Journal of Geodesy最新文献

{"title":"IAG Newsletter","authors":"Martin Sehnal, Helmut Klima","doi":"10.1007/s00190-026-02097-y","DOIUrl":"https://doi.org/10.1007/s00190-026-02097-y","url":null,"abstract":"","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"27 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148842915","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}

{"title":"Enhancing GNSS RTK positioning in complex scenarios: an extended robust strategy integrating random forest-based NLOS probability estimation","authors":"Wei Zhan, Xiufeng He, Yijie Huang","doi":"10.1007/s00190-026-02103-3","DOIUrl":"https://doi.org/10.1007/s00190-026-02103-3","url":null,"abstract":"","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"36 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148842914","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}

{"title":"Stochastic modelling of mass variations using local terrain information","authors":"Dimitrios Tsoulis, Georgia Gavriilidou","doi":"10.1007/s00190-026-02107-z","DOIUrl":"https://doi.org/10.1007/s00190-026-02107-z","url":null,"abstract":"","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"35 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148728736","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}

{"title":"Analytical solution of tesseroid gravitational effect with linear approximation II: with different integration elements","authors":"Linshan Zhong, Xiancai Zou, Jiancheng Li","doi":"10.1007/s00190-026-02067-4","DOIUrl":"https://doi.org/10.1007/s00190-026-02067-4","url":null,"abstract":"The Newtonian volume integral is the fundamental mathematical framework for modeling the gravitational effects of mass bodies with arbitrary geometry. Tesseroids provide a natural discretization of spherical shells and are therefore well suited for global-scale applications. However, the curved geometry of tesseroids makes it difficult to derive analytical solutions for the Newtonian integral. Numerical approaches, such as Taylor expansions and Gauss–Legendre quadrature, suffer from two major limitations: near-zone errors and polar-region effects, the latter being closely related to the choice of integration elements. In this study, we derive linearly analytical solutions (LASs) for the gravitational effect of tesseroids by applying linear approximations to both the integrands and variables, based on multiple integration elements with and without the <inline-formula><alternatives><mml:math><mml:mrow><mml:mtext>cos</mml:mtext><mml:mi>φ</mml:mi><mml:mmultiscripts><mml:mrow></mml:mrow><mml:mrow></mml:mrow><mml:mo>′</mml:mo></mml:mmultiscripts></mml:mrow></mml:math><tex-math>documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$text{cos}{varphi }{^{prime }}$$end{document}</tex-math></alternatives></inline-formula> term. The main results are as follows: (1) With respect to the integration elements, the <inline-formula><alternatives><mml:math><mml:mrow><mml:mtext>cos</mml:mtext><mml:mi>φ</mml:mi><mml:mmultiscripts><mml:mrow></mml:mrow><mml:mrow></mml:mrow><mml:mo>′</mml:mo></mml:mmultiscripts></mml:mrow></mml:math><tex-math>documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$text{cos}{varphi }{^{prime }}$$end{document}</tex-math></alternatives></inline-formula> term preserves the meridian convergence effect, and both numerical and analytical methods constructed with integration elements containing this term are inherently free from polar-region errors. (2) For Newtonian integration with arbitrary-order polynomial density, numerical integration does not introduce additional errors; in particular, the error does not increase with the polynomial degree. (3) We characterize, for the first time, the radial extent of a tesseroid—defined by its latitudinal and longitudinal coordinates—as a composite function, and derive LAS for the Newtonian integral over a non-rectangular domain. This formulation enables accurate modeling of tesseroids with inclined top or bottom surfaces. Building upon previous developments of LAS in spherical polar coordinates, this study establishes a solid mathematical foundation for modeling tesseroid gravitational effects using linearly analytical expressions. It also advances the understanding of Newtonian in","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"46 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148687817","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}

