{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:39:42Z","timestamp":1760236782888,"version":"build-2065373602"},"reference-count":41,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,12,30]],"date-time":"2021-12-30T00:00:00Z","timestamp":1640822400000},"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>Quadrature-polarimetric synthetic aperture radar (quad-pol SAR) has extensive applications, including climate zones classification, extraction of surface roughness, soil moisture mapping, moving target indication, and rice mapping. Hybrid quad-pol SAR ameliorates the range ambiguity performance of conventional quad-pol SAR. However, the azimuth ambiguity of its cross-polarized (cross-pol) echo signals is serious, limiting the swath width of SAR. Therefore, this paper proposes a spaceborne weighted amplitude modulation (WAM) full-polarimetric (full-pol) SAR system, and it can suppress the azimuth ambiguity of hybrid quad-pol SAR. The performance boost of the azimuth ambiguity by the two imaging modes of the proposed SAR system is detailed and evaluated with the L-band system parameters. Moreover, the chirp scaling algorithm (CSA) is adopted to execute scene simulations for the two imaging modes. The results indicate that the proposed SAR system can effectively suppress the azimuth ambiguity of hybrid quad-pol SAR and verify the theoretical analysis.<\/jats:p>","DOI":"10.3390\/rs14010155","type":"journal-article","created":{"date-parts":[[2021,12,30]],"date-time":"2021-12-30T23:29:07Z","timestamp":1640906947000},"page":"155","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["A Novel Weighted Amplitude Modulation (WAM) System for Ambiguity Suppression of Spaceborne Hybrid Quad-Pol SAR"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3497-4474","authenticated-orcid":false,"given":"Yanyan","family":"Zhang","sequence":"first","affiliation":[{"name":"Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100039, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1461-499X","authenticated-orcid":false,"given":"Sheng","family":"Chang","sequence":"additional","affiliation":[{"name":"Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100039, 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":"Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"National Key Laboratory of Microwave Imaging Technology, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peng","family":"Li","sequence":"additional","affiliation":[{"name":"Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100039, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yongwei","family":"Zhang","sequence":"additional","affiliation":[{"name":"Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yunkai","family":"Deng","sequence":"additional","affiliation":[{"name":"Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,30]]},"reference":[{"key":"ref_1","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_2","doi-asserted-by":"crossref","unstructured":"Raney, R.K. (2008, January 8\u201311). Hybrid-quad-pol SAR. Proceedings of the IGARSS 2008 IEEE International Geoscience and Remote Sensing Symposium, Boston, MA, USA.","DOI":"10.1109\/IGARSS.2008.4779765"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1109\/MAES.2016.160071","article-title":"Overview of radar waveform diversity","volume":"31","author":"Blunt","year":"2016","journal-title":"IEEE Aerosp. Electron. Syst. Mag."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1109\/7.993227","article-title":"Improved target classification using optimum polarimetric SAR signatures","volume":"38","author":"Sadjadi","year":"2002","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1921","DOI":"10.1109\/TAES.2010.5595604","article-title":"Radar Target Recognition Based on Modified Characteristic Polarization States","volume":"46","author":"Aldhubaib","year":"2010","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"5403","DOI":"10.1109\/TGRS.2015.2422134","article-title":"Optimization of the Degree of Polarization for Enhanced Ship Detection Using Polarimetric RADARSAT-2","volume":"53","author":"Touzi","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"McCormick, P., Jakabosky, J., Blunt, S.D., Allen, C., and Himed, B. (2015, January 10\u201315). Joint polarization\/waveform design and adaptive receive processing. Proceedings of the 2015 IEEE Radar Conference, Arlington, VA, USA.","DOI":"10.1109\/RADAR.2015.7131211"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2037","DOI":"10.1109\/TGRS.2011.2170576","article-title":"A