{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,17]],"date-time":"2026-07-17T14:54:30Z","timestamp":1784300070488,"version":"3.55.0"},"reference-count":33,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2019,9,1]],"date-time":"2019-09-01T00:00:00Z","timestamp":1567296000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Two estimation methods using a dual GNSS (Global Navigation Satellite System) receiver system are proposed. The dual-frequency combination method combines the carrier phase observations of dual-frequency signals, whereas the single-frequency combination method combines the pseudorange and carrier phase observations of a single-frequency signal, both of which are geometry-free strictly combination and free of the effect of ionospheric delay. Theoretical models are established in the offline phase to describe the relationship between the spectral peak frequency of the combined sequence and the antenna height. A field experiment was conducted recently and the data processing results show that the root mean squared error (RMSE) of the dual-frequency combination method is 5.04 cm with GPS signals and 6.26 cm with BDS signals, which are slightly greater than the RMSE of 4.16 cm produced by the single-frequency combination method of L1 band with GPS signals. The results also demonstrate that the proposed two combination methods and the SNR method achieve similar performance. A dual receiver system enables the better use of GNSS signal carrier phase observations for snow depth estimation, achieving increased data utilization.<\/jats:p>","DOI":"10.3390\/rs11172056","type":"journal-article","created":{"date-parts":[[2019,9,2]],"date-time":"2019-09-02T03:16:12Z","timestamp":1567394172000},"page":"2056","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Snow Depth Estimation with GNSS-R Dual Receiver Observation"],"prefix":"10.3390","volume":"11","author":[{"given":"Kegen","family":"Yu","sequence":"first","affiliation":[{"name":"School of Environmental Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China"},{"name":"School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shuyao","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4011-2018","authenticated-orcid":false,"given":"Yunwei","family":"Li","sequence":"additional","affiliation":[{"name":"School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xin","family":"Chang","sequence":"additional","affiliation":[{"name":"School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiancheng","family":"Li","sequence":"additional","affiliation":[{"name":"School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,9,1]]},"reference":[{"key":"ref_1","first-page":"461","article-title":"Snow and climate: Physical processes, surface energy exchange and modeling","volume":"29","author":"Armstrong","year":"2010","journal-title":"Polar Res."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Qian, Y., Gustafson, W.I., Leung, L.R., and Ghan, S.J. (2009). Effects of soot-induced snow albedo change on snowpack and hydrological cycle in western United States based on Weather Research and Forecasting chemistry and regional climate simulations. J. Geophys. Res. Atmos., 114.","DOI":"10.1029\/2008JD011039"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Qian, Y., Flanner, M.G., Leung, L., and Wang, W. (2010). Impacts of Tibetan Plateau snowpack pollution on the Asian hydrological cycle and monsoon climate. Atmos. Chem. Phys., 10.","DOI":"10.5194\/acpd-10-22855-2010"},{"key":"ref_4","first-page":"331","article-title":"A passive reflectometry and interferometry system (Paris): Application to ocean altimetry","volume":"17","year":"1993","journal-title":"ESA J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1229","DOI":"10.1109\/TGRS.2005.845643","article-title":"Detection and processing of bistatically reflected GPS signals from a low Earth orbit for the purpose of ocean remote sensing","volume":"43","author":"Gleason","year":"2005","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Carreno-Luengo, H., Lowe, S.T., Zuffada, C., Esterhuizen, S., and Oveisgharan, S. (2017). Spaceborne GNSS-R from the SMAP mission; first assessment of polarimetric scatterometry over land and cryosphere. Remote Sens., 9.","DOI":"10.3390\/rs9040362"},{"key":"ref_7","unstructured":"Auber, J.C., Bilbaut, A., and Rigal, L. (1994, January 20\u201323). Characterization of Multipath on Land and Sea at GPS Frequencies. Proceedings of the ION-GPS-94 Conference, Paris, France."},{"key":"ref_8","first-page":"44","article-title":"A GPS tide gauge","volume":"6","author":"Anderson","year":"1995","journal-title":"GPS World Showcase"},{"key":"ref_9","unstructured":"Katzberg, S.J., and Garrison, J.J.L. (1996). Utilizing GPS to Determine Ionospheric Delay Over the Ocean, NASA Langley Technical Report Server."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"951","DOI":"10.1109\/36.841977","article-title":"Scattering of GPS signals from the ocean with wind remote sensing application","volume":"38","author":"Zavorotny","year":"2000","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2112","DOI":"10.1109\/TGRS.2011.2172797","article-title":"Phase altimetry with dual polarization GNSS-R over sea ice","volume":"50","author":"Fabra","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"4561","DOI":"10.1109\/TGRS.2011.2151864","article-title":"Detection of a Sea Surface Salinity Gradient Using Data Sets of Airborne Synthetic Aperture Radiometer HUT-2-D and a GNSS-R Instrument","volume":"49","author":"Welk","year":"2011","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1109\/JSTARS.2012.2210392","article-title":"Using GNSS-R Imaging of the Ocean Surface for Oil Slick Detection","volume":"6","author":"Valencia","year":"2013","journal-title":"IEEE J. Sel. Topics Appl. Earth Observ."