{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,2]],"date-time":"2026-07-02T23:23:13Z","timestamp":1783034593762,"version":"3.54.6"},"reference-count":21,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2019,9,11]],"date-time":"2019-09-11T00:00:00Z","timestamp":1568160000000},"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>The number of Android devices enabling access to raw GNSS (Global Navigation Satellite System) measurements is rapidly increasing, thanks to the dedicated Google APIs. In this study, the Xiaomi Mi8, the first GNSS dual-frequency smartphone embedded with the Broadcom BCM47755 GNSS chipset, was employed by leveraging the features of L5\/E5a observations in addition to the traditional L1\/E1 observations. The aim of this paper is to present two different smartphone applications in Geoscience, both based on the variometric approach and able to work in real time. In particular, tests using both VADASE (Variometric Approach for Displacement Analysis Stand-alone Engine) to retrieve the 3D velocity of a stand-alone receiver in real-time, and VARION (Variometric Approach for Real-Time Ionosphere Observations) algorithms, able to reconstruct real-time sTEC (slant total electron content) variations, were carried out. The results demonstrate the contribution that mass-market devices can offer to the geosciences. In detail, the noise level obtained with VADASE in a static scenario\u2014few mm\/s for the horizontal components and around 1 cm\/s for the vertical component\u2014underlines the possibility, confirmed from kinematic tests, of detecting fast movements such as periodic oscillations caused by earthquakes. VARION results indicate that the noise level can be brought back to that of geodetic receivers, making the Xiaomi Mi8 suitable for real-time ionosphere monitoring.<\/jats:p>","DOI":"10.3390\/rs11182113","type":"journal-article","created":{"date-parts":[[2019,9,11]],"date-time":"2019-09-11T11:26:34Z","timestamp":1568201194000},"page":"2113","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":42,"title":["Real-Time Geophysical Applications with Android GNSS Raw Measurements"],"prefix":"10.3390","volume":"11","author":[{"given":"Marco","family":"Fortunato","sequence":"first","affiliation":[{"name":"Geodesy and Geomatics Division, DICEA, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michela","family":"Ravanelli","sequence":"additional","affiliation":[{"name":"Geodesy and Geomatics Division, DICEA, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1059-6675","authenticated-orcid":false,"given":"Augusto","family":"Mazzoni","sequence":"additional","affiliation":[{"name":"Geodesy and Geomatics Division, DICEA, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,9,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Realini, E., Caldera, S., Pertusini, L., and Sampietro, D. (2017). Precise gnss positioning using smart devices. Sensors, 17.","DOI":"10.3390\/s17102434"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Privat, A., Pascaud, M., and Laurichesse, D. (June, January 28). Innovative smartphone applications for Precise Point Positioning. Proceedings of the 2018 SpaceOps Conference, Palais du Pharo Marseille, France.","DOI":"10.2514\/6.2018-2324"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Fortunato, M., Critchley-Marrows, J., Siutkowska, M., Ivanovici, M.L., Benedetti, E., and Roberts, W. (2019, January 9\u201312). Enabling High Accuracy Dynamic Applications in Urban Environments Using PPP and RTK on Android Multi-Frequency and Multi-GNSS Smartphones. Proceedings of the 2019 European Navigation Conference (ENC), Warsaw, Poland.","DOI":"10.1109\/EURONAV.2019.8714140"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Wu, Q., Sun, M., Zhou, C., and Zhang, P. (2019). Precise Point Positioning Using Dual-Frequency GNSS Observations on Smartphone. Sensors, 19.","DOI":"10.3390\/s19092189"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2358","DOI":"10.1016\/j.asr.2019.01.004","article-title":"Quality analysis of multi-GNSS raw observations and a velocity-aided positioning approach based on smartphones","volume":"63","author":"Liu","year":"2019","journal-title":"Adv. Space Res."},{"key":"ref_6","unstructured":"Pesyna, K.M., Heath, R.W., and Humphreys, T.E. (2014, January 8\u201312). Centimeter positioning with a smartphone-quality GNSS antenna. Proceedings of the 27th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS 2014, Tampa, FL, USA."