{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,9]],"date-time":"2025-12-09T08:27:33Z","timestamp":1765268853603,"version":"build-2065373602"},"reference-count":42,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2022,6,21]],"date-time":"2022-06-21T00:00:00Z","timestamp":1655769600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Engineering Research Center of Mobile Communications, Ministry of Education","award":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"],"award-info":[{"award-number":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"]}]},{"name":"Natural Science Foundation of Chongqing, China","award":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"],"award-info":[{"award-number":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"]}]},{"name":"Opening Project of the Guangxi Wireless Broadband Communication","award":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"],"award-info":[{"award-number":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"]}]},{"name":"Signal Processing Key Laboratory","award":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"],"award-info":[{"award-number":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"]}]},{"name":"National Natural Science Foundation of China","award":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"],"award-info":[{"award-number":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"]}]},{"name":"Key Project of the Application and Development of Chongqing","award":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"],"award-info":[{"award-number":["cqupt-mct-202103","cstc2021jcyj-bshX0085","GXKL06200214","GXKL06200205","61971075","62001062","U20A20157","cstc2019jscx-fxydX0049"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The synthetic aperture radar (SAR) images of a moving target may be out of focus, given the motions of a non-cooperative target. Doppler ambiguities, including the Doppler center blur and spectrum ambiguity, will easily appear due to the limitations of pulse repetition frequency, which causes difficulty in moving-target imaging. Therefore, a robust fast Doppler ambiguity approach for SAR imaging of a ground-based moving target using range azimuth joint processing (RAJP) is presented. Firstly, the use of RAJP, based on a two-dimensional cross-correlation function and linear range cell migration (LRCM) compensation function, is proposed to simultaneously obtain the first- and second-order phase parameters in the fast-time and azimuth-frequency domains. Then, a corresponding azimuth reference function is constructed to image the moving target. Additionally, a principal component analysis-based operation is introduced to solve the mismatch with the LRCM compensation function. The couplings between the range and azimuth and between the first- and second-order parameters can be simultaneously decoupled by the proposed RAJP operation, which simplifies the processing steps. The developed approach can simultaneously obtain the first- and second-order parameters in the fast-time and azimuth-frequency domains, which avoids the propagation error of parameter estimation caused by the stepwise processing operation. The proposed method is relatively fast, given the need for fewer processing steps. The presented approach is robust in terms of Doppler ambiguity and handles the blind speed sidelobe well. In this study, simulated and real data are processed to verify the proposed approach.<\/jats:p>","DOI":"10.3390\/rs14132965","type":"journal-article","created":{"date-parts":[[2022,6,22]],"date-time":"2022-06-22T04:12:01Z","timestamp":1655871121000},"page":"2965","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Fast Approach for SAR Imaging of Ground-Based Moving Targets Based on Range Azimuth Joint Processing"],"prefix":"10.3390","volume":"14","author":[{"given":"Yuxiang","family":"Shu","sequence":"first","affiliation":[{"name":"The 38th Research Institute of China Electronics Technology Group Corporation, Hefei 230088, China"}]},{"given":"Jun","family":"Wan","sequence":"additional","affiliation":[{"name":"School of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, China"},{"name":"Chongqing Key Laboratory of Space Information Network and Intelligent Information Fusion, Chongqing University, Chongqing 400044, China"}]},{"given":"Dong","family":"Li","sequence":"additional","affiliation":[{"name":"School of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, China"},{"name":"Chongqing Key Laboratory of Space Information Network and Intelligent Information Fusion, Chongqing University, Chongqing 400044, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2590-7704","authenticated-orcid":false,"given":"Zhanye","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, China"},{"name":"Chongqing Key Laboratory of Space Information Network and Intelligent Information Fusion, Chongqing University, Chongqing 400044, China"}]},{"given":"Hongqing","family":"Liu","sequence":"additional","affiliation":[{"name":"Chongqing Key Laboratory of Mobile Communications Technology, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,21]]},"reference":[{"key":"ref_1","unstructured":"Cumming, I.G., and Wong, F.H. (2005). Digital Processing of Synthetic Aperture Radar Data: Algorithm and Implementation, Artech House."