{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:50:07Z","timestamp":1760237407610,"version":"build-2065373602"},"reference-count":17,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2020,4,10]],"date-time":"2020-04-10T00:00:00Z","timestamp":1586476800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Science Fund","award":["61701479"],"award-info":[{"award-number":["61701479"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Hybrid quadrature polarimetric (hybrid quad-pol) synthetic aperture radar (SAR) is proposed as a potential candidate for the full-polarimetric SAR mode. It allows balanced range ambiguity performance and simplified system structure. System based on hybrid-pol SAR mode can also implement the conventional quad-pol mode and the compact-pol mode via few adjustments. However, the azimuth ambiguity performance in cross-pol channels is proved deteriorated in hybrid quad-pol mode due to the lopsided energy distribution of ambiguities. As are generally called \u201cghost\u201d targets, azimuth ambiguities usually influence the recognition of the targets in SAR imaging. This letter describes how to remove the false targets that arise from azimuth ambiguities by means of waveform diversity and dual-focus post-processing (DFPP) technique. The proposed method exploits the feature of azimuth ambiguity and yields improved image quality in cross-pol channels with strong co-pol azimuth ambiguities removed in hybrid quad-pol SAR at a low system cost. Furthermore, it offers remarkable benefits for target detecting and recognition with strong false targets removed.<\/jats:p>","DOI":"10.3390\/rs12071226","type":"journal-article","created":{"date-parts":[[2020,4,13]],"date-time":"2020-04-13T10:41:52Z","timestamp":1586774512000},"page":"1226","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Azimuth Ambiguity Suppression for Hybrid Polarimetric Synthetic Aperture Radar via Waveform Diversity"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3287-914X","authenticated-orcid":false,"given":"Pengfei","family":"Zhao","sequence":"first","affiliation":[{"name":"Department of Space Microwave Remote Sensing System, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"University of the Chinese Academy of Sciences, Beijing 100039, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yunkai","family":"Deng","sequence":"additional","affiliation":[{"name":"Department of Space Microwave Remote Sensing System, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0373-3659","authenticated-orcid":false,"given":"Wei","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Space Microwave Remote Sensing System, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dacheng","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Space Microwave Remote Sensing System, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9850-7015","authenticated-orcid":false,"given":"Robert","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Space Microwave Remote Sensing System, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,10]]},"reference":[{"key":"ref_1","unstructured":"Cumming, I.G., and Wong, F.H. (2005). Digital Processing of Synthetic Aperture Radar Data: Algorithms and Implementation, Artech House."},{"key":"ref_2","unstructured":"Lee, J.S., and Pottier, E. (2009). Polarimetric Radar Imaging: From Basics to Applications, CRC Press."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"634","DOI":"10.1109\/TGRS.2004.842486","article-title":"Compact polarimetry based on symmetry properties of geophysical media: The pi\/4 mode","volume":"43","author":"Souyris","year":"2005","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3397","DOI":"10.1109\/TGRS.2007.895883","article-title":"Hybrid-Polarity SAR Architecture","volume":"45","author":"Raney","year":"2007","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1109\/TGRS.2011.2121075","article-title":"Improved Range Ambiguity Performance in Quad-Pol SAR","volume":"50","author":"Raney","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1016\/j.isprsjprs.2008.12.008","article-title":"Classification comparisons between dual-pol, compact polarimetric and quad-pol SAR imagery","volume":"64","author":"Ainsworth","year":"2009","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"861","DOI":"10.1109\/LGRS.2016.2550863","article-title":"Comparing Compact and Quadrature Polarimetric SAR Performance","volume":"13","author":"Raney","year":"2016","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"3287","DOI":"10.1109\/TGRS.2017.2667886","article-title":"New Insights Into Ambiguities in Quad-Pol SAR","volume":"55","author":"Villano","year":"2017","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"885","DOI":"10.1109\/36.239912","article-title":"Suppressing the azimuth ambiguities in synthetic aperture radar images","volume":"31","author":"Moreira","year":"1993","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"625","DOI":"10.1109\/TGRS.2004.842476","article-title":"Adaptive removal of azimuth ambiguities in SAR images","volume":"43","author":"Guarnieri","year":"2005","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3967","DOI":"10.1109\/JSTARS.2014.2320155","article-title":"Filtering of Azimuth Ambiguity in Stripmap Synthetic Aperture Radar Images","volume":"7","author":"Iodice","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Observ. Remote Ses."},{"key":"ref_12","unstructured":"Tao, Z., Armando, M., Weilin, Z., and Huilin, X. (2017, January 23\u201328). An Azimuth ambiguities removal method based on Polarimetric Notch Filter. Proceedings of the 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Fort Worth, TX, USA."},{"key":"ref_13","first-page":"564","article-title":"Digital Beamforming on Receive: Techniques and Optimization Strategies for High-Resolution Wide-Swath SAR Imaging","volume":"45","author":"Gebert","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Wen, X., Qiu, X., Han, B., Ding, C., Lei, B., and Chen, Q. (2018). A Range Ambiguity Suppression Processing Method for Spaceborne SAR with Up and Down Chirp Modulation. Sensors, 18.","DOI":"10.3390\/s18051454"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/LGRS.2018.2808196","article-title":"Nadir Echo Removal in Synthetic Aperture Radar via Waveform Diversity and Dual-Focus Postprocessing","volume":"15","author":"Villano","year":"2018","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_16","first-page":"1734","article-title":"Azimuth phase coding for range ambiguity suppression in SAR","volume":"3","author":"Dall","year":"2004","journal-title":"Proc. IGARSS"},{"key":"ref_17","unstructured":"Mittermayer, J., and Martinez, J.M. (2003, January 21\u201325). Analysis of range ambiguity suppression in SAR by up and down chirp modulation for point and distributed targets. Proceedings of the IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium (IEEE Cat. No.03CH37477), Toulouse, France."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/7\/1226\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:17:28Z","timestamp":1760174248000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/7\/1226"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,4,10]]},"references-count":17,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2020,4]]}},"alternative-id":["rs12071226"],"URL":"https:\/\/doi.org\/10.3390\/rs12071226","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2020,4,10]]}}}