{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T05:57:23Z","timestamp":1761631043445,"version":"build-2065373602"},"reference-count":24,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2023,9,5]],"date-time":"2023-09-05T00:00:00Z","timestamp":1693872000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key R&amp;D Program of China","award":["2022YFB3902400","2018YFB2202500","62035014","62201591","61921001","61971427"],"award-info":[{"award-number":["2022YFB3902400","2018YFB2202500","62035014","62201591","61921001","61971427"]}]},{"name":"National Natural Science Foundation of China","award":["2022YFB3902400","2018YFB2202500","62035014","62201591","61921001","61971427"],"award-info":[{"award-number":["2022YFB3902400","2018YFB2202500","62035014","62201591","61921001","61971427"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>In recent years, terahertz (THz) radar has been widely researched for its high-resolution imaging. However, the traditional inverse synthetic aperture radar (ISAR) imaging algorithms in the microwave band perform unsatisfactorily in the THz band. Firstly, due to THz radar\u2019s large bandwidth and short wavelength, the rotation of the target will result in serious space-varying(SV) range migration and space-varying phase error. Furthermore, it is challenging to accurately estimate the rotational velocity and compensate for phase errors in the presence of severe range migration effects. Therefore, in this paper, a high-precision THz-ISAR imaging algorithm is proposed. The algorithm includes the following step: First, the SV first-order range migration(FRM) is corrected using keystone transform (KT); then, the minimum entropy based on modified newton (ME-MN) is used to estimate the rotational velocity roughly, and the remaining SV second-order range migration(SRM) is corrected to obtain the range profile with the envelope alignment. Finally, the echo after the envelope alignment is processed for the second time based on ME-MN. The target rotation velocity is accurately estimated, and the phase error is compensated to obtain a well-focused imaging result. The validity of the proposed method is verified by numerical simulation and electromagnetic calculation data.<\/jats:p>","DOI":"10.3390\/rs15184371","type":"journal-article","created":{"date-parts":[[2023,9,5]],"date-time":"2023-09-05T10:26:43Z","timestamp":1693909603000},"page":"4371","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["High Precision Motion Compensation THz-ISAR Imaging Algorithm Based on KT and ME-MN"],"prefix":"10.3390","volume":"15","author":[{"given":"Wei","family":"Liu","sequence":"first","affiliation":[{"name":"College of Electronic Science, National University of Defense Technology, Changsha 410073, China"}]},{"given":"Hongqiang","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Electronic Science, National University of Defense Technology, Changsha 410073, China"}]},{"given":"Qi","family":"Yang","sequence":"additional","affiliation":[{"name":"College of Electronic Science, National University of Defense Technology, Changsha 410073, China"}]},{"given":"Bin","family":"Deng","sequence":"additional","affiliation":[{"name":"College of Electronic Science, National University of Defense Technology, Changsha 410073, China"}]},{"given":"Lei","family":"Fan","sequence":"additional","affiliation":[{"name":"College of Electronic Science, National University of Defense Technology, Changsha 410073, China"}]},{"given":"Jun","family":"Yi","sequence":"additional","affiliation":[{"name":"College of Electronic Science, National University of Defense Technology, Changsha 410073, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,9,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"5214621","DOI":"10.1109\/TGRS.2021.3113007","article-title":"Ultrawideband ISAR Imaging of Maneuvering Targets With Joint High-Order Motion Compensation and Azimuth Scaling","volume":"60","author":"Shao","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1109\/TAES.1980.308875","article-title":"Range-Doppler Imaging of Rotating Objects","volume":"AES16","author":"Walker","year":"1980","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1109\/TGRS.2017.2733579","article-title":"A High-Precision Method of Phase-Derived Velocity Measurement and Its Application in Motion Compensation of ISAR Imaging","volume":"56","author":"Fan","year":"2018","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1109\/TMTT.2018.2874666","article-title":"A High-Resolution 220-GHz Ultra-Wideband Fully Integrated ISAR Imaging System","volume":"67","author":"Mostajeran","year":"2019","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Zhang, Y., Yang, Q., Deng, B., Qin, Y., and Wang, H. (2019). Experimental Research on Interferometric Inverse Synthetic Aperture Radar Imaging with Multi-Channel Terahertz Radar System. Sensors, 19.","DOI":"10.3390\/s19102330"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"994","DOI":"10.1109\/22.3624","article-title":"Design and Performance of a 215-Ghz Pulsed Radar System","volume":"36","author":"McIntosh","year":"1988","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1109\/TTHZ.2011.2159556","article-title":"THz Imaging Radar for Standoff Personnel Screening","volume":"1","author":"Cooper","year":"2011","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2241","DOI":"10.1109\/TGRS.2012.2209892","article-title":"Three-dimensional image reconstruction of targets under the illumination of terahertz gaussian beam-theory and experiment","volume":"51","author":"Gu","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1109\/TTHZ.2017.2781462","article-title":"Wide-Angle CSAR Imaging Based on the Adaptive Subaperture Partition Method in the Terahertz Band","volume":"8","author":"Liu","year":"2018","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Kim, S.