{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T06:25:11Z","timestamp":1771482311339,"version":"3.50.1"},"reference-count":31,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2016,12,11]],"date-time":"2016-12-11T00:00:00Z","timestamp":1481414400000},"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":["ESTEC RFP\/IPL-PTE\/FE\/yc\/1157\/2015"],"award-info":[{"award-number":["ESTEC RFP\/IPL-PTE\/FE\/yc\/1157\/2015"]}],"id":[{"id":"10.13039\/501100000844","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Spanish Ministry of Economy and Competitiveness","award":["ESP2015-70014-C2-2-R"],"award-info":[{"award-number":["ESP2015-70014-C2-2-R"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The interferometric Global Navigation Satellite System Reflectometry (iGNSS-R) exploits the full spectrum of the transmitted GNSS signal to improve the ranging performance for sea surface height applications. The Inter-Modulation (IM) component of the GNSS signals is an additional component that keeps the power envelope of the composite signals constant. This extra component has been neglected in previous studies on iGNSS-R, in both modelling and instrumentation. This letter takes the GPS L1 signal as an example to analyse the impact of the IM component on iGNSS-R ocean altimetry, including signal-to-noise ratio, the altimetric sensitivity and the final altimetric precision. Analytical results show that previous estimates of the final altimetric precision were underestimated by a factor of     1 . 5 \u223c 1 . 7     due to the negligence of the IM component, which should be taken into account in proper design of the future spaceborne iGNSS-R altimetry missions.<\/jats:p>","DOI":"10.3390\/rs8121013","type":"journal-article","created":{"date-parts":[[2016,12,12]],"date-time":"2016-12-12T14:43:57Z","timestamp":1481553837000},"page":"1013","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["The Impact of Inter-Modulation Components on Interferometric GNSS-Reflectometry"],"prefix":"10.3390","volume":"8","author":[{"given":"Weiqiang","family":"Li","sequence":"first","affiliation":[{"name":"Earth Observation Research Group, Institut de Ci\u00e8ncies de l\u2019Espai (CSIC\/IEEC), Barcelona 08193, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5947-2649","authenticated-orcid":false,"given":"Antonio","family":"Rius","sequence":"additional","affiliation":[{"name":"Earth Observation Research Group, Institut de Ci\u00e8ncies de l\u2019Espai (CSIC\/IEEC), Barcelona 08193, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fran","family":"Fabra","sequence":"additional","affiliation":[{"name":"Earth Observation Research Group, Institut de Ci\u00e8ncies de l\u2019Espai (CSIC\/IEEC), Barcelona 08193, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manuel","family":"Mart\u00edn-Neira","sequence":"additional","affiliation":[{"name":"European Space Research and Technology Centre, European Space Agency, Noordwijk 2200 AG, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8908-0972","authenticated-orcid":false,"given":"Estel","family":"Cardellach","sequence":"additional","affiliation":[{"name":"Earth Observation Research Group, Institut de Ci\u00e8ncies de l\u2019Espai (CSIC\/IEEC), Barcelona 08193, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9173-8355","authenticated-orcid":false,"given":"Serni","family":"Rib\u00f3","sequence":"additional","affiliation":[{"name":"Earth Observation Research Group, Institut de Ci\u00e8ncies de l\u2019Espai (CSIC\/IEEC), Barcelona 08193, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dongkai","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University (BUAA), Beijing 100191, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,12,11]]},"reference":[{"key":"ref_1","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_2","doi-asserted-by":"crossref","unstructured":"Lowe, S.T., Zuffada, C., Chao, Y., Kroger, P., Young, L.E., and LaBrecque, J.L. 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