{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:28:24Z","timestamp":1760149704207,"version":"build-2065373602"},"reference-count":34,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2023,8,31]],"date-time":"2023-08-31T00:00:00Z","timestamp":1693440000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the National Natural Science Foundation of China","award":["61671469","2022CFB901"],"award-info":[{"award-number":["61671469","2022CFB901"]}]},{"name":"Hubei Natural Science Foundation Youth Program","award":["61671469","2022CFB901"],"award-info":[{"award-number":["61671469","2022CFB901"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Spectrum aliasing occurs in signal echoes when the sampling frequency does not comply with the Nyquist Sampling Theorem. In this scenario, the extraction of micro-motion parameters becomes challenging. This paper proposes a spectral de-aliasing method for micro-motion signals based on a complex-valued U-Net network. Zero interpolation is employed to insert zeros into the echo, effectively increasing the sampling frequency. After zero interpolation, the micro-motion signal contains both real micro-motion signal frequency components and new frequency components. Short-Time Fourier Transform (STFT) is then applied to transform the zero-interpolated echo from the time domain to the time\u2013frequency domain. Furthermore, a complex-valued U-Net training model is utilized to eliminate redundant frequency components generated by zero interpolation, thereby achieving the frequency reconstruction of micro-motion signal echoes. Finally, the training models are employed to process the measured data. The theoretical analysis, simulations, and experimental results demonstrate that this method is robust and feasible, and is capable of addressing the problem of micro-motion signal echo spectrum aliasing in narrowband radar.<\/jats:p>","DOI":"10.3390\/rs15174299","type":"journal-article","created":{"date-parts":[[2023,8,31]],"date-time":"2023-08-31T11:45:51Z","timestamp":1693482351000},"page":"4299","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Spectral De-Aliasing Method of Micro-Motion Signals Based on a Complex-Valued U-Net Network"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6089-5200","authenticated-orcid":false,"given":"Ming","family":"Long","sequence":"first","affiliation":[{"name":"Airforce Early Warning Academy, Wuhan 430019, China"}]},{"given":"Jun","family":"Yang","sequence":"additional","affiliation":[{"name":"Airforce Early Warning Academy, Wuhan 430019, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3416-8197","authenticated-orcid":false,"given":"Saiqiang","family":"Xia","sequence":"additional","affiliation":[{"name":"Airforce Early Warning Academy, Wuhan 430019, China"}]},{"given":"Mingjiu","family":"Lv","sequence":"additional","affiliation":[{"name":"Airforce Early Warning Academy, Wuhan 430019, China"}]},{"given":"Bolin","family":"Cheng","sequence":"additional","affiliation":[{"name":"Airforce Early Warning Academy, Wuhan 430019, China"}]},{"given":"Wenfeng","family":"Chen","sequence":"additional","affiliation":[{"name":"Airforce Early Warning Academy, Wuhan 430019, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,8,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1049\/ip-rsn:20030743","article-title":"Analysis of Micro-Doppler Signatures","volume":"150","author":"Chen","year":"2003","journal-title":"IEE Proc. 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