{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:11:51Z","timestamp":1760148711739,"version":"build-2065373602"},"reference-count":21,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2023,5,30]],"date-time":"2023-05-30T00:00:00Z","timestamp":1685404800000},"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":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"],"award-info":[{"award-number":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Postdoctoral Innovation Talent Support Program","award":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"],"award-info":[{"award-number":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"]}]},{"name":"National Defense Foundation of China","award":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"],"award-info":[{"award-number":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"]}]},{"name":"China Postdoctoral Foundation","award":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"],"award-info":[{"award-number":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"]}]},{"name":"National Science Fund for Distin-guished Young Scholars","award":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"],"award-info":[{"award-number":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"]}]},{"name":"Fund for Foreign Scholars in University Research and Teaching Programs","award":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"],"award-info":[{"award-number":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"]}]},{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities","doi-asserted-by":"publisher","award":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"],"award-info":[{"award-number":["61901344","BX20180239","80913010102","2019M653562","61525105","B18039","QTZX22153"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Micro-Doppler (m-D) analysis is the most effective mechanism for detecting rotating targets or components; however, it fails when the target rotation plane is perpendicular to the radar line of sight (LOS). The vortex electromagnetic wave (VEMW) provides a unconventional structure of wavefront phase modulation on the cross-plane of the radar LOS, on which the radial m-D vanishes while the rotational Doppler (RD) appears. In the absence of the position of rotation center, this paper focuses on the micromotion parameters estimation based on RD effect for rotating target, and then proposes an estimation procedure, referred to as the two-step method. The micromotion parameters of the rotating target include the rotation attitude, the rotation radius and the position of the rotation center while the latter is coupled to the former two. Firstly, the micromotion parameters are roughly estimated based on the RD curve parameters obtained from the time-frequency (TF) spectrum of the received signal. Secondly, the maximum likelihood estimation (MLE) is used to accurately estimate the micromotion parameters. In addition, the Cram\u00e9r\u2013Rao bound (CRB) of parameter estimation is derived. The simulation studies the influencing factors of estimation performance and verifies that the proposed estimation method can provide excellent estimation accuracy of the micromotion parameters.<\/jats:p>","DOI":"10.3390\/rs15112847","type":"journal-article","created":{"date-parts":[[2023,5,31]],"date-time":"2023-05-31T02:27:30Z","timestamp":1685500050000},"page":"2847","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Micromotion Feature Extraction with VEMW Radar Based on Rotational Doppler Effect"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6519-1114","authenticated-orcid":false,"given":"Kun","family":"Lv","sequence":"first","affiliation":[{"name":"National Key Laboratory of Radar Signal Processing, Xidian University, Xi\u2019an 710071, China"}]},{"given":"Hui","family":"Ma","sequence":"additional","affiliation":[{"name":"National Key Laboratory of Radar Signal Processing, Xidian University, Xi\u2019an 710071, China"}]},{"given":"Xinrui","family":"Jiang","sequence":"additional","affiliation":[{"name":"Science and Technology on Millimeter-Wave Laboratory, Beijing Institute of Remote-Sensing Equipment, Beijing 100854, China"}]},{"given":"Jian","family":"Bai","sequence":"additional","affiliation":[{"name":"Science and Technology on Millimeter-Wave Laboratory, Beijing Institute of Remote-Sensing Equipment, Beijing 100854, China"}]},{"given":"Hongwei","family":"Liu","sequence":"additional","affiliation":[{"name":"National Key Laboratory of Radar Signal Processing, Xidian University, Xi\u2019an 710071, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"8185","DOI":"10.1103\/PhysRevA.45.8185","article-title":"Orbital angular momentum of light and the transformation of Laguerre\u2013Gaussian laser modes","volume":"45","author":"Allen","year":"1992","journal-title":"Phys. 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