Journal of Geodesy最新文献_第2页

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IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-05-10 DOI: 10.1007/s00190-025-01966-2

Gyula Tóth

引用次数: 0

Three-dimensional tomographic reconstruction of ionospheric sporadic E layers with constraints from GNSS radio occultation data GNSS射电掩星数据约束下电离层散射E层三维层析重建

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-05-05 DOI: 10.1007/s00190-025-01962-6

Tianyang Hu, Xiaohua Xu, Jia Luo, Haifeng Liu

{"title":"Three-dimensional tomographic reconstruction of ionospheric sporadic E layers with constraints from GNSS radio occultation data","authors":"Tianyang Hu, Xiaohua Xu, Jia Luo, Haifeng Liu","doi":"10.1007/s00190-025-01962-6","DOIUrl":"https://doi.org/10.1007/s00190-025-01962-6","url":null,"abstract":"Ionospheric sporadic E (Es) layers are thin layers with enhanced ionospheric electron densities (IEDs) which occur frequently in ionospheric E region. Previous detecting method based on ground-based global navigation satellite system (GNSS) observations can only obtain the horizontal maps rather than the vertical distributions and structures of Es layers. This study proposes a computerized ionospheric tomography (CIT) method with constraints from GNSS radio occultation data for the reconstruction of three-dimensional (3-D) structure and evolution of Es layers. The strong Es layers that occurred in Australia on January 11, 2021, and in North America on August 4, 2021, are chosen for reconstruction, and the COSMIC-2 IED profiles in the reconstruction region and its surrounding area are used as constraints in the CIT process. The IED distribution in F region is reconstructed at first by using only slant total electron content (STEC) without significant sudden disturbances, and then the E region contribution to STEC is estimated by subtracting the F region contribution, based on which the 3-D structures of Es layers with high spatial and temporal resolutions are reconstructed consequently. The reconstructed results in F and E regions are assessed separately, which show good consistence with GNSS STEC, global ionospheric maps, or ionosonde observations. The evolution of Es layer structures in the reconstructed region is further analyzed, and the large-scale Es structure spanning over more than 10° in longitude and the movement of Es patches are clearly revealed. Particularly, the reconstruction results successfully trace the vertical variation in the altitudes of Es layers.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"56 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143910478","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

Aligning GPS/Galileo/BDS satellite integer clock products across day boundaries for continuous time and frequency transfer 校准GPS/Galileo/BDS卫星整数时钟产品，实现连续时间和频率传输

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-05-04 DOI: 10.1007/s00190-025-01955-5

Jihang Lin, Jianghui Geng, Qiyuan Zhang

{"title":"Aligning GPS/Galileo/BDS satellite integer clock products across day boundaries for continuous time and frequency transfer","authors":"Jihang Lin, Jianghui Geng, Qiyuan Zhang","doi":"10.1007/s00190-025-01955-5","DOIUrl":"https://doi.org/10.1007/s00190-025-01955-5","url":null,"abstract":"GNSS integer ambiguity precision point positioning (IPPP) with satellite integer clock products is currently one of the most precise techniques for time and frequency transfer. However, a challenging issue that hampered the long-term performance of IPPP is the day-boundary discontinuity (DBD) that manifests at UTC (Coordinated Universal Time) midnights during the processing of multi-day GNSS observations. Users’ remedy to eliminate such receiver clock DBDs is to identify the integer offset of ambiguities across days, but residual DBDs could still potentially exceed 100 ps. In this study, we propose an alternative but more efficient approach to eliminate the DBDs of satellite orbit/clock/bias products as an integral, while users would directly achieve receiver clocks without DBDs rather than being troubled to fix them through carrier-phase ambiguity connection. Such a post-processing alignment approach is applicable to IGS satellite integer products processed in daily batches and does not rely on the respective smoothness of orbits or clocks. After application to the rapid multi-GNSS Experiment (MGEX) product at Wuhan University, the residual discontinuities of satellite integer clocks for each GPS/Galileo/BDS-3 satellite typically do not exceed 0.05 cycles of narrow-lane wavelengths. In continuous time and frequency transfer over a 31-day period, DBDs in all nine IPPP time links are smaller than 25 ps with a standard deviation of 10 ps, compared to 60–90 ps for the legacy strategy and unaligned products. This day-boundary alignment approach is suitable for common satellite integer products in the International GNSS Service (IGS) and has been routinely implemented in Wuhan University’s rapid MGEX satellite orbit/clock/bias products since January 1, 2023.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"53 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903119","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

