{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T11:37:14Z","timestamp":1761824234953,"version":"build-2065373602"},"reference-count":24,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2020,9,10]],"date-time":"2020-09-10T00:00:00Z","timestamp":1599696000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000844","name":"European Space Agency","doi-asserted-by":"publisher","award":["4000123436\/NL\/FF\/gp"],"award-info":[{"award-number":["4000123436\/NL\/FF\/gp"]}],"id":[{"id":"10.13039\/501100000844","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000270","name":"Natural Environment Research Council","doi-asserted-by":"publisher","award":["NE\/N018095\/1"],"award-info":[{"award-number":["NE\/N018095\/1"]}],"id":[{"id":"10.13039\/501100000270","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The UK\u2019s TechDemoSat-1 (TDS-1), launched 2014, has demonstrated the use of global positioning system (GPS) signals for monitoring ocean winds and sea ice. Here it is shown, for the first time, that Galileo and BeiDou signals detected by TDS-1 show similar promise. TDS-1 made seven raw data collections, recovering returns from Galileo and BeiDou, between November 2015 and March 2019. The retrieved open ocean delay Doppler maps (DDMs) are similar to those from GPS. Over sea ice, the Galileo DDMs show a distinctive triple peak. Analysis, adapted from that for GPS DDMs, gives Galileo\u2019s signal-to-noise ratio (SNR), which is found to be inversely sensitive to wind speed, as for GPS. A Galileo track transiting from open ocean to sea ice shows a strong instantaneous SNR response. These results demonstrate the potential of future spaceborne constellations of GNSS-R (global navigation satellite system\u2013reflectometry) instruments for exploiting signals from multiple systems: GPS, Galileo, and BeiDou.<\/jats:p>","DOI":"10.3390\/rs12182927","type":"journal-article","created":{"date-parts":[[2020,9,10]],"date-time":"2020-09-10T09:10:09Z","timestamp":1599729009000},"page":"2927","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["First Assessment of Geophysical Sensitivities from Spaceborne Galileo and BeiDou GNSS-Reflectometry Data Collected by the UK TechDemoSat-1 Mission"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8918-2351","authenticated-orcid":false,"given":"Matthew L.","family":"Hammond","sequence":"first","affiliation":[{"name":"National Oceanography Centre, Southampton SO14 3ZH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1507-2133","authenticated-orcid":false,"given":"Giuseppe","family":"Foti","sequence":"additional","affiliation":[{"name":"National Oceanography Centre, Southampton SO14 3ZH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4277-4894","authenticated-orcid":false,"given":"Jonathan","family":"Rawlinson","sequence":"additional","affiliation":[{"name":"Surrey Satellite Technology Ltd., Guildford GU2 7YE, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christine","family":"Gommenginger","sequence":"additional","affiliation":[{"name":"National Oceanography Centre, Southampton SO14 3ZH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7347-7411","authenticated-orcid":false,"given":"Meric","family":"Srokosz","sequence":"additional","affiliation":[{"name":"National Oceanography Centre, Southampton SO14 3ZH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3758-7688","authenticated-orcid":false,"given":"Lucinda","family":"King","sequence":"additional","affiliation":[{"name":"Surrey Satellite Technology Ltd., Guildford GU2 7YE, UK"},{"name":"Surrey Space Centre, University of Surrey, Guildford GU2 7XH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Martin","family":"Unwin","sequence":"additional","affiliation":[{"name":"Surrey Satellite Technology Ltd., Guildford GU2 7YE, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Josep","family":"Rosell\u00f3","sequence":"additional","affiliation":[{"name":"European Space Agency, ESTEC, 2201 AZ Noordwijk, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,9,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"515","DOI":"10.1175\/1520-0426(2004)021<0515:ROOSWS>2.0.CO;2","article-title":"Retrieval of ocean surface wind speed and wind direction using reflected GPS signals","volume":"21","author":"Komjathy","year":"2004","journal-title":"J. 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