Journal of Geodesy最新文献_第9页

5G assisted GNSS precise point positioning ambiguity resolution 5G 辅助全球导航卫星系统精确点定位模糊性解决方法

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-05-09 DOI: 10.1007/s00190-024-01850-5

Fangxin Li, Rui Tu, Pengfei Zhang, Rui Zhang, Lihong Fan, Siyao Wang, Xiaochun Lu

{"title":"5G assisted GNSS precise point positioning ambiguity resolution","authors":"Fangxin Li, Rui Tu, Pengfei Zhang, Rui Zhang, Lihong Fan, Siyao Wang, Xiaochun Lu","doi":"10.1007/s00190-024-01850-5","DOIUrl":"https://doi.org/10.1007/s00190-024-01850-5","url":null,"abstract":"This study proposes a model using 5G time-of-arrival data to assist global navigation satellite system precise point positioning ambiguity resolution. Specifically, the model addresses the problem of PPP requiring a long convergence time in partially satellite-occluded GNSS environments, such as urban canyons. First, we apply the ionosphere-free PPP model to estimate uncalibrated phase delays. Next, we combine real 5G data with GNSS data to determine whether introducing 5G observations will decrease the convergence time of the PPP solution. Experimental results reveal that the 5G-assisted PPP model can effectively improve the convergence efficiency of the float solution, lower the fixed time, and achieve greater positional reliability. Notably, the combination of GPS, BDS, and 5G with a sampling interval of 1 s obtains a fixed solution in an average of 1.12 min. Moreover, 5G-assisted GNSS positioning effectively compensates for partial satellite occlusion, optimizes the PDOP value, and speeds up ambiguity fixing. The introduction of three and more 5G base stations helps to obtain fixed solutions within 9 min when it is difficult to obtain fixed solutions relying only on GNSS. Our findings have important implications for improving the widespread applicability and effectiveness of satellite-based navigation systems in light of increasing urbanization and the rise of signal-occluding environments.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"10 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140895593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A novel method for tropospheric delay mapping function vertical modeling 对流层延迟绘图功能垂直建模新方法

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-05-09 DOI: 10.1007/s00190-024-01845-2

Junsheng Ding, Junping Chen, Jungang Wang, Yize Zhang

{"title":"A novel method for tropospheric delay mapping function vertical modeling","authors":"Junsheng Ding, Junping Chen, Jungang Wang, Yize Zhang","doi":"10.1007/s00190-024-01845-2","DOIUrl":"https://doi.org/10.1007/s00190-024-01845-2","url":null,"abstract":"In high-precision space geodetic techniques data processing, the mapping function (MF) is a key factor in mapping the radio waves from the zenith direction down to the signal incoming direction. Existing MF products, either site-wise Vienna Mapping Function (VMF1 and VMF3) or grid-wise VMF1 and VMF3, are only available at the Earth surface. For overhead areas, height correction is always required, which is becoming increasingly important with growing airborne aircraft activity. In this contribution, we introduce a novel method aimed at providing a large number of MFs to the user in a simple and efficient manner, while minimizing the loss of precision. The approach effectively represents the vertical profile of the MFs from the Earth's surface up to altitudes of 14 km. In addition, the new model corrects for height in the assessment using the fifth generation of the European Centre for Medium-Range Weather Forecasts ReAnalysis (ERA5) ray tracing calculations for a global 5° × 5° grid with 54 layers in the vertical direction, a total of 8 azimuths in the plane, and 7 elevation angles, for each day in 2021. Specifically, for both polynomial and exponential model of order 2 and 3, the relative residuals are < 0.3% for the hydrostatic delay MF coefficient (a_{{text{h}}}), and < 1% for the wet delay MF coefficient (a_{{text{w}}}). The precision of the new model on the Earth’s surface is evaluated using site-wise VMF1 and VMF3 GNSS (Global Navigation Satellite System) products from Technische Universität Wien. The root mean square error of slant hydrostatic delay and slant wet delay at a 3° elevation angle is approximately 4–5 cm and 2–5 cm, respectively.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"19 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140895630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mitigating the effect of source structure in geodetic VLBI by re-weighting observations using closure delays and baseline-to-jet orientation 利用闭合延迟和基线-喷流方向对观测结果重新加权，减轻大地测量 VLBI 中源结构的影响

