{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,26]],"date-time":"2026-02-26T15:24:36Z","timestamp":1772119476751,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2021,8,16]],"date-time":"2021-08-16T00:00:00Z","timestamp":1629072000000},"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":["41730109"],"award-info":[{"award-number":["41730109"]}],"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":["41874040"],"award-info":[{"award-number":["41874040"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012176","name":"Program of Introducing Talents of Discipline to Universities","doi-asserted-by":"publisher","award":["B20046"],"award-info":[{"award-number":["B20046"]}],"id":[{"id":"10.13039\/501100012176","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Real-time precise point positioning (RT-PPP) has become a powerful technique for the determination of the zenith tropospheric delay (ZTD) over a GPS (global positioning system) or GNSS (global navigation satellite systems) station of interest, and the follow-on high-precision retrieval of precipitable water vapor (PWV). The a priori zenith hydrostatic delay (ZHD) and the mapping function used in the PPP approach are the two factors that could affect the accuracy of the PPP-based ZTD significantly. If the in situ atmospheric pressure is available, the Saastamoinen model can be used to determine ZHD values, and the model-predicted ZHD results are of high accuracy. However, not all GPS\/GNSS are equipped with an in situ meteorological sensor. In this research, the daily forecasting ZHD and mapping function values from VMF1 forecasting (VMF1_FC) and VMF3 forecasting (VMF3_FC) products were used for the determination of the GPS-derived PWV. The a priori ZHDs derived from VMF1_FC and VMF3_FC were first evaluated by comparing against the reference ZHDs from globally distributed radiosonde stations. GPS observations from 41 IGS stations that have co-located radiosonde stations during the period of the first half of 2020 were used to test the quality of GPS-ZTD and GPS-PWV. Three sets of ZTDs estimated from RT-PPP solutions using the a priori ZHD and mapping function from the following three VMF products were evaluated: (1) VMF1_FC; (2) VMF3_FC (resolution 5\u00b0 \u00d7 5\u00b0); (3) VMF3_FC (resolution 1\u00b0 \u00d7 1\u00b0). The results showed that, when the ZHDs from 443 globally distributed radiosonde stations from 1 July 2018 to 30 June 2021 were used as the reference, the mean RMSEs of the ZHDs from the three VMF products were 5.9, 5.4, and 4.3 mm, respectively. The ZTDs estimated from RT-PPP at 41 selected IGS stations were compared with those from IGS, and the results showed that the mean RMSEs of the ZTDs of the 41 stations from the three PPP solutions were 8.6, 9.0, and 8.6 mm, respectively, and the mean RMSEs of the PWV converted from their corresponding ZWDs were 1.9, 2.4, and 1.7 mm, respectively, in comparison with the reference PWV from co-located radiosonde stations. The results suggest that the a priori ZHD and mapping function from VMF1_FC and VMF3_FC can be used for the precise determination of real-time GPS\/GNSS-PWV in most regions, especially the VMF3_FC (resolution 1\u00b0 \u00d7 1\u00b0) product.<\/jats:p>","DOI":"10.3390\/rs13163245","type":"journal-article","created":{"date-parts":[[2021,8,16]],"date-time":"2021-08-16T21:28:04Z","timestamp":1629149284000},"page":"3245","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Retrieving Precipitable Water Vapor from Real-Time Precise Point Positioning Using VMF1\/VMF3 Forecasting Products"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0607-6877","authenticated-orcid":false,"given":"Peng","family":"Sun","sequence":"first","affiliation":[{"name":"School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China"}]},{"given":"Kefei","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China"},{"name":"Satellite Positioning for Atmosphere, Climate, and Environment (SPACE) Research Centre, RMIT University, Melbourne, VIC 3001, Australia"}]},{"given":"Suqin","family":"Wu","sequence":"additional","affiliation":[{"name":"School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5380-0587","authenticated-orcid":false,"given":"Moufeng","family":"Wan","sequence":"additional","affiliation":[{"name":"School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China"}]},{"given":"Yun","family":"Lin","sequence":"additional","affiliation":[{"name":"Shenzhen Yunhai Exploration Technology Co., Ltd., Shenzhen 518100, China"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,16]]},"reference":[{"key":"ref_1","first-page":"L07304","article-title":"The Global Mapping Function (GMF): A New Empirical Mapping Function Based on Numerical Weather Model Data","volume":"33","author":"Niell","year":"2006","journal-title":"Geophys. Res. Lett."