{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,18]],"date-time":"2026-06-18T17:29:45Z","timestamp":1781803785036,"version":"3.54.5"},"reference-count":33,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2021,9,3]],"date-time":"2021-09-03T00:00:00Z","timestamp":1630627200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000780","name":"European Commission","doi-asserted-by":"publisher","award":["H2020-MG-2017-769066-RESIST"],"award-info":[{"award-number":["H2020-MG-2017-769066-RESIST"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000780","name":"European Commission","doi-asserted-by":"publisher","award":["H2020-ICT-2019-2-871542-PILOTING"],"award-info":[{"award-number":["H2020-ICT-2019-2-871542-PILOTING"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100010198","name":"Ministerio de Econom\u00eda, Industria y Competitividad, Gobierno de Espa\u00f1a","doi-asserted-by":"publisher","award":["RTI2018-102224-B-I00-ARTIC"],"award-info":[{"award-number":["RTI2018-102224-B-I00-ARTIC"]}],"id":[{"id":"10.13039\/501100010198","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper presents a localization system for Unmanned Aerial Vehicles (UAVs) especially designed to be used in infrastructure inspection, where the UAVs have to fly in challenging conditions, such as relatively high altitude (e.g., 15 m), eventually with poor or absent GNSS (Global Navigation Satellite System) signal reception, or the need for a BVLOS (Beyond Visual Line of Sight) operation in some periods. In addition, these infrastructure inspection applications impose the following requirements for the localization system: defect traceability, accuracy, reliability, and fault tolerance. Our system proposes a lightweight solution combining multiple stereo cameras with a robotic total station to comply with these requirements, providing full-state estimation (i.e., position, orientation, and linear and angular velocities) in a fixed and time-persistent reference frame. Moreover, the system can align and fuse all sensor measurements in real-time at high frequency. We have integrated this localization system in our aerial platform, and we have tested its performance for inspection in a real-world viaduct scenario, where the UAV has to operate with poor or absent GNSS signal at high altitude.<\/jats:p>","DOI":"10.3390\/s21175937","type":"journal-article","created":{"date-parts":[[2021,9,6]],"date-time":"2021-09-06T13:18:26Z","timestamp":1630934306000},"page":"5937","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Localization System for Lightweight Unmanned Aerial Vehicles in Inspection Tasks"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6466-8227","authenticated-orcid":false,"given":"Diego","family":"Benjumea","sequence":"first","affiliation":[{"name":"GRVC Robotics Laboratory, University of Seville, 41004 Sevilla, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4307-0995","authenticated-orcid":false,"given":"Alfonso","family":"Alc\u00e1ntara","sequence":"additional","affiliation":[{"name":"GRVC Robotics Laboratory, University of Seville, 41004 Sevilla, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9634-5449","authenticated-orcid":false,"given":"Agustin","family":"Ramos","sequence":"additional","affiliation":[{"name":"GRVC Robotics Laboratory, University of Seville, 41004 Sevilla, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0155-7671","authenticated-orcid":false,"given":"Arturo","family":"Torres-Gonzalez","sequence":"additional","affiliation":[{"name":"GRVC Robotics Laboratory, University of Seville, 41004 Sevilla, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9791-4148","authenticated-orcid":false,"given":"Pedro","family":"S\u00e1nchez-Cuevas","sequence":"additional","affiliation":[{"name":"GRVC Robotics Laboratory, University of Seville, 41004 Sevilla, Spain"},{"name":"Space Robotics Research Group, SnT\u2014University of Luxembourg, 1855 Luxembourg, Luxembourg"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7534-0187","authenticated-orcid":false,"given":"Jesus","family":"Capitan","sequence":"additional","affiliation":[{"name":"GRVC Robotics Laboratory, University of Seville, 41004 Sevilla, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1571-173X","authenticated-orcid":false,"given":"Guillermo","family":"Heredia","sequence":"additional","affiliation":[{"name":"GRVC Robotics Laboratory, University of Seville, 41004 Sevilla, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2155-2472","authenticated-orcid":false,"given":"Anibal","family":"Ollero","sequence":"additional","affiliation":[{"name":"GRVC Robotics Laboratory, University of Seville, 41004 Sevilla, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Valavanis, K.P., and Vachtsevanos, G.J. 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