成功分离资料序列中的高频信号。同时,运用该方法得到的多路径改正模型和GPS多路径效应的重复性,可有效地削弱多路径效应的影响,提高GPS定位精度。 相似文献
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时荣 《测绘与空间地理信息》2015,(8):175-177
多路径误差分析是北斗卫星导航系统性能评估的一项重要内容。本文给出了一种新的计算3频多路径误差的方法,该方法只需对B1和B2载波相位观测值进行处理就能得到3个频率的伪距多路径误差。利用MGEX跟踪站的数据计算了BDS的多路径误差,从GPS和BDS多路径误差比较以及纬度、轨道和频率因素分析了BDS多路径误差的特性,结果表明,BDS多路径误差小于0.5 m,符合质量检查要求,其性能优于GPS卫星系统。 相似文献
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A new method to mitigate multipath error in single-frequency GPS receiver with wavelet transform 总被引:2,自引:1,他引:1
One of the major errors in high-precision GPS positioning is multipath. Multipath effect modeling and reduction have been a challenging issue in high-accuracy GPS positioning applications due to its special properties. Different methods have been employed to mitigate this error including hardware and software approaches. We reduce C/A code multipath error by adopting an efficient software method which uses wavelet transform as a basic data processing trend. The key idea of the proposed method is using stationary wavelet transform (SWT) in GPS signal data processing. Since we have used SWT, there is complete access to high-frequency and low-frequency terms in both time and frequency domains, and we can apply appropriated procedures to mitigate this error. The multipath error mostly is a low-frequency term. In our proposed method, the double difference (DD) residuals are applied to the SWT to identify the multipath disturbance. The extracted multipath is then used to correct DD observations. Our experiments include three data sets to investigate the proposed method and compare it with existing algorithms. We used simulations for two of these data sets. The results indicate the efficiency of the proposed method over existing algorithms. 相似文献
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HUANG Shengxiang JIN Xiangsheng YANG Baocen 《地球空间信息科学学报》2006,9(2):79-83
IntroductionThere are many factors that affect the precisionand reliability of GPS measuring. Generally, theerror sources can be grouped into the followingthree classes: errors correlated with the satellites(such as ephemeris error, satellite clock error,… 相似文献
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GPS残差信号提取的时间序列分析方法 总被引:1,自引:0,他引:1
作者使用零基线单差模型研究并讨论了GPS量测噪声的时相关特性,并得出了GPS观测噪声具有类似白噪声或一阶高斯马尔科夫噪声的特殊性质。利用观测噪声所具备的这种特殊性质,作者首先尝试了从时间域的角度分离和提取了残差序列中的多路径信号特性,成功验证了多路径信号在连续两个恒星日内会有所重复的结论。作者提出了一种使用时相关分析法检测观测序列中周期信号(如冰期反弹、固体潮、极潮等)的设想并就其可行性进行了分析研究。最后,针对观测噪声的这种特殊性质,探讨了结合使用小波分析法提取GPS沉降监测信号的可行性。 相似文献
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GPS动态监测中多路径效应的规律性研究 总被引:14,自引:1,他引:14
在分析GPS多路径效应特性的基础上,结合GPS动态变形监测的特点,对连续多天的观测数据解算结果采用滤波与周日位置求差相结合的方法进行数据处理。研究结果表明,多路径误差具有较强的周日重复性,在有效地削弱多路径效应的影响后,GPS动态监测的三维位置精度可以达到mm级,尤其是垂直方向的精度改善明显。 相似文献
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随机误差和多径效应作为GPS变形监测中的主要误差源,严重影响着GPS测量精度。针对这一问题,本文将主成分分析(Principal Component Analysis,PCA)模型引入GPS变形监测领域,首先利用传统PCA方法将测量数据转换至特征空间,通过剔除小特征值对应的特征向量实现对高斯分布随机噪声的抑制,然后将多径噪声作为色噪声进行分析,提出一种广义PCA方法利用多径噪声的时间相关性对其进行滤除,基于实际工程测试数据的实验结果表明,相对于传统的小波噪声抑制方法,所提方法可以获得更好的噪声抑制性能。 相似文献
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Sidereal filtering based on single differences for mitigating GPS multipath effects on short baselines 总被引:5,自引:2,他引:3
Ping Zhong Xiaoli Ding Linguo Yuan Youlin Xu Kenny Kwok Yongqi Chen 《Journal of Geodesy》2010,84(2):145-158
Carrier-phase multipath effects are one of the most significant error sources in precise Global Positioning System (GPS) positioning
applications. A new sidereal filtering algorithm based on single differences is developed to mitigate multipath effects for
short-baseline high-rate GPS applications such as structural deformation monitoring. This method differs from traditional
sidereal filtering in that our method operates on the single differences rather than the coordinates or double differences.
A multipath model for the single differences on the reference day is established for each satellite and is used to remove
multipath errors from observations of subsequent days by taking advantage of the sidereal repeatability of multipath signals.
