{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,29]],"date-time":"2025-12-29T22:16:02Z","timestamp":1767046562697,"version":"build-2065373602"},"reference-count":27,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2023,7,23]],"date-time":"2023-07-23T00:00:00Z","timestamp":1690070400000},"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":["62171468"],"award-info":[{"award-number":["62171468"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The degree of freedom (DOF) is an important performance metric for evaluating the design of a sparse array structure. Designing novel sparse arrays with higher degrees of freedom, while ensuring that the array structure can be mathematically represented, is a crucial research direction in the field of direction of arrival (DOA) estimation. In this paper, we propose a novel L-shaped sparse sensor array by adjusting the physical placement of the sensors in the sparse array. The proposed L-shaped sparse array consists of two sets of three-level and single-element sparse arrays (TSESAs), which estimate the azimuth and elevation angles, respectively, through one-dimensional (1-D) spatial spectrum search. Each TSESA is composed of a uniform linear subarray and two sparse subarrays, with one single common element in the two sparse subarrays. Compared to existing L-shaped sparse arrays, the proposed array achieves higher degrees of freedom, up to 4Q1Q2+8Q1\u22125, when estimating DOA using the received signal covariance. To facilitate the correct matching of azimuth and elevation angles, the cross-covariance between the two TSESA arrays is utilized for estimation. By comparing and analyzing performance parameters with commonly used L-shaped and other sparse arrays, it is found that the proposed L-shaped TSESA has higher degrees of freedom and array aperture, leading to improved two-dimensional (2-D) DOA estimation results. Finally, simulation experiments validate the excellent performance of the L-shaped TSESA in 2-D DOA estimation.<\/jats:p>","DOI":"10.3390\/s23146625","type":"journal-article","created":{"date-parts":[[2023,7,24]],"date-time":"2023-07-24T03:03:25Z","timestamp":1690167805000},"page":"6625","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["An L-Shaped Three-Level and Single Common Element Sparse Sensor Array for 2-D DOA Estimation"],"prefix":"10.3390","volume":"23","author":[{"given":"Bo","family":"Du","sequence":"first","affiliation":[{"name":"Institute of Information Engineering, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"},{"name":"School of Cyber Science and Engineering, Zhengzhou University, Zhengzhou 450002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Weijia","family":"Cui","sequence":"additional","affiliation":[{"name":"Institute of Information Engineering, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bin","family":"Ba","sequence":"additional","affiliation":[{"name":"Institute of Information Engineering, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8630-9049","authenticated-orcid":false,"given":"Haiyun","family":"Xu","sequence":"additional","affiliation":[{"name":"Institute of Information Engineering, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wubin","family":"Gao","sequence":"additional","affiliation":[{"name":"Research Office, Information Center, Beijing 100000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"422","DOI":"10.1049\/rsn2.12350","article-title":"Direction of arrival estimation based on slope fitting of wideband array signal in fractional fourier transform domain","volume":"17","author":"Zhong","year":"2023","journal-title":"IET Radar Sonar Navig."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1627","DOI":"10.1049\/rsn2.12285","article-title":"Joint 2d-doa and polarization estimation for electromagnetic vector sensors array with compressive measurements","volume":"16","author":"Zhu","year":"2022","journal-title":"IET Radar Sonar Navig."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1141","DOI":"10.1049\/iet-com.2018.5798","article-title":"Two-dimensional doa estimation for multi-path environments by accurate separation of signals using k-medoids clustering","volume":"13","author":"Molaei","year":"2019","journal-title":"IET Commun."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1266","DOI":"10.1109\/LCOMM.2020.2979066","article-title":"Two-dimensional doa estimation via a novel sparse array consisting of coprime and nested subarrays","volume":"24","author":"Si","year":"2020","journal-title":"IEEE Commun. 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