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-05-09 DOI: 10.1007/s00190-024-01837-2

Niko Kareinen, Nataliya Zubko, Tuomas Savolainen, Ming Hui Xu, Markku Poutanen

{"title":"Mitigating the effect of source structure in geodetic VLBI by re-weighting observations using closure delays and baseline-to-jet orientation","authors":"Niko Kareinen, Nataliya Zubko, Tuomas Savolainen, Ming Hui Xu, Markku Poutanen","doi":"10.1007/s00190-024-01837-2","DOIUrl":"https://doi.org/10.1007/s00190-024-01837-2","url":null,"abstract":"An ideal target for geodetic very long baseline interferometry (VLBI) is a strong and point-like radio source. In reality, most celestial sources used in geodetic VLBI have spatial structure. This is as a major source of error in VLBI Global Observing System (VGOS) and also affects legacy S/X observations. Source structure causes a systematic delay, which can affect the geodetic estimates if not modelled or otherwise accounted for. In this work, we aim to mitigate its impact by extending the stochastic model used in the least-squares fitting of the VLBI group delays. We have developed a weighting scheme to re-weight the observations by parameterizing the source structure component in terms of closure delays and jet orientation relative to the observing baseline. It was implemented in the Vienna VLBI Software. To assess the performance of the extended stochastic model, we analysed the CONT17 legacy sessions and generated suitable reference solutions for comparison. The effects of re-weighting were evaluated with respect to the session fit statistics, source-wise residuals, and geodetic parameters. We find that this relatively simple noise model consistently improves the session fit by about 5% with moderate variation from session to session. The geodetic estimates are not affected to a significant level by this new weighting method. Source-wise we see improved post-fit residuals for 63 out of a total of 91 sources observed.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"20 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140903169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Improved estimates for the linear Molodensky problem 线性莫洛登斯基问题的改进估算

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-05-06 DOI: 10.1007/s00190-024-01846-1

Fernando Sansò, Barbara Betti

引用次数: 0

Anatomy of the spatiotemporally correlated noise in GNSS station position time series 剖析全球导航卫星系统台站位置时间序列中的时空相关噪声

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-04-30 DOI: 10.1007/s00190-024-01848-z

Kevin Gobron, Paul Rebischung, Kristel Chanard, Zuheir Altamimi

{"title":"Anatomy of the spatiotemporally correlated noise in GNSS station position time series","authors":"Kevin Gobron, Paul Rebischung, Kristel Chanard, Zuheir Altamimi","doi":"10.1007/s00190-024-01848-z","DOIUrl":"https://doi.org/10.1007/s00190-024-01848-z","url":null,"abstract":"Global Navigation Satellite Systems (GNSS) enable the determination of station displacements, which are essential to understanding geophysical processes and establishing terrestrial reference frames. Unfortunately, GNSS station position time series exhibit spatially and temporally correlated noise, hindering their contribution to geophysical and geodetic applications. While temporal correlations are commonly accounted for, a strategy for modeling spatial correlations is still lacking. Therefore, this study proposes a diagnosis of the spatial correlations of the white and flicker noise components of GNSS position time series, using the global Nevada Geodetic Laboratory dataset. This analysis reveals different spatial correlation patterns for white and flicker noise and the superposition of three distinct spatial correlation regimes (large-scale, short-scale and station-specific), providing insight into the noise sources. We show, in particular, that about 70% of flicker noise corresponds to large-scale variations possibly attributable to orbit modeling errors. We also evidence an increase in the spatial correlations of white noise at distances below 50 km, most pronounced in the vertical component, where 50% of the white noise appears to be driven by short-scale effects—possibly tropospheric delay mismodeling.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"58 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140817604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Combining the GPS/Galileo/BDS-3 signals on overlap frequencies for interoperable multipath hemispherical maps 在重叠频率上组合 GPS/Galileo/BDS-3 信号，绘制可互操作的多径半球地图

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-04-22 DOI: 10.1007/s00190-024-01841-6