Accurate computation of gravitational curvature of a tesseroid 曲面重力曲率的精确计算

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-04-29 DOI: 10.1007/s00190-025-01958-2

Xiao-Le Deng

{"title":"Accurate computation of gravitational curvature of a tesseroid","authors":"Xiao-Le Deng","doi":"10.1007/s00190-025-01958-2","DOIUrl":"https://doi.org/10.1007/s00190-025-01958-2","url":null,"abstract":"In recent years, the fundamental quantity of the gravitational field has been extended from gravitational potential, gravitational vector, and gravitational gradient tensor to gravitational curvature with its first measurement along the vertical direction in laboratory conditions. Previous studies numerically identified the near-zone and polar-region problems for gravitational curvature of a tesseroid, but these issues remain unresolved. In this contribution, we derive the new third-order central and single-sided difference formulas with one, two, and three arguments using the finite difference method. To solve these near-zone and polar-region problems, we apply a numerical approach combining the conditional split, finite difference, and double exponential rule based on these newly derived third-order difference formulas when the computation point is located below, inside, and outside the tesseroid. Numerical experiments with a spherical shell discretized into tesseroids reveal that the accuracy of gravitational curvature is about 4–8 digits in double precision. Numerical results confirm that when the computation point moves to the surface of the tesseroid, the relative and absolute errors of gravitational curvature do not change much, i.e., the near-zone problem can be adequately solved using the numerical approach in this study. When the latitude of the computation point increases, the relative and absolute errors of gravitational curvature do not increase, which solves the polar-region problem with this stable numerical approach. The provided Fortran codes at https://github.com/xiaoledeng/xtessgc-xqtessgc will help with potential applications for the gravitational field of different celestial bodies in geodesy, geophysics, and planetary sciences.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"19 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889526","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

3D high-resolution numerical modelling of altimetry-derived marine gravity data 海洋重力测高数据的三维高分辨率数值模拟

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-04-26 DOI: 10.1007/s00190-025-01957-3

Róbert Čunderlík, Marek Macák, Michal Kollár, Zuzana Minarechová, Karol Mikula

{"title":"3D high-resolution numerical modelling of altimetry-derived marine gravity data","authors":"Róbert Čunderlík, Marek Macák, Michal Kollár, Zuzana Minarechová, Karol Mikula","doi":"10.1007/s00190-025-01957-3","DOIUrl":"https://doi.org/10.1007/s00190-025-01957-3","url":null,"abstract":"The paper presents 3D numerical modelling of the altimetry-derived marine gravity data with the high horizontal resolution 1 × 1 arc min. The finite volume method (FVM) as a numerical method is used to solve the altimetry–gravimetry boundary-value problem. Large-scale parallel computations result in the disturbing potential in every finite volume of the discretized 3D computational domain between an ellipsoidal approximation of the Earth’s surface and an upper boundary chosen at altitude of 200 km. Afterwards, the first, second or higher derivatives of the disturbing potential in different directions can be numerically derived using the finite differences. A crucial impact on achieved accuracy has the process of preparing the Dirichlet boundary conditions over oceans/seas. It is based on nonlinear filtering of the geopotential generated on a mean sea surface (MSS) from a GRACE/GOCE-based satellite-only global geopotential model. The paper presents different types of the altimetry-derived marine gravity data obtained on the DTU21_MSS as well as at higher altitudes of the 3D computational domain. The altimetry-derived gravity disturbances on the DTU21_MSS are compared with those from recent datasets like DTU21_GRAV or SS_v31.1. Standard deviations of the residuals are about 2.7 and 2.9 mGal, respectively. The obtained altimetry-derived gravity disturbances at higher altitudes are compared with airborne gravity data from the GRAV-D campaign in US showing accuracy about 3 mGal. In addition, the gravity disturbing gradients as the second derivatives or the third derivatives are provided with the same high resolution on the DTU21_MSS as well as at different altitudes.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"4 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875898","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

Numerical modeling and analysis of GNSS carrier-phase diffraction error in occlusion environments 遮挡环境下GNSS载波相位衍射误差的数值模拟与分析

