{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:45:12Z","timestamp":1760233512365,"version":"build-2065373602"},"reference-count":25,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,1,11]],"date-time":"2021-01-11T00:00:00Z","timestamp":1610323200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003336","name":"Bulgarian National Science Fund","doi-asserted-by":"publisher","award":["DN 07\/1\/14.12.2016"],"award-info":[{"award-number":["DN 07\/1\/14.12.2016"]}],"id":[{"id":"10.13039\/501100003336","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The paper analyses the possibility of Forward Scatter Radar (FSR) systems to detect airplanes using cosmic emission from pulsars and planets (pulsar, Sun, Moon). A suboptimal multichannel algorithm for joint detection and evaluation of the parameters of the forward scattering signal created by an airplane (duration and velocity) is proposed, with preliminary compensation of the powerful direct signal emitted by cosmic sources (pulsar, Sun and Moon). The expressions for calculation of the Signal-to-Noise Ratio (SNR) at the input of the detector and the compensator are obtained. The detection characteristics are also obtained, and the requirements for the suppression coefficient of the compensator are evaluated. A methodology for calculating the maximum distance for detecting an aircraft using a described algorithm is proposed. The obtained results show that due to the Forward Scatter (FS) effect, there is the theoretical possibility to detect airplanes at close ranges by FSRs, which use very weak signals from cosmic sources.<\/jats:p>","DOI":"10.3390\/s21020465","type":"journal-article","created":{"date-parts":[[2021,1,11]],"date-time":"2021-01-11T11:36:11Z","timestamp":1610364971000},"page":"465","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["FSR Systems for Detection of Air Objects Using Cosmic Radio Emissions"],"prefix":"10.3390","volume":"21","author":[{"given":"Hristo","family":"Kabakchiev","sequence":"first","affiliation":[{"name":"Faculty of Mathematics and Informatics, Sofia University, 1164 Sofia, Bulgaria"}]},{"given":"Vera","family":"Behar","sequence":"additional","affiliation":[{"name":"Mathematical Methods for Sensor Data Processing Department, Institute of Information and Communication Technologies, 1113 Sofia, Bulgaria"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3113-1751","authenticated-orcid":false,"given":"Ivan","family":"Garvanov","sequence":"additional","affiliation":[{"name":"Information Systems and Technologies Department, University of Library Studies and Information Technologies, 1784 Sofia, Bulgaria"}]},{"given":"Dorina","family":"Kabakchieva","sequence":"additional","affiliation":[{"name":"Faculty of Applied Informatics and Statistics, University of National and World Economy, 1700 Sofia, Bulgaria"}]},{"given":"Avgust","family":"Kabakchiev","sequence":"additional","affiliation":[{"name":"BULATCA, 1540 Sofia, Bulgaria"}]},{"given":"Hermann","family":"Rohling","sequence":"additional","affiliation":[{"name":"Institute of Communications, Technical University Hamburg-Harburg, 21073 Hamburg, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1002\/j.2161-4296.1968.tb01586.x","article-title":"The Radio Sextant","volume":"15","author":"Frye","year":"1968","journal-title":"Navigation"},{"key":"ref_2","unstructured":"Nikolaev, A., and Percov, S. 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