{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,17]],"date-time":"2026-04-17T04:36:15Z","timestamp":1776400575879,"version":"3.51.2"},"reference-count":25,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2020,2,13]],"date-time":"2020-02-13T00:00:00Z","timestamp":1581552000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41904013"],"award-info":[{"award-number":["41904013"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41601087"],"award-info":[{"award-number":["41601087"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Global Navigation Satellite System (GNSS) tomography is a popular method for measuring and modelling water vapor in the troposphere. Presently, most studies use a cuboid-shaped tomographic region in their modelling, which represents the modelling region for all measurement epochs. This region is defined by the distribution of the GNSS signals skywards from a network of ground based GNSS stations for all epochs of measurements. However, in reality at each epoch the shape of the GNSS tomographic region is more likely to be an inverted cone. Unfortunately, this fixed conic tomographic region does not properly reflect the fact that the GNSS signal changes quickly over time. Therefore a dynamic or adaptive tomographic region is better suited. In this study, a new approach that adjusts the GNSS tomographic model to adapt the size of the GNSS network is proposed, which referred to as The High Flexibility GNSS Tomography (HFGT). Test data from different numbers of the GNSS stations are used and the results from HFGT are compared against that of radiosonde data (RS) to assess the accuracy of the HFGT approach. The results showed that the new approach is feasible for different numbers of the GNSS stations when a sufficient and uniformed distribution of GNSS signals is used. This is a novel approach for GNSS tomography.<\/jats:p>","DOI":"10.3390\/rs12040617","type":"journal-article","created":{"date-parts":[[2020,2,20]],"date-time":"2020-02-20T03:20:03Z","timestamp":1582168803000},"page":"617","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["A New Approach of the Global Navigation Satellite System Tomography for Any Size of GNSS Network"],"prefix":"10.3390","volume":"12","author":[{"given":"Yuchen","family":"Wang","sequence":"first","affiliation":[{"name":"School of Geography, Geomatics and Planning, Jiangsu Normal University, Xuzhou 221116, China"},{"name":"School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8603-8322","authenticated-orcid":false,"given":"Nan","family":"Ding","sequence":"additional","affiliation":[{"name":"School of Geography, Geomatics and Planning, Jiangsu Normal University, Xuzhou 221116, China"}]},{"given":"Yu","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Geography, Geomatics and Planning, Jiangsu Normal University, Xuzhou 221116, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7763-1108","authenticated-orcid":false,"given":"Long","family":"Li","sequence":"additional","affiliation":[{"name":"School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China"},{"name":"Department of Geography, Earth System Science, Vrije Universiteit Brussel, 1050 Brussels, Belgium"}]},{"given":"Xiaoyan","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Geography, Geomatics and Planning, Jiangsu Normal University, Xuzhou 221116, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6715-0877","authenticated-orcid":false,"given":"Qingzhi","family":"Zhao","sequence":"additional","affiliation":[{"name":"College of Geomatics, Xi\u2019an University of Science and Technology, Xi\u2019an 710054, China"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zhao, Q., Yao, Y., and Yao, W. (2018). Troposphere Water Vapour Tomography: A Horizontal Parameterised Approach. Remote Sens., 10.","DOI":"10.3390\/rs10081241"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1007\/s00585-000-0223-7","article-title":"4D tropospheric tomography using GPS slant wet delays","volume":"18","author":"Flores","year":"2000","journal-title":"Ann. Geophys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"935","DOI":"10.1186\/BF03352308","article-title":"Local GPS tropospheric tomography","volume":"52","author":"Hirahara","year":"2000","journal-title":"Earth Planets Sp."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1805","DOI":"10.5194\/angeo-31-1805-2013","article-title":"GNSS troposphere tomography based on two-step reconstructions using GPS observations and COSMIC profiles","volume":"31","author":"Xia","year":"2013","journal-title":"Ann. Geophys."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"691","DOI":"10.1007\/s00190-014-0715-y","article-title":"Voxel-optimized regional water vapor tomography and comparison with radiosonde and numerical weather model","volume":"88","author":"Chen","year":"2014","journal-title":"J. Geod."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"911","DOI":"10.5194\/angeo-32-911-2014","article-title":"Near real-time water vapor tomography using ground-based GPS and meteorological data: Long-term experiment in Hong Kong","volume":"32","author":"Jiang","year":"2014","journal-title":"Ann. Geophys."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1475","DOI":"10.5194\/amt-7-1475-2014","article-title":"Limited constraint, robust Kalman filtering for GNSS troposphere tomography","volume":"7","author":"Rohm","year":"2014","journal-title":"Atmos. Meas. Tech."