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"B02406","DOI":"10.1029\/2005JB003629","article-title":"Troposphere Mapping Functions for GPS and Very Long Baseline Interferometry from European Centre for Medium-Range Weather Forecasts Operational Analysis Data","volume":"111","author":"Boehm","year":"2006","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1387","DOI":"10.1007\/s00190-018-1127-1","article-title":"Refined Discrete and Empirical Horizontal Gradients in VLBI Analysis","volume":"92","author":"Landskron","year":"2018","journal-title":"J. Geod."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"5385","DOI":"10.5194\/amt-9-5385-2016","article-title":"Review of the State of the Art and Future Prospects of the Ground-Based GNSS Meteorology in Europe","volume":"9","author":"Guerova","year":"2016","journal-title":"Atmos. Meas. Tech."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"351","DOI":"10.2151\/jmsj.2004.351","article-title":"Rapid Retrieval and Assimilation of Ground Based GPS Precipitable Water Observations at the NOAA Forecast Systems Laboratory: Impact on Weather Forecasts","volume":"82","author":"Gutman","year":"2004","journal-title":"J. Meteorol. Soc. Jpn."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1569","DOI":"10.5194\/amt-12-1569-2019","article-title":"The Use of GNSS Zenith Total Delays in Operational AROME\/Hungary 3D-Var over a Central European Domain","volume":"12","author":"Mile","year":"2019","journal-title":"Atmos. Meas. Tech."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"414","DOI":"10.1016\/j.atmosres.2013.11.026","article-title":"Ground-Based GNSS ZTD\/IWV Estimation System for Numerical Weather Prediction in Challenging Weather Conditions","volume":"138","author":"Rohm","year":"2014","journal-title":"Atmos. Res."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1007\/s10291-014-0427-z","article-title":"Comparative Analysis of Real-Time Precise Point Positioning Zenith Total Delay Estimates","volume":"20","author":"Ahmed","year":"2016","journal-title":"GPS Solut."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1347","DOI":"10.1016\/j.asr.2014.02.021","article-title":"Real-Time Zenith Tropospheric Delays in Support of Numerical Weather Prediction Applications","volume":"53","author":"Dousa","year":"2014","journal-title":"Adv. Space Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3615","DOI":"10.1002\/2013GL058721","article-title":"Real-Time GPS Sensing of Atmospheric Water Vapor: Precise Point Positioning with Orbit, Clock, and Phase Delay Corrections","volume":"41","author":"Li","year":"2014","journal-title":"Geophys. Res. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3452","DOI":"10.1109\/TGRS.2014.2377041","article-title":"Real-Time GPS Precise Point Positioning-Based Precipitable Water Vapor Estimation for Rainfall Monitoring and Forecasting","volume":"53","author":"Shi","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"10044","DOI":"10.1002\/2014JD021486","article-title":"Real-Time Retrieval of Precipitable Water Vapor from GPS Precise Point Positioning: Real-Time Retrieval of PWV from GPS PPP","volume":"119","author":"Yuan","year":"2014","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_13","unstructured":"Hadas, T., and Hobiger, T. (2020). Benefits of Using Galileo for Real-Time GNSS Meteorology. IEEE Geosci. Remote Sens. Lett., 1\u20135."