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-04-25 DOI: 10.1007/s00190-025-01956-4

Ruijie Xi, Luming Han, Qusen Chen, Weiping Jiang, Xiaolin Meng, Xiangdong An, Wei Xuan

{"title":"Numerical modeling and analysis of GNSS carrier-phase diffraction error in occlusion environments","authors":"Ruijie Xi, Luming Han, Qusen Chen, Weiping Jiang, Xiaolin Meng, Xiangdong An, Wei Xuan","doi":"10.1007/s00190-025-01956-4","DOIUrl":"https://doi.org/10.1007/s00190-025-01956-4","url":null,"abstract":"In urban canyons or natural valleys, diffraction effect occurs when the signal of Global Navigation Satellite Systems (GNSS) transmits to the edge of obstructions, such as buildings, trees, and slopes, resulting in large diffraction error, which is one of the important error sources in carrier-phase-based precise positioning. However, the theoretical formula derivation and numerical modeling of the diffraction error have been rarely studied. In this study, we derived the theoretical formula of the diffraction error based on the geometrical structure of the signal propagation path in satellite-obstruction-antenna geometry. Then, the diffraction error extraction and modeling method were proposed to study the time-varying characteristics of diffraction error and verify the validity of the theoretical formula of the diffraction error. Based on the GNSS data collected in occlusion environment, a designed experiment was carried out. The results show that the diffraction error generally increases or decreases monotonically, and mostly the amplitude of it could be larger than 50 mm and even reach 200 mm. The time-varying characteristics of diffraction error can be precisely simulated with the vertical and horizontal diffraction formulas developed, and the diffraction error model established could be applied in sidereal filtering method to correct the diffraction error. From the experiment, the fixed rate of ambiguity resolution can be improved from 76.8 to 98.87%, and the positioning reliability is improved from 80 to over 98% with the diffraction correction. The results of this paper provided theoretical basis and experience for the processing of GNSS diffraction error and show the significance in applications of high-precision positioning.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"3 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875897","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

Spectral gravity forward modelling of 3D variable densities using an arbitrary integration radius with application to lunar topographic masses 基于任意积分半径的三维变密度光谱重力正演模拟及其在月球地形质量中的应用

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-04-23 DOI: 10.1007/s00190-025-01951-9

Blažej Bucha

{"title":"Spectral gravity forward modelling of 3D variable densities using an arbitrary integration radius with application to lunar topographic masses","authors":"Blažej Bucha","doi":"10.1007/s00190-025-01951-9","DOIUrl":"https://doi.org/10.1007/s00190-025-01951-9","url":null,"abstract":"Spectral gravity forward modelling delivers gravitational fields of mass distributions by evaluating Newton’s integral in the spectral domain. We generalize its spherical harmonic variant to 3D variable densities and to any integration radius. The former is achieved by expressing the density function as an infinite-degree polynomial in the radial direction with polynomial coefficients varying laterally as a bounded function. The latter generalization builds on Molodensky’s truncation coefficients and allows to evaluate gravitational contribution of masses found up to and beyond some integration radius. In a numerical study, we forward-model lunar topographic masses by first assuming constant and then 3D variable density. Our validation with respect to GRAIL-based models shows that the 3D density model yields superior gravitational field compared to the constant density model. Thanks to the efficiency of FFT-based spherical harmonic transforms, the new technique can be employed in high-resolution modelling of topographic potentials. A numerical implementation is made available through CHarm, which is a C/Python library for high-degree spherical harmonic transforms accessible at https://github.com/blazej-bucha/charm.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"42 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866929","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 new method for determining geoid gradient components from SWOT wide-swath data for marine gravity field 利用海洋重力场SWOT宽幅数据确定大地水准面梯度分量的新方法

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-04-12 DOI: 10.1007/s00190-025-01950-w