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1016\/j.rse.2004.05.016","article-title":"Initial results of land-reflected GPS bistatic radar measurements in SMEX02","volume":"92","author":"Masters","year":"2004","journal-title":"Remote Sens. Environ."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1522","DOI":"10.1109\/JSTARS.2014.2322854","article-title":"Airborne GNSS-R Polarimetric Measurements for Soil Moisture and Above-Ground Biomass Estimation","volume":"7","author":"Egido","year":"2014","journal-title":"IEEE J. Sel. Topics Appl. Earth Observ."},{"key":"ref_16","first-page":"71","article-title":"Land Geophysical Parameters Retrieval Using the Interference Pattern GNSS-R Technique","volume":"49","author":"Camps","year":"2010","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"282","DOI":"10.1109\/LGRS.2011.2166242","article-title":"Vegetation Water Content Estimation Using GNSS Measurements","volume":"9","author":"Camps","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"28287","DOI":"10.3390\/s151128287","article-title":"Prototyping a GNSS-Based Passive Radar for UAVs: An Instrument to Classify the Water Content Feature of Lands","volume":"15","author":"Gamba","year":"2015","journal-title":"Sensors"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2657","DOI":"10.1002\/grl.50556","article-title":"A new way to detect volcanic plumes","volume":"40","author":"Larson","year":"2013","journal-title":"Geophys. Res. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1823","DOI":"10.1016\/j.asr.2010.04.025","article-title":"Forest biomass monitoring with GNSS-R: Theoretical simulations","volume":"47","author":"Ferrazzoli","year":"2011","journal-title":"Adv. Space Res."},{"key":"ref_21","first-page":"876","article-title":"Can we measure snow depth with GPS receivers?","volume":"21","author":"Larson","year":"2009","journal-title":"Geophys. Res. Lett."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"209","DOI":"10.1007\/s00190-011-0511-x","article-title":"GPS snow depth meter with geometry-free linear combinations of carrier phases","volume":"86","author":"Ozeki","year":"2012","journal-title":"J. Geod."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"5100","DOI":"10.1109\/TGRS.2015.2417214","article-title":"Snow depth estimation based on multipath phase combination of GPS triple-frequency signals","volume":"53","author":"Yu","year":"2015","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"4817","DOI":"10.1109\/JSTARS.2016.2560763","article-title":"Estimation of Snow Depth from GLONASS SNR and Phase-Based Multipath Reflectometry","volume":"9","author":"Qian","year":"2016","journal-title":"IEEE J. Sel. Top. Appl. Earth Observ."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1817","DOI":"10.1109\/TGRS.2018.2869284","article-title":"Snow Depth Estimation Based on Combination of Pseudorange and Carrier Phase of GNSS Dual-Frequency Signals","volume":"57","author":"Yu","year":"2019","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Hinrikus, H. (2006). Electromagnetic Waves, Wiley Encyclopedia of Biomedical Engineering.","DOI":"10.1002\/9780471740360.ebs0424"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1029\/2007RS003652","article-title":"Mapping the gps multipath environment using the signal-to-noise ratio (SNR)","volume":"42","author":"Bilich","year":"2007","journal-title":"Radio Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1007\/s10291-013-0331-y","article-title":"Forward modeling of GPS multipath for near-surface reflectometry and positioning applications","volume":"18","author":"Nievinski","year":"2014","journal-title":"GPS Solut."},{"key":"ref_29","unstructured":"Axelrad, P., Larson, K., and Jones, B. (2005, January 13\u201316). Use of the correct satellite repeat period to characterize and reduce site-specific multipath errors. Proceedings of the 18th Intnational Technical Meeting Satellite Division Institute Navigation (ION GNSS), Long Beach, CA, USA."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1007\/BF02106512","article-title":"The Global Positioning System: Signals, measurements, and performance","volume":"1","author":"Enge","year":"1994","journal-title":"Int. J. Wirel. Inf. Netw."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1007\/BF00648343","article-title":"Least-squares frequency analysis of unequally spaced data","volume":"39","author":"Lomb","year":"1976","journal-title":"Astrophys. Space Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1086\/160554","article-title":"Studies in astronomical time series analysis. II\u2014Statistical aspects of spectral analysis of unevenly spaced data","volume":"263","author":"Scargle","year":"1982","journal-title":"Astrophys. J."},{"key":"ref_33","unstructured":"Hofmann-Wellenhof, B., Lichtenegger, H., and Wasle, E. (2008). GNSS\u2014Global Navigation Satellite Systems: GPS, GLONASS Galileo and More, Springer."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/17\/2056\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:15:53Z","timestamp":1760188553000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/17\/2056"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,9,1]]},"references-count":33,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2019,9]]}},"alternative-id":["rs11172056"],"URL":"https:\/\/doi.org\/10.3390\/rs11172056","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,9,1]]}}}