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"6385","DOI":"10.1109\/TGRS.2015.2438395","article-title":"Multi-GNSS Meteorology: Real-Time Retrieving of Atmospheric Water Vapor from BeiDou, Galileo, GLONASS, and GPS Observations","volume":"53","author":"Li","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"7897","DOI":"10.1029\/2018JD028320","article-title":"Real-Time Sensing of Precipitable Water Vapor from BeiDou Observations: Hong Kong and CMONOC Networks","volume":"123","author":"Li","year":"2018","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"843","DOI":"10.1007\/s00190-015-0818-0","article-title":"Real-Time Retrieval of Precipitable Water Vapor from GPS and BeiDou Observations","volume":"89","author":"Lu","year":"2015","journal-title":"J. Geod."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"703","DOI":"10.1007\/s10291-015-0479-8","article-title":"Estimation and Evaluation of Real-Time Precipitable Water Vapor from GLONASS and GPS","volume":"20","author":"Lu","year":"2016","journal-title":"GPS Solut."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Lu, C., Chen, X., Liu, G., Dick, G., Wickert, J., Jiang, X., Zheng, K., and Schuh, H. (2017). Real-Time Tropospheric Delays Retrieved from Multi-GNSS Observations and IGS Real-Time Product Streams. Remote Sens., 9.","DOI":"10.3390\/rs9121317"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"4743","DOI":"10.1109\/TGRS.2020.2966774","article-title":"Real-Time Retrieval of Precipitable Water Vapor from Galileo Observations by Using the MGEX Network","volume":"58","author":"Lu","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"17067","DOI":"10.1038\/s41598-018-35155-3","article-title":"Real-Time Tropospheric Delay Retrieval with GPS, GLONASS, Galileo and BDS Data","volume":"8","author":"Pan","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2779","DOI":"10.1002\/2016JD025727","article-title":"An Evaluation of Real-Time Troposphere Estimation Based on GNSS Precise Point Positioning","volume":"122","author":"Ding","year":"2017","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Lu, C., Li, X., Cheng, J., Dick, G., Ge, M., Wickert, J., and Schuh, H. (2018). Real-Time Tropospheric Delay Retrieval from Multi-GNSS PPP Ambiguity Resolution: Validation with Final Troposphere Products and a Numerical Weather Model. Remote Sens., 10.","DOI":"10.3390\/rs10030481"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1069","DOI":"10.1007\/s10291-016-0595-0","article-title":"Optimum Stochastic Modeling for GNSS Tropospheric Delay Estimation in Real-Time","volume":"21","author":"Hadas","year":"2017","journal-title":"GPS Solut."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1007\/s10291-020-01014-w","article-title":"Considering Different Recent Advancements in GNSS on Real-Time Zenith Troposphere Estimates","volume":"24","author":"Hadas","year":"2020","journal-title":"GPS Solut."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"747","DOI":"10.1007\/s00190-015-0811-7","article-title":"Impacts of Real-Time Satellite Clock Errors on GPS Precise Point Positioning-Based Troposphere Zenith Delay Estimation","volume":"89","author":"Shi","year":"2015","journal-title":"J. Geod."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1007\/s10291-020-0954-8","article-title":"The Impact of Second-Order Ionospheric Delays on the ZWD Estimation with GPS and BDS Measurements","volume":"24","author":"Zhang","year":"2020","journal-title":"GPS Solut."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Zhang, Z., Guo, F., and Zhang, X. (2018). The Effects of Higher-Order Ionospheric Terms on GPS Tropospheric Delay and Gradient Estimates. Remote Sens., 10.","DOI":"10.3390\/rs10101561"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Zhao, L., V\u00e1clavovic, P., and Dou\u0161a, J. (2020). Performance Evaluation of Troposphere Estimated from Galileo-Only Multi-Frequency Observations. Remote Sens., 12.","DOI":"10.3390\/rs12030373"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"963","DOI":"10.1002\/2017RS006254","article-title":"The Impact of Higher-Order Ionospheric Effects on Estimated Tropospheric Parameters in Precise Point Positioning: Higher-Order Ionospheric Effects","volume":"52","author":"Zus","year":"2017","journal-title":"Radio Sci."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1007\/s00190-007-0170-0","article-title":"Implementation and Testing of the Gridded Vienna Mapping Function 1 (VMF1)","volume":"82","author":"Kouba","year":"2008","journal-title":"J. Geod."