Daocheng Yu, Xiaoli Deng, Ole Baltazar Andersen, Huizhong Zhu, Jia Luo

{"title":"A new method for determining geoid gradient components from SWOT wide-swath data for marine gravity field","authors":"Daocheng Yu, Xiaoli Deng, Ole Baltazar Andersen, Huizhong Zhu, Jia Luo","doi":"10.1007/s00190-025-01950-w","DOIUrl":"https://doi.org/10.1007/s00190-025-01950-w","url":null,"abstract":"The Surface Water and Ocean Topography (SWOT) altimeter mission provides a significant opportunity to improve the accuracy of geoid gradients (GGs) and marine gravity fields. This paper presents a new method, namely LSA3, to determine the north and east ((xi ) and (eta )) components of GGs from simulated and real SWOT data in the northern South China Sea. To fully use SWOT’s fine-scale sea surface height (SSH) measurements, LSA3 first determines GGs in SWOT along-, cross- and oblique-track directions and constructs a grid for each gradient. Least-squares adjustment (LSA), accounting for correlations of the GGs in three directions, is then employed to point-wisely estimate (xi ) and (eta ) components at grid points. The accuracy of estimated (xi ) and (eta ) components is assessed using those computed by numerical differentiations. For comparison, GG components are also estimated using least-squares collocation (LSC) and weighted LSA (WLSA) methods with empirically determined data window sizes and without accounting for correlations. Simulated results show that LSA3-estimated GG components achieve the root-mean-square deviation (RMSD) values of 0.43 and 0.47 microrad for (xi ) and (eta ), respectively, outperforming LSC (0.82 and 0.86 microrad) and WLSA (0.49 and 0.54 microrad). The results from the real SWOT data indicate that LSA3 is comparable to LSC with a mean RMSD of 1.88 mgal for marine gravity anomalies when compared to shipborne gravity data, but LSA3 is more computationally efficient than LSC. Compared to the Sandwell V32.1 gravity field, SWOT improves gravity accuracy by an average of 12.0%, with a maximum improvement of 44.3% for a single ship trajectory.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"43 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822915","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

Theory for the ambiguity function method: probability model and global solution 模糊函数方法的理论：概率模型和全局解

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-04-04 DOI: 10.1007/s00190-025-01945-7

P. J. G. Teunissen, L. Massarweh

引用次数: 0

Depth modernization by integrating mean sea surface model, ocean tide model, and precise ship positioning 通过综合平均海面模型、海潮模型和精确船舶定位实现深度现代化

IF 4.4 2区地球科学

Journal of Geodesy Pub Date : 2025-03-24 DOI: 10.1007/s00190-025-01949-3

Cheinway Hwang, Chung-Yen Kuo, Hsuan-Chang Shih, Wen-Hsuan Huang, Wen-Hau Lan

{"title":"Depth modernization by integrating mean sea surface model, ocean tide model, and precise ship positioning","authors":"Cheinway Hwang, Chung-Yen Kuo, Hsuan-Chang Shih, Wen-Hsuan Huang, Wen-Hau Lan","doi":"10.1007/s00190-025-01949-3","DOIUrl":"https://doi.org/10.1007/s00190-025-01949-3","url":null,"abstract":"This paper presents a study on depth modernization, paralleling height modernization for land elevations. Depth modernization integrates mean sea surface (MSS) models, ocean tide models, and precise ship positioning to achieve accurate seafloor depth measurements. Conventional methods rely on tidal corrections and chart datum from temporary tide gauges, which can be challenging in regions with complex tidal patterns and inconsistent chart datums. For depth modernization, we developed (1) a hybrid MSS model using satellite altimeter data, tide gauge records, and a regional geoid model, and (2) a hydrodynamic-driven ocean model with 26 tidal constituents to determine separations between the hybrid MSS and five tidal surfaces, resulting in five ellipsoid-based surfaces analogous to a geoid model for height modernization. Precise ship positioning is demonstrated using GNSS data collected by the Legend research ship in the Pacific Ocean east of Taiwan and the Canadian spatial reference system precise point positioning toolbox. We used measurements in the Taiwan Strait to show how modern depth is implemented. Comparisons of depths in four regions from the conventional and modern methods show small (a few cm) to moderate (a few dm) differences with some variability depending on the region and equipment. Discontinuities in depths from the conventional method are analyzed. Depth modernization has significantly benefited rapid and accurate bathymetric mapping for electronic navigation charts. Future work in MSS and ocean tide models and the availability of PPP tools for depth modernization are discussed. For mapping agencies worldwide, depth modernization should be prioritized alongside height modernization to ensure rapid and accurate depth data provision.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"2 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678150","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