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1109\/MGRS.2013.2248301","article-title":"A tutorial on synthetic aperture radar","volume":"1","author":"Moreira","year":"2013","journal-title":"IEEE Geosci. Remote Sens. Mag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1109\/TCI.2020.3047473","article-title":"Plug-and-play synthetic aperture radar image formation using deep priors","volume":"7","author":"Alver","year":"2021","journal-title":"IEEE Trans. Comput. Imag."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"6434","DOI":"10.1109\/TGRS.2020.2976864","article-title":"Signal modeling and analysis for elevation frequency scanning HRWS SAR","volume":"58","author":"Liu","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"868","DOI":"10.1109\/TCI.2020.2993170","article-title":"OSRanP: A novel way for radar imaging utilizing joint sparsity and low-rankness","volume":"6","author":"Pu","year":"2020","journal-title":"IEEE Trans. Comput. Imag."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1109\/TGRS.2019.2936246","article-title":"Focusing hypersonic vehicle-borne SAR data using radius\/angle algorithm","volume":"58","author":"Tang","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1774","DOI":"10.1109\/TGRS.2017.2768243","article-title":"GMTI and parameter estimation for MIMO SAR system via fast interferometry RPCA method","volume":"56","author":"Huang","year":"2018","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Wan, J., Chen, Z., Zhou, Y., Li, D., Huang, Y., and Zhang, L. (October, January 26). Ground moving target imaging based on MSOKT and KT for synthetic aperture radar. Proceedings of the 2020 IEEE International Geoscience and Remote Sensing Symposium, Virtual Symposium.","DOI":"10.1109\/IGARSS39084.2020.9324382"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1109\/TCI.2018.2855436","article-title":"Refocusing and motion parameter estimation for ground moving targets based on improved axis rotation-time reversal transform","volume":"4","author":"Huang","year":"2018","journal-title":"IEEE Trans. Comput. Imag."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"5015","DOI":"10.1109\/JSTARS.2015.2450019","article-title":"Simultaneous high-resolution wide-swath SAR imaging and ground moving target indication: Processing approaches and system concepts","volume":"8","author":"Baumgartner","year":"2015","journal-title":"IEEE J. Sel. Topics Appl. Earth Observ. Remote Sens."},{"key":"ref_11","first-page":"4012905","article-title":"Single range data-based clutter suppression method for multichannel SAR","volume":"19","author":"Chen","year":"2022","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1109\/LGRS.2017.2777494","article-title":"Moving target refocusing algorithm in 2-D wavenumber domain after BP integral","volume":"15","author":"Dong","year":"2018","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"528","DOI":"10.1049\/iet-spr.2018.5225","article-title":"Ground moving target focusing and motion parameter estimation method via MSOKT for synthetic aperture radar","volume":"13","author":"Wan","year":"2019","journal-title":"IET Signal Process."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"462","DOI":"10.1109\/TGRS.2010.2053848","article-title":"Ground moving targets imaging algorithm for synthetic aperture radar","volume":"49","author":"Zhu","year":"2011","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"966","DOI":"10.1109\/TGRS.2012.2204889","article-title":"Robust ground moving-target imaging using deramp-Keystone processing","volume":"51","author":"Sun","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"646","DOI":"10.1049\/iet-rsn.2016.0262","article-title":"Coherent method for ground-moving target indication and velocity estimation using Hough transform","volume":"11","author":"Oveis","year":"2017","journal-title":"IET Radar Sonar Navig."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1049\/iet-rsn:20080123","article-title":"Application of the radon transform to detect small-targets in sea clutter","volume":"3","author":"Moya","year":"2009","journal-title":"IET Radar Sonar Navig."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"885","DOI":"10.1007\/s11045-018-0588-y","article-title":"Improved axis rotation MTD algorithm and its analysis","volume":"30","author":"Rao","year":"2019","journal-title":"Multidim. Syst. Sign. Process."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"188","DOI":"10.1109\/7.745691","article-title":"SAR imaging of moving targets","volume":"35","author":"Perry","year":"1999","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1109\/LGRS.2006.882147","article-title":"A keystone transform without interpolation for SAR ground moving-target imaging","volume":"4","author":"Zhu","year":"2007","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"774","DOI":"10.1049\/cje.2016.06.009","article-title":"High accuracy velocity measurement based on keystone transform using entropy minimization","volume":"25","author":"Dai","year":"2016","journal-title":"Chin. J. Electron."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"902","DOI":"10.1049\/iet-rsn.2010.0304","article-title":"Imaging moving targets using the second-order keystone transform","volume":"5","author":"Kirkland","year":"2011","journal-title":"IET Radar Sonar Navig."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1049\/iet-rsn:20060040","article-title":"Approach for single channel SAR ground moving target imaging and motion parameter estimation","volume":"1","author":"Zhou","year":"2007","journal-title":"IET Radar Sonar Navig."