Fully Polarimetric Characterization of the Impact of Precipitation on Short Wavelength Synthetic Aperture Radar","volume":"50","author":"Fritz","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"792","DOI":"10.1109\/TGRS.2004.843077","article-title":"Hydrometeor classification system using dual-polarization radar measurements: Mode improvements and in situ verification","volume":"43","author":"Lim","year":"2005","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Bringi, V.N., and Chandrasekar, V. (2001). Polarimetric Doppler Weather Radar: Principles and Applications, Cambridge University Press.","DOI":"10.1017\/CBO9780511541094"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Li, P., Zhao, F., Liu, D., Ou, N., Cao, C., Liu, X., Zhang, Y., Deng, Y., and Wang, R. (2021). First Demonstration of Hybrid Quad-Pol SAR Based on P-Band Airborne Experiment. IEEE Trans. Geosci. Remote Sens.","DOI":"10.1109\/TGRS.2021.3084959"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Zhang, R., Wang, Y., Hu, J., Yang, W., Chen, J., and Zhu, X.X. (2021). SAR4LCZ-Net: A Complex-valued Convolutional Neural Network for Local Climate Zones Classification Using Gaofen-3 Quad-pol SAR Data. IEEE Trans. Geosci. Remote Sens.","DOI":"10.1109\/TGRS.2021.3137911"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3480","DOI":"10.1109\/TGRS.2009.2022752","article-title":"Scale-dependent surface roughness behavior and its impact on empirical models for radar backscatter","volume":"47","author":"Campbell","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1718","DOI":"10.1109\/TGRS.2014.2346656","article-title":"Soil moisture estimation under tropical forests using UHF radar polarimetry","volume":"53","author":"Saatchi","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"3822","DOI":"10.1109\/TGRS.2019.2958488","article-title":"Preliminary Results of Multichannel SAR-GMTI Experiments for Airborne Quad-Pol Radar System","volume":"58","author":"Yang","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"3082","DOI":"10.1109\/JSTARS.2016.2586102","article-title":"Rice Mapping Using RADARSAT-2 Dual- and Quad-Pol Data in a Complex Land-Use Watershed: Cau River Basin (Vietnam)","volume":"9","author":"Hoang","year":"2016","journal-title":"IEEE J. Sel. Top. Appl. Earth Observ. Remote Sens."},{"key":"ref_17","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_18","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_19","doi-asserted-by":"crossref","unstructured":"Li, J., Ji, Y., Zhang, Y., Zhang, Q., and Dong, Z. (2018, January 13\u201315). Effects of Ionosphere Polarimetric Dispersion on Lower-Frequency Spaceborne SAR. Proceedings of the 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP), Shenzhen, China.","DOI":"10.1109\/SIPROCESS.2018.8600518"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"896","DOI":"10.1109\/LGRS.2012.2187271","article-title":"Impact of Azimuth Ambiguities on Interferometric Performance","volume":"9","author":"Villano","year":"2012","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_21","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 Obs. Remote Sens."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1066","DOI":"10.1109\/LGRS.2019.2892511","article-title":"A General Elliptical Formulation of Hybrid-POLSAR System Ambiguities","volume":"16","author":"Cloude","year":"2019","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Krieger, G., Gebert, N., and Moreira, A. (2007, January 4\u20138). Multidimensional waveform encoding for spaceborne synthetic aperture radar systems. Proceedings of the 2007 International Waveform Diversity and Design Conference, Pisa, Italy.","DOI":"10.1109\/WDDC.2007.4339427"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1109\/TGRS.2007.905974","article-title":"Multidimensional Waveform Encoding: A New Digital Beamforming Technique for Synthetic Aperture Radar Remote Sensing","volume":"46","author":"Krieger","year":"2008","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Krieger, G., Gebert, N., and Moreira, A. (2007, January 23\u201328). Multidimensional radar waveforms a new paradigm for the design and operation of highly performant spaceborne synthetic aperture radar systems. Proceedings of the 2007 IEEE International Geoscience and Remote Sensing Symposium, Barcelona, Spain.","DOI":"10.1109\/IGARSS.2007.4423969"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Krieger, G., Gebert, N., and