Jianghui Geng, Pengbo Li, Guangcai Li

{"title":"Combining the GPS/Galileo/BDS-3 signals on overlap frequencies for interoperable multipath hemispherical maps","authors":"Jianghui Geng, Pengbo Li, Guangcai Li","doi":"10.1007/s00190-024-01841-6","DOIUrl":"https://doi.org/10.1007/s00190-024-01841-6","url":null,"abstract":"Multipath remains one of the major challenges in high-precision GNSS positioning. The multipath hemispherical map (MHM) based on satellites’ location repeatability in space is a popular method to mitigate GNSS multipath effects, but its performance depends on the availability of sufficient satellite orbital tracks in the skyplot. For instance, for BDS-3 medium Earth orbiters and Galileo satellites with 7-day and 10-day orbital repeat times, respectively, the skyplot of their orbital tracks will be too sparse to cover the shifting orbital tracks on the succeeding days, if only a few days of observations are used to construct MHMs. In this study, we establish an interoperable MHM using the overlap frequency signals of GPS, Galileo and BDS-3 (i.e., GPS L1/L5, Galileo E1/E5a and BDS-3 B1C/B2a). We compared the performance of GPS/Galileo/BDS-3 MHM (i.e., MP_GEC) and single-constellation MHMs (i.e., MP_G, MP_E and MP_C). The mean reduction rates of the L1/E1/B1C and L5/E5a/B2a carrier-phase residuals for the MP_GEC applied to GPS, Galileo and BDS-3 are 36% and 48%, respectively, which are 10–30% points larger compared to the MP_G, MP_E and MP_C. The MP_GEC constructed using 4 days of observations reduced the Galileo RMS positioning errors by 26%, 31% and 29% for the east, north, and up components, respectively, showing improvements of about 16, 18 and 17% points compared to the MP_E, and even approaching the RMS errors of the MP_E constructed using 10 days of observations. The results show that the interoperable GPS/Galileo/BDS-3 MHM is able to improve the spatial resolution, modeling efficiency and correction performance in mitigating multipath effects for high-precision GNSS positioning.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"1 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140637566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

GNSS ionospheric integrity monitoring based on RBF-NN: constructing single-epoch snapshot GIVD and GIVE maps 基于 RBF-NN 的全球导航卫星系统电离层完整性监测：构建单波段快照 GIVD 和 GIVE 地图

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-04-22 DOI: 10.1007/s00190-024-01838-1

Ling Yang, Yunri Fu, Jincheng Zhu, Yunzhong Shen, Chris Rizos

{"title":"GNSS ionospheric integrity monitoring based on RBF-NN: constructing single-epoch snapshot GIVD and GIVE maps","authors":"Ling Yang, Yunri Fu, Jincheng Zhu, Yunzhong Shen, Chris Rizos","doi":"10.1007/s00190-024-01838-1","DOIUrl":"https://doi.org/10.1007/s00190-024-01838-1","url":null,"abstract":"The ionosphere crucially impacts on Global Navigation Satellite System (GNSS) positioning accuracy and integrity. Recently some network-based methods have shown the potential to construct a regional/global vertical total electron content (VTEC) or grid ionospheric vertical delay (GIVD) map for accuracy augmentation purposes. However, how to use these advanced methods for integrity augmentation has not been adequately investigated. The authors have investigated a regional ionospheric integrity monitoring strategy based on the radial basis function neural network (RBF-NN), using GNSS TEC observations. Similar to the SBAS approach, the GIVD map is constructed so as to enhance positioning accuracy, and the corresponding grid ionospheric vertical error (GIVE) map is constructed for protection level calculation to enhance positioning integrity. To reduce the GIVD residuals and the GIVE values, the local ionospheric spatial activity index (LISAI) is proposed as an indicator of local ionospheric spatial activity level. The RBF-NN structure parameters are able to be adaptively determined via hierarchical clustering. Modeling results in the China region have verified that the proposed GIVD modeling method is slightly better than the classical WAAS-Kriging method. The proposed GIVE modeling method significantly outperforms WAAS-Kriging, achieving an improvement of around 46% and 25% during the ionospheric calm and active periods, respectively.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"36 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140632251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

IAG Newsletter 国际咨询组通讯

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-04-22 DOI: 10.1007/s00190-024-01840-7

