{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T15:17:46Z","timestamp":1780413466521,"version":"3.54.1"},"reference-count":41,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2022,11,26]],"date-time":"2022-11-26T00:00:00Z","timestamp":1669420800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Austrian defense research programme FORTE of the Federal Ministry of Agriculture, Regions and Tourism (BMLRT)","award":["873433"],"award-info":[{"award-number":["873433"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Rapid and accurate reconnaissance in the event of radiological and nuclear (RN) incidents or attacks is vital to launch an appropriate response. This need is made stronger by the increasing threat of RN attacks on soft targets and critical infrastructure in densely populated areas. In such an event, even small radioactive sources can cause major disruption to the general population. In this work, we present a real-time radiological source localization method based on an optimization problem considering a background and radiation model. Supported by extensive real-world experiments, we show that an airborne system using this method is capable for reliably locating category 3\u20134 radioactive sources according to IAEA safety standards in real time from altitudes up to 150 m. A sensor bundle including a LiDAR sensor, a Gamma probe as well as a communication module was mounted on a UAV that served as a carrier platform. The method was evaluated on a comprehensive set of test flights, including 28 flight scenarios over 316 min using three different radiation sources. All additional gamma sources were correctly detected, multiple sources were detected if they were sufficiently separated from each other, with the distance between the true source position and the estimated source averaging 17.1 m. We also discuss the limitations of the system in terms of detection limit and source separation.<\/jats:p>","DOI":"10.3390\/s22239198","type":"journal-article","created":{"date-parts":[[2022,11,28]],"date-time":"2022-11-28T08:13:09Z","timestamp":1669623189000},"page":"9198","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Real-Time Gamma Radioactive Source Localization by Data Fusion of 3D-LiDAR Terrain Scan and Radiation Data from Semi-Autonomous UAV Flights"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3915-204X","authenticated-orcid":false,"given":"Stephan","family":"Schraml","sequence":"first","affiliation":[{"name":"AIT Austrian Institute of Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1640-5614","authenticated-orcid":false,"given":"Michael","family":"Hubner","sequence":"additional","affiliation":[{"name":"AIT Austrian Institute of Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4708-9455","authenticated-orcid":false,"given":"Philip","family":"Taupe","sequence":"additional","affiliation":[{"name":"AIT Austrian Institute of Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Hofst\u00e4tter","sequence":"additional","affiliation":[{"name":"AIT Austrian Institute of Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0071-6642","authenticated-orcid":false,"given":"Philipp","family":"Amon","sequence":"additional","affiliation":[{"name":"RIEGL Laser Measurement Systems GmbH, Riedenburgstr. 48, 3580 Horn, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dieter","family":"Rothbacher","sequence":"additional","affiliation":[{"name":"CBRN Protection GmbH, 1200 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"5953","DOI":"10.1080\/01431161.2016.1252474","article-title":"Airborne radiation mapping: Overview and application of current and future aerial systems","volume":"37","author":"Connor","year":"2016","journal-title":"Int. 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