Moreira, A. (2007, January 15\u201318). Multidimensional waveform encoding for synthetic aperture radar remote sensing. Proceedings of the 2007 IET International Conference on Radar Systems, Edinburgh, UK.","DOI":"10.1049\/cp:20070482"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Krieger, G., Gebert, N., Younis, M., and Moreira, A. (2008, January 26\u201330). Advanced synthetic aperture radar based on digital beamforming and waveform diversity. Proceedings of the 2008 IEEE Radar Conference, Rome, Italy.","DOI":"10.1109\/RADAR.2008.4720875"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Yang, C., Ou, N., Deng, Y., Liu, D., Zhang, Y., Wang, N., and Wang, R. (2021). Pattern Synthesis Algorithm for Range Ambiguity Suppression in the LT-1 Mission via Sequential Convex Optimizations. IEEE Trans. Geosci. Remote Sens.","DOI":"10.1109\/TGRS.2021.3099132"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1460","DOI":"10.1109\/LGRS.2013.2295326","article-title":"A Fast BP Algorithm With Wavenumber Spectrum Fusion for High-Resolution Spotlight SAR Imaging","volume":"11","author":"Zhang","year":"2014","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"786","DOI":"10.1109\/36.298008","article-title":"Precision SAR processing using chirp scaling","volume":"32","author":"Raney","year":"1994","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_31","unstructured":"Duan, S., and Li, J. (September, January 30). High Squint SAR Processing Using Modified Extended Chirp Scaling. Proceedings of the First International Conference on Innovative Computing, Information and Control (ICICIC\u201906), Beijing, China."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1123","DOI":"10.1109\/36.536528","article-title":"Extended chirp scaling algorithm for air- and spaceborne SAR data processing in stripmap and ScanSAR imaging modes","volume":"34","author":"Moreira","year":"1996","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Hui, K., Jie, C., and Wei, Y. (2015, January 1\u20134). A modified chirp-scaling algorithm for spaceborne squinted sliding spotlight SAR data processing. Proceedings of the 2015 IEEE 5th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR), Singapore.","DOI":"10.1109\/APSAR.2015.7306248"},{"key":"ref_34","first-page":"511","article-title":"Optimizing the minimum cost flow algorithm for the phase unwrapping process in sar radar. Bulletin of the Polish Academy of Sciences","volume":"62","author":"Dudczyk","year":"2014","journal-title":"Tech. Sci."},{"key":"ref_35","first-page":"5204617","article-title":"Quasi-Orthogonal Waveforms for Ambiguity Suppression in Spaceborne Quad-Pol SAR","volume":"60","author":"Jin","year":"2021","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_36","first-page":"5202613","article-title":"Ambiguity Suppression of Cross-Pol Signals by DPCA With DBF Reflector for Hybrid\/\u00b1\u03c0\/4 Quad-Pol SAR","volume":"60","author":"Zhang","year":"2021","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Zhao, P., Deng, Y., Wang, W., Zhang, Y., and Wang, R. (2021). Ambiguity Suppression Based on Joint Optimization for Multichannel Hybrid and \u00b1\u03c0\/4 Quad-Pol SAR Systems. Remote Sens., 13.","DOI":"10.3390\/rs13101907"},{"key":"ref_38","unstructured":"Ulaby, F.T., and Dobson, M.C. (1989). Handbook of Radar Scattering Statistics for Terrain, Artech House."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1109\/36.823926","article-title":"The \u201cMyth\u201d of the minimum SAR antenna area constraint","volume":"38","author":"Freeman","year":"2000","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Zhang, Y., Zhang, Y., Deng, Y., Chang, S., Liu, D., and Wang, R. (2020, January 21\u201325). A Quad-Pol SAR Imaging Mode with Sound Azimuth Ambiguity. Proceedings of the 2020 IEEE Radar Conference (RadarConf20), Florence, Italy.","DOI":"10.1109\/RadarConf2043947.2020.9266465"},{"key":"ref_41","unstructured":"Van Trees, H.L. (2004). Optimum Array Processing, John Wiley & Sons."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/1\/155\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:56:08Z","timestamp":1760169368000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/1\/155"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,12,30]]},"references-count":41,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2022,1]]}},"alternative-id":["rs14010155"],"URL":"https:\/\/doi.org\/10.3390\/rs14010155","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2021,12,30]]}}}