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"L23303","DOI":"10.1029\/2006GL027706","article-title":"Impact of a Priori Zenith Hydrostatic Delay Errors on GPS Estimates of Station Heights and Zenith Total Delays","volume":"33","author":"Tregoning","year":"2006","journal-title":"Geophys. Res. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Saastamoinen, J. (1972). Atmospheric correction for the troposphere and stratosphere in radio ranging satellites. The Use of Artificial Satellites for Geodesy, American Geophysical Union (AGU).","DOI":"10.1029\/GM015p0247"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"679","DOI":"10.1007\/s00190-007-0135-3","article-title":"Short Note: A Global Model of Pressure and Temperature for Geodetic Applications","volume":"81","author":"Boehm","year":"2007","journal-title":"J. Geod."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1007\/s10291-014-0403-7","article-title":"Development of an Improved Empirical Model for Slant Delays in the Troposphere (GPT2w)","volume":"19","author":"Schindelegger","year":"2015","journal-title":"GPS Solut."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1069","DOI":"10.1002\/grl.50288","article-title":"GPT2: Empirical Slant Delay Model for Radio Space Geodetic Techniques","volume":"40","author":"Lagler","year":"2013","journal-title":"Geophys. Res. Lett."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2807","DOI":"10.5194\/amt-10-2807-2017","article-title":"Determination of Zenith Hydrostatic Delay and Its Impact on GNSS-Derived Integrated Water Vapor","volume":"10","author":"Wang","year":"2017","journal-title":"Atmos. Meas. Tech."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1007\/s00190-017-1066-2","article-title":"VMF3\/GPT3: Refined Discrete and Empirical Troposphere Mapping Functions","volume":"92","author":"Landskron","year":"2018","journal-title":"J. Geod."},{"key":"ref_38","unstructured":"(2021, July 26). Re3data.org: VMF Data Server Editing Status 2020-12-14; Re3data.Org-Registry of Research Data Repositories. Available online: https:\/\/vmf.geo.tuwien.ac.at."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.jastp.2018.05.002","article-title":"GGOS Tropospheric Delay Forecast Product Performance Evaluation and Its Application in Real-Time PPP","volume":"175","author":"Yao","year":"2018","journal-title":"J. Atmos. Sol.-Terr. Phys."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1501","DOI":"10.1007\/s00190-019-01263-9","article-title":"Assessment of Forecast Vienna Mapping Function 1 for Real-Time Tropospheric Delay Modeling in GNSS","volume":"93","author":"Yuan","year":"2019","journal-title":"J. Geod."},{"key":"ref_41","unstructured":"Weber, G., Mervart, L., and St\u00fcrze, A. (2016). BKG Ntrip Client (BNC): Version 2.12, Verlag des Bundesamtes f\u00fcr Kartographie und Geod\u00e4sie."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1593","DOI":"10.1029\/RS020i006p01593","article-title":"Geodesy by Radio Interferometry: Effects of Atmospheric Modeling Errors on Estimates of Baseline Length","volume":"20","author":"Davis","year":"1985","journal-title":"Radio Sci."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1007\/s00190-021-01535-3","article-title":"An Analysis of Multisource Tropospheric Hydrostatic Delays and Their Implications for GPS\/GLONASS PPP-Based Zenith Tropospheric Delay and Height Estimations","volume":"95","author":"Zhang","year":"2021","journal-title":"J. Geod."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"2529","DOI":"10.5194\/amt-14-2529-2021","article-title":"A New Global Grid-Based Weighted Mean Temperature Model Considering Vertical Nonlinear Variation","volume":"14","author":"Sun","year":"2021","journal-title":"Atmos. Meas. Tech."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/16\/3245\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:46:59Z","timestamp":1760165219000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/16\/3245"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,8,16]]},"references-count":44,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2021,8]]}},"alternative-id":["rs13163245"],"URL":"https:\/\/doi.org\/10.3390\/rs13163245","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,8,16]]}}}