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1109\/LGRS.2008.2000621","article-title":"Doppler keystone transform: An approach suitable for parallel implementation of SAR moving target imaging","volume":"5","author":"Li","year":"2008","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Wan, J., Tan, X., Chen, Z., Li, D., Liu, Q., Zhou, Y., and Zhang, L. (2021). Refocusing of ground moving targets with Doppler ambiguity using Keystone transform and modified second-order Keystone transform for synthetic aperture radar. Remote Sens., 13.","DOI":"10.3390\/rs13020177"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1109\/TGRS.2016.2606437","article-title":"An approach for refocusing of ground moving target without motion parameter estimation","volume":"55","author":"Huang","year":"2017","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1109\/TCI.2015.2510499","article-title":"Parameter estimation of ground moving targets based on SKT-DLVT processing","volume":"2","author":"Tian","year":"2016","journal-title":"IEEE Trans. Comput. Imag."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3412","DOI":"10.1109\/JSTARS.2019.2929655","article-title":"Coherent detection algorithm for radar maneuvering targets based on discrete polynomial-phase transform","volume":"12","author":"Pang","year":"2019","journal-title":"IEEE J. Sel. Topics Appl. Earth Observ. Remote Sens."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"939","DOI":"10.1109\/TSP.2013.2297682","article-title":"Maneuvering target detection via Radon-fractional Fourier transform-based long-time coherent integration","volume":"62","author":"Chen","year":"2014","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_30","first-page":"13","article-title":"Computational efficient refocusing and estimation method for radar moving target with unknown time information","volume":"2","author":"Li","year":"2016","journal-title":"IEEE Trans. Comput. Imag."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1306","DOI":"10.1109\/TAES.2017.2780658","article-title":"Polynomial radon-polynomial Fourier transform for near space hypersonic maneuvering target detection","volume":"54","author":"Wu","year":"2018","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TGRS.2022.3229086","article-title":"A modified keystone transform matched filtering method for space-moving target detection","volume":"60","author":"Zhan","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3718","DOI":"10.1109\/JSEN.2019.2960323","article-title":"Long-time coherent integration for maneuvering target detection based on ITRT-MRFT","volume":"20","author":"Lin","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1478","DOI":"10.1109\/JSEN.2018.2882198","article-title":"Radar detection and parameter estimation of high-speed target based on MART-LVT","volume":"19","author":"Li","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1109\/TAES.2007.4285361","article-title":"Efficient wideband signal parameter estimation using a Radon-ambiguity transform slice","volume":"43","author":"Sharif","year":"2007","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"920","DOI":"10.1109\/TGRS.2014.2330456","article-title":"Detection and imaging of ground moving targets with real SAR data","volume":"53","author":"Yang","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1109\/TCI.2016.2634421","article-title":"Imaging and parameter estimating for fast moving targets in airborne SAR","volume":"32","author":"Tan","year":"2017","journal-title":"IEEE Trans. Comput. Imag."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1186","DOI":"10.1109\/TAES.2011.5751251","article-title":"Radon-Fourier transform for radar target detection I: Generalized Doppler filter bank","volume":"47","author":"Xu","year":"2011","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"3909","DOI":"10.1109\/TSP.2016.2552511","article-title":"ISAR cross-range scaling using iterative processing via principal component analysis and bisection algorithm","volume":"64","author":"Kang","year":"2016","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"3525","DOI":"10.1109\/TAES.2012.6324734","article-title":"Radar detection of helicopters with application of CNEAN method","volume":"48","author":"Misiurewicz","year":"2012","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1671","DOI":"10.1049\/iet-rsn.2015.0653","article-title":"CLEAN-based coherent integration method for high-speed multi-targets detection","volume":"10","author":"Li","year":"2016","journal-title":"IET Radar Sonar Navig."},{"key":"ref_42","unstructured":"DiPietro, R.C. (1992, January 26\u201328). Extended factored space\u2013time processing for airborne radar systems. Proceedings of the 26th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, USA."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/13\/2965\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:36:38Z","timestamp":1760139398000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/13\/2965"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,6,21]]},"references-count":42,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2022,7]]}},"alternative-id":["rs14132965"],"URL":"https:\/\/doi.org\/10.3390\/rs14132965","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2022,6,21]]}}}