Gyula Tóth

引用次数: 0

Vectorial integer bootstrapping of best integer equivariant estimation (VIB-BIE) for efficient and reliable GNSS ambiguity resolution 矢量整数引导最佳整数等差数列估计（VIB-BIE），用于高效可靠地解决全球导航卫星系统（GNSS）模糊性问题

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-04-17 DOI: 10.1007/s00190-024-01836-3

Weikai Miao, Bofeng Li, Yang Gao, Guang’e Chen

{"title":"Vectorial integer bootstrapping of best integer equivariant estimation (VIB-BIE) for efficient and reliable GNSS ambiguity resolution","authors":"Weikai Miao, Bofeng Li, Yang Gao, Guang’e Chen","doi":"10.1007/s00190-024-01836-3","DOIUrl":"https://doi.org/10.1007/s00190-024-01836-3","url":null,"abstract":"Reliable integer ambiguity resolution (IAR) is essential for carrier phase-based centimeter-level accurate positioning using global navigation satellite systems (GNSSs). In all IAR methods, the best integer equivariant (BIE) estimator is optimal in the sense of minimizing the mean-squared errors. However, the BIE estimator comprises an enumeration in the integer space of ambiguities, and its complexity grows exponentially with the number of ambiguities. Moreover, in a complex urban environment, the positioning performance of the BIE estimator is also reduced due to larger observation errors and even outliers. To address this problem, an efficient and reliable IAR method is proposed in this paper, which consists of two major steps. First, we apply the vectorial integer bootstrapping (VIB) (Teunissen et al. in J Geod 95(9):1–14, 2021) by implementing BIE in each sequential block-by-block integer estimation to improve computation efficiency, which is denoted as VIB-BIE. Second, a measure, named the acceptable probability (ACP), is defined to control the reliability of VIB-BIE estimation. Both simulated and real multi-GNSS data are employed to evaluate the performance of the proposed method and conventional BIE. The results show that the flexibility and efficiency of IAR are both improved by VIB-BIE. In a complex urban environment, the ACP-based VIB-BIE outperforms the BIE in terms of IAR reliability and positioning accuracy. Compared to the BIE, the positioning accuracies are improved by 42.4%, 34.2%, and 31.8% in the east, north, and upward directions, respectively.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"22 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140607988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Moving mountains: reevaluating the elevations of Colorado mountain summits using modern geodetic techniques 移动山脉：利用现代大地测量技术重新评估科罗拉多州山峰的海拔高度

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2024-04-15 DOI: 10.1007/s00190-024-01831-8

Kevin Ahlgren, Derek van Westrum, Brian Shaw

{"title":"Moving mountains: reevaluating the elevations of Colorado mountain summits using modern geodetic techniques","authors":"Kevin Ahlgren, Derek van Westrum, Brian Shaw","doi":"10.1007/s00190-024-01831-8","DOIUrl":"https://doi.org/10.1007/s00190-024-01831-8","url":null,"abstract":"One of the most challenging environments for accurate geoid models is in high, rugged mountain areas. Orthometric heights derived from GNSS and a geoid model can easily have errors at the decimeter level. To investigate the effect of geoid model variability on the elevations of peaks in high, rugged mountain areas, this paper is focused on the “Fourteeners” of Colorado, USA (a group of about 60 peaks that are above 14,000 feet = 4267.2 m). Airborne LiDAR data are used to determine geometric (ellipsoidal) heights, which first requires removing a hybrid geoid model, as the LiDAR data is originally provided as orthometric heights. We quantify a significant improvement when using these derived ellipsoidal heights compared with the original orthometric heights: from ± 0.074 to ± 0.054 m (RMSE), an improvement of 28%. Next, a mean geoid model is determined with a relative accuracy of ± 0.06 to 0.08 m and used as a “stand in” realization of the future, official geopotential datum of the USA, NAPGD2022. Using the LiDAR ellipsoidal heights and geoid model, elevations (and uncertainties) for each of the Fourteener summits are determined and found to be, on average, 1.6 m lower than currently published values. This is a much larger change than the 0.5 m decrease expected from the new datum shift alone. The bulk of the difference is due to the original treatments of the vertical angle, triangulation data. A reanalysis of 32 of the 60 peaks shows that the historic data were indeed too high by about 1.0 m or more. Ultimately, no peak falls below the 14,000-foot level nor are any peaks elevated above this level.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"24 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140553462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0