-H., Fan, R., and Dominski, F. (2018, January 23\u201327). ViSAR: A 235 GHz Radar for Airborne Applications. [\u201cAdvanced Concepts and Technology, Raytheon, Space and Airborne Systems, El Segundo, CA\u201d]. Proceedings of the 2018 IEEE Radar Conference (RadarConf18), Oklahoma City, OK, USA.","DOI":"10.1109\/RADAR.2018.8378797"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1558","DOI":"10.1109\/TAES.2021.3126375","article-title":"Space-Based Sub-THz ISAR for Space Situational Awareness\u2014Concept and Design","volume":"58","author":"Marchetti","year":"2022","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"4409","DOI":"10.1109\/TAES.2022.3160985","article-title":"Space-Based Sub-THz ISAR for Space Situational Awareness\u2014Laboratory Validation","volume":"58","author":"Marchetti","year":"2022","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Marchetti, E., Stove, A., Hoare, E., Cherniakov, M., and Gashinova, M. (2022, January 5\u20137). Images of satellite elements with a space-borne Sub-THz ISAR system. Proceedings of the 2021 18th European Radar Conference (EuRAD), London, UK.","DOI":"10.23919\/EuRAD50154.2022.9784477"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1109\/TAES.1980.308873","article-title":"Target-Motion-Induced Radar Imaging","volume":"AES16","author":"Chen","year":"1980","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"204","DOI":"10.1109\/LGRS.2008.2010562","article-title":"Robust ISAR Range Alignment via Minimizing the Entropy of the Average Range Profile","volume":"6","author":"Zhu","year":"2009","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1561","DOI":"10.1109\/83.469937","article-title":"Translational motion compensation in ISAR image processing","volume":"4","author":"Wu","year":"1995","journal-title":"IEEE Trans. Image Process."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"680","DOI":"10.9766\/KIMST.2014.17.5.680","article-title":"Improvement of ISAR Autofocusing Performance Based on PGA","volume":"17","author":"Kim","year":"2014","journal-title":"J. Korea Inst. Mil. Sci. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1240","DOI":"10.1109\/7.805442","article-title":"Autofocusing of ISAR images based on entropy minimization","volume":"35","author":"Xi","year":"1999","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1185","DOI":"10.1109\/7.532282","article-title":"Autofocusing of inverse synthetic aperture radar images using contrastoptimization","volume":"32","author":"Berizzi","year":"1996","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"966","DOI":"10.1109\/TGRS.2012.2204889","article-title":"Robust ground moving-target imaging using deramp-keystone processing(Article)","volume":"51","author":"Sun","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2095","DOI":"10.1109\/TGRS.2020.2994337","article-title":"Integration of Rotation Estimation and High-Order Compensation for Ultrahigh-Resolution Microwave Photonic ISAR Imagery","volume":"59","author":"Yang","year":"2021","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Wang, H., Yang, Q., Wang, H., and Deng, B. (2022). Autofocusing of Maneuvering Targets in Terahertz Inverse Synthetic Aperture Radar Imaging Based on Damped Newton Method. Sensors, 22.","DOI":"10.3390\/s22186883"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3721","DOI":"10.1109\/TGRS.2017.2678763","article-title":"A Modified Equivalent Range Model and Wavenumber-Domain Imaging Approach for High-Resolution-High-Squint SAR with Curved Trajectory","volume":"55","author":"Li","year":"2017","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1355","DOI":"10.1109\/TAES.2017.2785560","article-title":"Fast ISAR Cross-range Scaling Using Modified Newton Method","volume":"54","author":"Zhang","year":"2018","journal-title":"IEEE Trans. Aerosp. Electron. Syst."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/18\/4371\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T20:47:01Z","timestamp":1760129221000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/18\/4371"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,9,5]]},"references-count":24,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2023,9]]}},"alternative-id":["rs15184371"],"URL":"https:\/\/doi.org\/10.3390\/rs15184371","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2023,9,5]]}}}