{"title":"The alignment of tie vectors in the ITRF: an assessment","authors":"Pierguido Sarti, Luca Vittuari, Alessandra Borghi, Maria Alessandra Tini, Monia Negusini, Zuheir Altamimi, Jim R. Ray","doi":"10.1007/s00190-026-02104-2","DOIUrl":"https://doi.org/10.1007/s00190-026-02104-2","url":null,"abstract":"The tie vectors at co-location sites are required for combining the individual space geodetic solutions and computing the International Terrestrial Reference Frame. Their provision to the combination centres entails a proper and accurate alignment of the tie vector into the global geocentric frame. In order to assess the impact of different alignment strategies on the space geodetic combination, we test four alignment approaches—two similarity transformations and two transformations based on the local values of the deflection of the vertical—and focus on the residuals of the combination. Our results clearly show that the alignment strategy not only controls the orientation on the tie vector in the global frame—determining its global coordinates and components—but also impacts the magnitude of the tie vector’s combination residuals to an extent that can exceed the 1 cm level. In practice, the information carried by the <italic>same</italic> tie vector is affected by the alignment strategy—a step in the tie vectors’ production that we prove is critical and that can impact the combination of space geodetic techniques. At both sites, the alignment strategy (local topocentric to the global geocentric ITRF frame) that ensures higher consistency (i.e. smaller residuals) in the computation is the similarity transformation that makes use of all the available space geodetic reference points and no information about the DoV.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"35 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716509","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}

{"title":"Toward a GNSS network solution in space based on double-differences between LEO satellites","authors":"Lukas Müller, Markus Rothacher, Benedikt Soja, Daniel Arnold, Adrian Jäggi","doi":"10.1007/s00190-026-02059-4","DOIUrl":"https://doi.org/10.1007/s00190-026-02059-4","url":null,"abstract":"As low-Earth orbit (LEO) satellites are increasingly equipped with highly precise Global Navigation Satellite Systems (GNSS) receivers, new opportunities for GNSS-based precise orbit determination (POD) arise. The availability of GNSS observations from satellites that are geometrically well distributed over the entire Earth may enable the formation of an independent GNSS network in LEO, which can be processed solely on the basis of double-difference (DD) observations. This study presents a first attempt to compute a network solution of GNSS DD observations in space that combines data from eight satellites, including GRACE-FO C/D, Sentinel-3A/B, Sentinel-6A and Swarm A/B/C. Using satellite laser ranging (SLR) validation, we show that the absolute position accuracy of an ambiguity-float network solution increases from about 4 cm 1D RMS in a constellation of three satellites to about 2 cm–2.5 cm in a constellation of eight satellites. Similar results are obtained by comparing the baseline lengths from our DD network solution with those derived from external ambiguity-fixed zero-difference (ZD) orbits, with differences at a level of 2 cm to 3 cm RMS for a network of eight satellites. For both the SLR residuals and the baseline consistency, an improvement of up to 0.5 cm can be achieved when resolving 60 % to 70 % of the carrier-phase ambiguities of highly dynamic baselines to integer values. Overall, the geometric distribution of the satellites and high dynamics of the constellation prove to be beneficial for computing a DD network solution in space. This is particularly promising in the view of large LEO constellations currently being developed, with a much higher number of spacecraft and a uniform global coverage, where the advantages of the network approach presented in this study will become even more significant.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"26 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148687851","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}

{"title":"Characterizing the systematic bias of tropospheric refraction asymmetry in spaceborne and airborne grazing GNSS-R altimetry","authors":"Minfeng Song, Xiufeng He, Milad Asgarimehr, Xiaolei Wang, Jens Wickert","doi":"10.1007/s00190-026-02099-w","DOIUrl":"https://doi.org/10.1007/s00190-026-02099-w","url":null,"abstract":"Grazing Global Navigation Satellite System Reflectometry (GNSS-R) altimetry, while promising for precise surface height retrieval, faces challenges from tropospheric refraction. Beyond path delay errors, tropospheric refraction can cause an asymmetry in the incident and reflected signal paths due to tropospheric gradients and the asymmetric observation geometry. The impact of this refraction asymmetry on grazing GNSS-R altimetry remains unclear. This study systematically quantifies this impact and characterizes the resulting errors in grazing observations. We propose a new surface height retrieval model that accounts for refraction asymmetry and applies to both spaceborne and airborne scenarios. Through a 30-day global GNSS-R simulation, in conjunction with European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data and a ray tracing technique, our results show that decimeter-level systematic bistatic delay biases can be observed in airborne scenarios (3.5 km), increasing exponentially with decreasing elevation angles. In contrast, these errors are millimeter-level in spaceborne scenarios (530 km). A comparison with the traditional height retrieval model reveals that uncorrected refraction asymmetry in airborne observations can introduce decimeter- to meter-level altimetric errors at extremely low elevation angles (2–7 degrees). This finding highlights the critical importance of accounting for the effects of refraction asymmetry on airborne grazing GNSS-R altimetry, especially for continuous coherent observations covering a wide range of low elevation angles.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"194 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148687850","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}

