{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,12]],"date-time":"2026-06-12T10:22:40Z","timestamp":1781259760983,"version":"3.54.1"},"reference-count":37,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2020,1,9]],"date-time":"2020-01-09T00:00:00Z","timestamp":1578528000000},"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":["41804008, 41474007, and 41574005"],"award-info":[{"award-number":["41804008, 41474007, and 41574005"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Primary Research and Development Plan of Hunan Province","award":["2016SK2002"],"award-info":[{"award-number":["2016SK2002"]}]},{"name":"Major Projects of High Resolution Earth Observation System of China (Civil Part)","award":["03-Y20A11-9001-15\/16"],"award-info":[{"award-number":["03-Y20A11-9001-15\/16"]}]},{"name":"Innovation Foundation for Postgraduate of Central South University, China","award":["2017zzts550"],"award-info":[{"award-number":["2017zzts550"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Interferometric baseline estimation is a key procedure of interferometric synthetic aperture radar (SAR) data processing. The error of the interferometric baseline affects not only the removal of the flat-earth phase, but also the transformation coefficient between the topographic phase and elevation, which will affect the topographic phase removal for differential interferometric SAR (D-InSAR) and the accuracy of the final generated digital elevation model (DEM) product for interferometric synthetic aperture (InSAR). To obtain a highly accurate interferometric baseline, this paper firstly investigates the geometry of InSAR imaging and establishes a rigorous relationship between the interferometric baseline and the flat-earth phase. Then, a baseline refinement method without a ground control point (GCP) is proposed, where a relevant theoretical model and resolving method are developed. Synthetic and real SAR datasets are used in the experiments, and a comparison with the conventional least-square (LS) baseline refinement method is made. The results demonstrate that the proposed method exhibits an obvious improvement over the conventional LS method, with percentages of up to 51.5% in the cross-track direction. Therefore, the proposed method is effective and advantageous.<\/jats:p>","DOI":"10.3390\/rs12020233","type":"journal-article","created":{"date-parts":[[2020,1,10]],"date-time":"2020-01-10T04:06:51Z","timestamp":1578629211000},"page":"233","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["SAR Interferometric Baseline Refinement Based on Flat-Earth Phase without a Ground Control Point"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2047-2326","authenticated-orcid":false,"given":"Bing","family":"Xu","sequence":"first","affiliation":[{"name":"School of Geoscience and Info-Physics, Central South University, Changsha 410083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4575-5258","authenticated-orcid":false,"given":"Zhiwei","family":"Li","sequence":"additional","affiliation":[{"name":"School of Geoscience and Info-Physics, Central South University, Changsha 410083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yan","family":"Zhu","sequence":"additional","affiliation":[{"name":"School of Geoscience and Info-Physics, Central South University, Changsha 410083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiancun","family":"Shi","sequence":"additional","affiliation":[{"name":"School of Geoscience and Info-Physics, Central South University, Changsha 410083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guangcai","family":"Feng","sequence":"additional","affiliation":[{"name":"School of Geoscience and Info-Physics, Central South University, Changsha 410083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1007\/BF00561997","article-title":"A new earth-based radar technique for the measurement of lunar topography","volume":"4","author":"Zisk","year":"1972","journal-title":"Moon"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"9183","DOI":"10.1029\/JB094iB07p09183","article-title":"Mapping small elevation changes over large areas: Differential radar interferometry","volume":"94","author":"Gabriel","year":"1989","journal-title":"J. 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