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"143","DOI":"10.5194\/angeo-34-143-2016","article-title":"A method to improve the utilization of GNSS observation for water vapor tomography","volume":"34","author":"Yao","year":"2016","journal-title":"Ann. Geophys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"789","DOI":"10.5194\/angeo-34-789-2016","article-title":"Optimization of GPS water vapor tomography technique with radiosonde and COSMIC historical data","volume":"34","author":"Ye","year":"2016","journal-title":"Ann. Geophys."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3511","DOI":"10.5194\/amt-11-3511-2018","article-title":"A new approach for GNSS tomography from a few GNSS stations","volume":"11","author":"Ding","year":"2018","journal-title":"Atmos. Meas. Tech."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"927","DOI":"10.1186\/BF03352307","article-title":"Three-dimensional distribution of water vapor estimated from tropospheric delay of GPS data in a mesoscale precipitation system of the Baiu front","volume":"52","author":"Seko","year":"2000","journal-title":"Earth Planets Sp."},{"key":"ref_12","unstructured":"Shrestha, S.M. (2003). Investigations into the Estimation of Tropospheric Delay and Wet Refractivity Using GPS Measurements, Department of Geomatics Engineering, University of Calgary."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"551","DOI":"10.2151\/jmsj.2004.551","article-title":"Ground-Based GPS Tomography of Water Vapor: Analysis of Simulated and Real Data","volume":"82","author":"Gradinarsky","year":"2004","journal-title":"J. Meteorol. Soc. Jpn."},{"key":"ref_14","unstructured":"Troller, M.R. (2004). GPS Based Determination of the Integrated and Spatially Distributed Water Vapor in the Troposphere. [Ph.D. Thesis, Eidgen\u00f6ssische Technische Hochschule Z\u00fcrich]."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Hoyle, V.A. (2005). Data Assimilation for 4-D Wet Refractivity Modelling in a Regional GPS Network, University of Calgary.","DOI":"10.5081\/jgps.4.1.230"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"D06303","DOI":"10.1029\/2008JD011008","article-title":"Estimates of the information provided by GPS slant data observed in Germany regarding tomographic applications","volume":"114","author":"Bender","year":"2009","journal-title":"J. Geophys. Res."},{"key":"ref_17","unstructured":"(2011). Donat Perler Water Vapor Tomography Using Global Navigation Satellite Systems, Eidgen\u00f6ssische Technische Hochschule Z\u00fcrich."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1491","DOI":"10.5194\/angeo-31-1491-2013","article-title":"GPS tomography: Validation of reconstructed 3-D humidity fields with radiosonde profiles","volume":"31","author":"Shangguan","year":"2013","journal-title":"Ann. Geophys."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1990","DOI":"10.1002\/2017JD027748","article-title":"Adaptive Node Parameterization for Dynamic Determination of Boundaries and Nodes of GNSS Tomographic Models","volume":"123","author":"Ding","year":"2018","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1029\/RS022i003p00379","article-title":"Estimation of tropospheric delay for microwaves from surface weather data","volume":"22","author":"Askne","year":"1987","journal-title":"Radio Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"833","DOI":"10.1002\/2015JD024181","article-title":"Water vapor-weighted mean temperature and its impact on the determination of precipitable water vapor and its linear trend","volume":"121","author":"Wang","year":"2016","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"301","DOI":"10.2151\/jmsj.2004.301","article-title":"Tsukuba GPS Dense Net Campaign Observation: Improvement in GPS Analysis of Slant Path Delay by Stacking One-way Postfit Phase Residuals","volume":"82","author":"Shoji","year":"2004","journal-title":"J. Meteorol. Soc. Jpn."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2183","DOI":"10.5194\/amt-10-2183-2017","article-title":"Inter-technique validation of tropospheric slant total delays","volume":"10","author":"Dick","year":"2017","journal-title":"Atmos. Meas. Tech."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1016\/0020-0190(72)90045-2","article-title":"An efficient algorith for determining the convex hull of a finite planar set","volume":"1","author":"Graham","year":"1972","journal-title":"Inf. Process. Lett."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"311","DOI":"10.5194\/angeo-35-311-2017","article-title":"New parameterized model for GPS water vapor tomography","volume":"35","author":"Ding","year":"2017","journal-title":"Ann. Geophys."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/4\/617\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T08:57:22Z","timestamp":1760173042000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/4\/617"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,13]]},"references-count":25,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2020,2]]}},"alternative-id":["rs12040617"],"URL":"https:\/\/doi.org\/10.3390\/rs12040617","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,2,13]]}}}