{"title":"Toward accurate extraction of Earth’s free oscillation through a novel deep-learning-based window selection","authors":"Shiyu Zeng, Binbin Liao, Rumeng Guo, Kun Dai, Yijun Zhang, Xiaoming Cui, Jiangcun Zhou, Jianqiao Xu, Xiaodong Chen, Mingqiang Hou, Heping Sun","doi":"10.1007/s00190-026-02100-6","DOIUrl":"https://doi.org/10.1007/s00190-026-02100-6","url":null,"abstract":"The detection and analysis of the Earth’s free oscillations in the form of normal modes contribute to our understanding of the planet’s structure, dynamics, and seismicity. However, false and dismissed recognitions of the focused normal mode signals prevent the detailed exploration of the Earth’s interior due to the complex patterns of the normal mode spectrum. Here, we develop a deep-learning-based neural network, named ModeNet, which is capable of precisely and efficiently selecting the frequency windows to cover the target normal modes on noisy spectra. ModeNet achieves a remarkable precision rate in the discrimination between normal modes and noises of 98.1%, with very few false positives (normal modes misidentified as noises) and false negatives (noises misidentified as normal modes). ModeNet achieves good generalization in processing seismograms with different noise levels, components, and time windows, as well as superconducting-gravimeter (SG) observations. Extracting the frequencies of normal modes within windows selected by ModeNet and further performing a radial (1D) Earth structure inversion, our preferred model shows a better fit to the observed eigenfrequencies than the Preliminary Reference Earth Model (PREM). Therefore, ModeNet would be implemented as a potentially valuable tool for the future 3D structure inversion of the deep Earth and extraterrestrial planets.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"65 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148687849","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}

{"title":"Total effect of the geopotential on the Earth tide-generating potential","authors":"Sergey Kudryavtsev","doi":"10.1007/s00190-026-02064-7","DOIUrl":"https://doi.org/10.1007/s00190-026-02064-7","url":null,"abstract":"We aim to evaluate the effect of geopotential coefficients of high degree and order on the Earth tide-generating potential (TGP), not considered before. First, general expressions are derived for calculating the TGP caused by a joint action of the external bodies’ gravity and an <italic>arbitrary</italic> spherical harmonic in the geopotential. The obtained formulae explicitly separate the TGP coefficients, that depend on masses and positions of external bodies (the Moon, the Sun, major planets), from the coordinates of an observation point at which the TGP is evaluated. At the next step, the TGP coefficients related to the external bodies are tabulated over 30,000+ years with a small sampling step and then developed to precision harmonic series. The modern long-term ephemerides of the Moon and major planets DE441 are taken as the source. The minimum threshold for amplitudes of the harmonic series’ terms is by an order of magnitude less than that used by the previous TGP catalogues HW95 and KSM03. For the first time, the terms caused by the geopotential coefficients of the third degree in the Earth TGP development are found. The number of terms originated by the second degree harmonics in the geopotential is more than doubled. Due to using the modern planetary/lunar ephemerides, the existing terms are updated. The obtained data are released in the form of a tidal potential catalogue in two formats: KSM25 (a modified KSM03) and HW95 (a generalized version). A new type of permanent tides on the Earth’s surface is revealed. It is originated by geopotential coefficients of order 1 (mainly, c₃₁ and s₃₁) and depends on not only the latitude of the observation point, like all previously known permanent tides, but on its longitude as well.","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"61 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716514","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}

{"title":"IAG Newsletter","authors":"Martin Sehnal, Helmut Klima","doi":"10.1007/s00190-026-02071-8","DOIUrl":"https://doi.org/10.1007/s00190-026-02071-8","url":null,"abstract":"","PeriodicalId":54822,"journal":{"name":"Journal of Geodesy","volume":"64 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148682499","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}