{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,22]],"date-time":"2026-01-22T06:04:56Z","timestamp":1769061896265,"version":"3.49.0"},"reference-count":15,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2019,12,25]],"date-time":"2019-12-25T00:00:00Z","timestamp":1577232000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Information"],"abstract":"<jats:p>At present, there are two main problems in the commonly used radar emitter identification methods. First, when the distribution of training data and testing data is quite different, the identification accuracy is low. Second, the traditional identification methods usually include an offline training stage and online identifying stage, which cannot achieve the real-time identification of the radar emitter. Aimed at the above problems, this paper proposes a radar emitter identification method based on transfer learning and online learning. First, for the case where the target domain contains only a small number of labeled samples, the TrAdaBoost method is used as the basic learning framework to train a support vector machine, which can obtain useful knowledge from the source domain to aid in the identification of the target domain. Then, for the case where the target domain does not contain labeled samples, the Expectation-Maximization algorithm is used to filter the unlabeled samples in the target domain to generate the available training data. Finally, to make the identification quickly and accurately, we propose a radar emitter identification method, based on online learning to ensure real-time updating of the model. Simulation experiments show that the proposed method, based on transfer learning and online learning, has higher identification accuracy and good timeliness.<\/jats:p>","DOI":"10.3390\/info11010015","type":"journal-article","created":{"date-parts":[[2019,12,25]],"date-time":"2019-12-25T11:07:48Z","timestamp":1577272068000},"page":"15","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Radar Emitter Identification under Transfer Learning and Online Learning"],"prefix":"10.3390","volume":"11","author":[{"given":"Yuntian","family":"Feng","sequence":"first","affiliation":[{"name":"State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System, Luoyang 471003, China"}]},{"given":"Yanjie","family":"Cheng","sequence":"additional","affiliation":[{"name":"State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System, Luoyang 471003, China"}]},{"given":"Guoliang","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System, Luoyang 471003, China"}]},{"given":"Xiong","family":"Xu","sequence":"additional","affiliation":[{"name":"State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System, Luoyang 471003, China"}]},{"given":"Hui","family":"Han","sequence":"additional","affiliation":[{"name":"State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System, Luoyang 471003, China"}]},{"given":"Ruowu","family":"Wu","sequence":"additional","affiliation":[{"name":"State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System, Luoyang 471003, China"}]}],"member":"1968","published-online":{"date-parts":[[2019,12,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"280","DOI":"10.1017\/S0001924000087108","article-title":"ELINT: The Interception and Analysis of Radar Signals R.G. 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