{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T11:14:16Z","timestamp":1762254856563,"version":"build-2065373602"},"reference-count":35,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2024,4,16]],"date-time":"2024-04-16T00:00:00Z","timestamp":1713225600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Nature Science Foundation of China","doi-asserted-by":"publisher","award":["62371468","2021MD703951","2021-JCJQ-QT-018"],"award-info":[{"award-number":["62371468","2021MD703951","2021-JCJQ-QT-018"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"publisher","award":["62371468","2021MD703951","2021-JCJQ-QT-018"],"award-info":[{"award-number":["62371468","2021MD703951","2021-JCJQ-QT-018"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Youth Talent Lifting Project of the China Association for Science and Technology","award":["62371468","2021MD703951","2021-JCJQ-QT-018"],"award-info":[{"award-number":["62371468","2021MD703951","2021-JCJQ-QT-018"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Multi-rotor aircraft have the advantages of a simple structure, low cost, and flexible operation in the unmanned aerial vehicle (UAV) family, and have developed rapidly in recent years. Radar surveillance and classification of the growing number of multi-rotor aircraft has become a challenging problem due to their low-slow-small (LSS) characteristics. Estimation of the blade number is an important step in distinguishing LSS targets. However, most of the current research on micro-motion parameters estimation has focused on the analysis of rotational frequency, length, and the initial phase of blades with a prior of blade number, affecting its ability to identify LSS targets. In this article, a micro-motion parameters estimation method for multi-rotor targets without a prior is proposed. On the basis of estimating the flashing frequency of the blades, a validation function is constructed through spectral analysis to judge the number of blades, and then the rotational frequency is estimated. The blade length is calculated by estimating the maximum Doppler shift. Moreover, the variational mode decomposition (VMD)-based atomic scaling orthogonal matching pursuit (AS-OMP) method is jointly applied to estimate the blade length when suffering from the low PRF and insufficient SNR conditions. Extensive experiments on the simulated and measured data demonstrate that the proposed method outperforms robust micro-motion parameter estimation capability in low PRF and insufficient SNR conditions compared to the traditional time-frequency analysis methods.<\/jats:p>","DOI":"10.3390\/rs16081409","type":"journal-article","created":{"date-parts":[[2024,4,17]],"date-time":"2024-04-17T07:54:36Z","timestamp":1713340476000},"page":"1409","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["A Micro-Motion Parameters Estimation Method for Multi-Rotor Targets without a Prior"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-2812-3777","authenticated-orcid":false,"given":"Jianfei","family":"Ren","sequence":"first","affiliation":[{"name":"Information and Navigation College, Air Force Engineering University, Xi\u2019an 710077, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4557-9581","authenticated-orcid":false,"given":"Jia","family":"Liang","sequence":"additional","affiliation":[{"name":"Information and Navigation College, Air Force Engineering University, Xi\u2019an 710077, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7439-3295","authenticated-orcid":false,"given":"Huan","family":"Wang","sequence":"additional","affiliation":[{"name":"Xi\u2019an Electronic Engineering Research Institute, Xi\u2019an 710100, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9383-3017","authenticated-orcid":false,"given":"Kai-ming","family":"Li","sequence":"additional","affiliation":[{"name":"Information and Navigation College, Air Force Engineering University, Xi\u2019an 710077, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1460-4289","authenticated-orcid":false,"given":"Ying","family":"Luo","sequence":"additional","affiliation":[{"name":"Information and Navigation College, Air Force Engineering University, Xi\u2019an 710077, China"}]},{"given":"Dongtao","family":"Zhao","sequence":"additional","affiliation":[{"name":"Chinese Flight Test Establishment, Xi\u2019an 710089, China"}]}],"member":"1968","published-online":{"date-parts":[[2024,4,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/j.isprsjprs.2014.02.013","article-title":"Unmanned aerial systems for photogrammetry and remote sensing: A review","volume":"92","author":"Colomina","year":"2014","journal-title":"ISPRS J. 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