Using both simulated and real GPS observations, we demonstrate that this method is insensitive to different weighting strategies
used in computing single differences from double differences. Applying the proposed method can reduce the root mean square
(RMS) of positioning noises by 82% on average. Compared to sidereal filtering (in either coordinate or double differences
domain) and aspect repeat time adjustment, this method can further reduce the RMS values by 13 and 7%, respectively. Wavelet
spectra have shown that the proposed method is more effective in mitigating multipath errors of both long and short periods.
This method is also more advantageous in that it is applicable when different GPS satellites are observed on different days. 相似文献
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通过载噪比(CNR)、数据完整率、伪距与载波相位观测值噪声和伪距多路径效应四个指标对北斗三号卫星导航系统(BDS-3)新频点B1C/B2a车载动态数据的特性进行了分析,测试了BDS-3新频点动态精密单点定位(PPP)的性能,并与其它全球卫星导航系统(GNSS)进行了对比.试验结果表明,BDS-3新频点B2a平均CNR优于北斗卫星导航系统(BDS)其它频率,但略差于GPS L5;相较于其它GNSS,BDS数据完整率相对较高,其中BDS-3 B2a新频点数据完整率最高;BDS-3 B2b伪距观测值噪声最小,B1C和B2a伪距观测值噪声约为B2b信号的3倍,但不同频率相位观测值噪声处于同一量级;对于伪距多路径而言,BDS-3 B1C/B2a信号略小于B2b信号.总体而言,GPS L5信号抑制多路径效应的能力最强.在动态PPP性能方面,BDS-3 B1C/B2a双频组合动态PPP定位精度最优,其三维(3D)均方根(RMS)误差为0.439 m,相比BDS B1I/B3I、GPS L1/L2、 GLONASS G1/G2和Galileo E1/E5a双频组合PPP,其精度改善率分别为49%、 5... 相似文献
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对搭载美国BlackJack接收机的CHAMP/GRACE-A/Jason-2卫星和搭载国产接收机的HY2A/ZY3/TH1卫星的星载GPS数据的伪距多路径误差与观测噪声进行了研究,重点分析了国产接收机伪距多路径误差的变化特性,并研究了多路径误差与观测噪声对星载GPS自主定轨的影响。结果表明:国产接收机的C/A码与P1码伪距观测精度要整体差于美国的BlackJack接收机,而P2码伪距观测精度要整体优于BlackJack接收机;国产接收机P1码伪距受多路径效应影响较大,其多路径误差随高度角减小存在单调递增的变化趋势,其中HY2A、ZY3与TH1卫星的多路径误差最大分别可达3.6 m、1.8 m与0.7 m;这种单调递增变化的多路径误差会导致星载GPS自主定轨位置结果在径向与切向产生系统性偏差。 相似文献
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Evolution of Multipath Error Reduction with Signal Processing 总被引:1,自引:0,他引:1
GPS Solutions - The described method of code and carrier multipath error reduction is a refinement of the strobe method of pseudo random noise (PRN) signal processing. This method utilizes as a... 相似文献
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Multipath is one of the most important error sources in Global Navigation Satellite System (GNSS) carrier-phase-based precise
relative positioning. Its theoretical maximum is a quarter of the carrier wavelength (about 4.8 cm for the Global Positioning
System (GPS) L1 carrier) and, although it rarely reaches this size, it must clearly be mitigated if millimetre-accuracy positioning
is to be achieved. In most static applications, this may be accomplished by averaging over a sufficiently long period of observation,
but in kinematic applications, a modelling approach must be used. This paper is concerned with one such approach: the use
of ray-tracing to reconstruct the error and therefore remove it. In order to apply such an approach, it is necessary to have
a detailed understanding of the signal transmitted from the satellite, the reflection process, the antenna characteristics
and the way that the reflected and direct signal are processed within the receiver. This paper reviews all of these and introduces
a formal ray-tracing method for multipath estimation based on precise knowledge of the satellite–reflector–antenna geometry
and of the reflector material and antenna characteristics. It is validated experimentally using GPS signals reflected from
metal, water and a brick building, and is shown to be able to model most of the main multipath characteristics. The method
will have important practical applications for correcting for multipath in well-constrained environments (such as at base
stations for local area GPS networks, at International GNSS Service (IGS) reference stations, and on spacecraft), and it can
be used to simulate realistic multipath errors for various performance analyses in high-precision positioning. 相似文献
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提出了一种基于增广参数Kalman滤波的多路径效应系统误差估计方法,将系统误差作为状态参数,并对其建立一阶AR模型,同时利用多路径重复性特性,更新多路径误差改正模型,在一定程度上解决了固定多路径误差模型随着时间推移重复性减小而有效性降低的问题,并利用16d实测数据例证了本方法具有一定的可行性和有效性。 相似文献
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利用交叉证认的方法,提出一种新的基于EMD滤波去噪方法,并将其应用于GPS多路径效应的研究中。通过模拟实验及实测数据分析表明,该方法能够自适应地选择IMF中的信号层数,削弱随机噪声,合理地分离信号和噪声。利用该滤波方法去噪并建立具有重复性的多路径误差效应改正模型,可有效地削弱多路径效应的影响,进而提高GPS动态变形监测的精度。 相似文献