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1007\/s10291-019-0892-5","article-title":"Signal characterization and assessment of code GNSS positioning with low-power consumption smartphones","volume":"23","author":"Paziewski","year":"2019","journal-title":"GPS Solut."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1007\/s10291-018-0736-8","article-title":"Quality assessment of GNSS observations from an Android N smartphone and positioning performance analysis using time-differenced filtering approach","volume":"22","author":"Zhang","year":"2018","journal-title":"GPS Solut."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Colosimo, G., Crespi, M., and Mazzoni, A. (2011). Real-time GPS seismology with a stand-alone receiver: A preliminary feasibility demonstration. J. Geophys. Res. Solid Earth, 116.","DOI":"10.1029\/2010JB007941"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"055801","DOI":"10.1088\/1361-6501\/ab0b87","article-title":"Data assimilation of GPS-ZTD into the RAMS model through 3D-Var: preliminary results at the regional scale","volume":"30","author":"Mascitelli","year":"2019","journal-title":"Meas. Sci. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"46607","DOI":"10.1038\/srep46607","article-title":"Real-time detection of tsunami ionospheric disturbances with a stand-alone GNSS receiver: A preliminary feasibility demonstration","volume":"7","author":"Savastano","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"e1501055","DOI":"10.1126\/sciadv.1501055","article-title":"MyShake: A smartphone seismic network for earthquake early warning and beyond","volume":"2","author":"Kong","year":"2016","journal-title":"Sci. Adv."},{"key":"ref_13","unstructured":"Colosimo, G. (2013). VADASE: A Brand New Approach to Real-Time GNSS Seismology, Lap Lambert Academic Publishing GmbH & Co KG."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1785\/0220130094","article-title":"Global Navigation Satellite Systems seismology for the 2012 M w 6.1 Emilia earthquake: Exploiting the VADASE algorithm","volume":"85","author":"Benedetti","year":"2014","journal-title":"Seismol. Res. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Fratarcangeli, F., Savastano, G., D\u2019Achille, M., Mazzoni, A., Crespi, M., Riguzzi, F., Devoti, R., and Pietrantonio, G. (2018). VADASE reliability and accuracy of real-time displacement estimation: Application to the Central Italy 2016 earthquakes. Remote. Sens., 10.","DOI":"10.3390\/rs10081201"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Pirazzi, G., Mazzoni, A., Biagi, L., and Crespi, M. (2017, January 25\u201329). Preliminary performance analysis with a GPS+ Galileo enabled chipset embedded in a smartphone. Proceedings of the ION GNSS, Portland, OR, USA.","DOI":"10.33012\/2017.15260"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1109\/TAES.1987.310829","article-title":"Ionospheric time-delay algorithm for single-frequency GPS users","volume":"AES-23","author":"Klobuchar","year":"1987","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1007\/s12210-018-0708-5","article-title":"The variometric approach to real-time high-frequency geodesy","volume":"29","author":"Fratarcangeli","year":"2018","journal-title":"Rend. Lincei Sci. Fis. Nat."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Savastano, G., Komjathy, A., Shume, E., Vergados, P., Ravanelli, M., Verkhoglyadova, O., Meng, X., and Crespi, M. (2019). Advantages of Geostationary Satellites for Ionospheric Anomaly Studies: Ionospheric Plasma Depletion Following a Rocket Launch. Remote. Sens., 11.","DOI":"10.3390\/rs11141734"},{"key":"ref_20","unstructured":"(2019, September 10). GitHub VARION. Available online: https:\/\/github.com\/giorgiosavastano\/VARION."},{"key":"ref_21","unstructured":"(2019, September 10). Rinex ON on Play Store. Available online: https:\/\/play.google.com\/store\/apps\/details?id=com.eu.nsl.rinexON&hl=it."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/18\/2113\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:18:43Z","timestamp":1760188723000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/18\/2113"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,9,11]]},"references-count":21,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2019,9]]}},"alternative-id":["rs11182113"],"URL":"https:\/\/doi.org\/10.3390\/rs11182113","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,9,11]]}}}