{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T14:46:22Z","timestamp":1778251582755,"version":"3.51.4"},"reference-count":35,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2021,10,1]],"date-time":"2021-10-01T00:00:00Z","timestamp":1633046400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>In a low-angle tracking situation, estimating the elevation angle is challenging due to the entrance of the multipath signals in the antenna\u2019s main lobe. In this article, we propose two methods based on the extended Kalman filter (EKF) and frequency diversity (FD) process to estimate the elevation angle of a low-angle isolated target. In the first case, a simple weighting of the per-frequency estimates is obtained (termed WFD). Differently, in the second case, a matrix-based elaboration of the per-frequency estimates is proposed (termed MFD). The proposed methods are completely independent of prior knowledge of geometrical information and the physical parameters. The simulation results show that both methods have excellent performance and guarantee accurate elevation angle estimation in different multipath environments and even in very-low SNR conditions. Hence, they are both suitable for low-peak-power radars.<\/jats:p>","DOI":"10.3390\/rs13193938","type":"journal-article","created":{"date-parts":[[2021,10,8]],"date-time":"2021-10-08T21:26:20Z","timestamp":1633728380000},"page":"3938","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Tracking a Low-Angle Isolated Target via an Elevation-Angle Estimation Algorithm Based on Extended Kalman Filter with an Array Antenna"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2102-9801","authenticated-orcid":false,"given":"Hossein","family":"Darvishi","sequence":"first","affiliation":[{"name":"Department of Electronic Systems, Norwegian University of Science and Technology, 7491 Trondheim, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohammad Ali","family":"Sebt","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, K. N. Toosi University of Technology, Tehran 15875-4416, Iran"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6230-2958","authenticated-orcid":false,"given":"Domenico","family":"Ciuonzo","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering and Information Technologies (DIETI), University of Naples \u201cFederico II\u201d, 80125 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pierluigi","family":"Salvo Rossi","sequence":"additional","affiliation":[{"name":"Department of Electronic Systems, Norwegian University of Science and Technology, 7491 Trondheim, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1109\/TAES.1974.307892","article-title":"Low-angle radar tracking in the presence of multipath","volume":"AES-10","author":"White","year":"1974","journal-title":"IEEE Trans. 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