{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,13]],"date-time":"2026-03-13T15:03:57Z","timestamp":1773414237087,"version":"3.50.1"},"reference-count":45,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2021,5,15]],"date-time":"2021-05-15T00:00:00Z","timestamp":1621036800000},"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>The use and research of Unmanned Aerial Vehicle (UAV) have been increasing over the years due to the applicability in several operations such as search and rescue, delivery, surveillance, and others. Considering the increased presence of these vehicles in the airspace, it becomes necessary to reflect on the safety issues or failures that the UAVs may have and the appropriate action. Moreover, in many missions, the vehicle will not return to its original location. If it fails to arrive at the landing spot, it needs to have the onboard capability to estimate the best area to safely land. This paper addresses the scenario of detecting a safe landing spot during operation. The algorithm classifies the incoming Light Detection and Ranging (LiDAR) data and store the location of suitable areas. The developed method analyses geometric features on point cloud data and detects potential right spots. The algorithm uses the Principal Component Analysis (PCA) to find planes in point cloud clusters. The areas that have a slope less than a threshold are considered potential landing spots. These spots are evaluated regarding ground and vehicle conditions such as the distance to the UAV, the presence of obstacles, the area\u2019s roughness, and the spot\u2019s slope. Finally, the output of the algorithm is the optimum spot to land and can vary during operation. The proposed approach evaluates the algorithm in simulated scenarios and an experimental dataset presenting suitability to be applied in real-time operations.<\/jats:p>","DOI":"10.3390\/rs13101930","type":"journal-article","created":{"date-parts":[[2021,5,17]],"date-time":"2021-05-17T02:31:34Z","timestamp":1621218694000},"page":"1930","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Emergency Landing Spot Detection Algorithm for Unmanned Aerial Vehicles"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6496-232X","authenticated-orcid":false,"given":"Gabriel","family":"Loureiro","sequence":"first","affiliation":[{"name":"ISEP-School of Engineering, Electrical Engineering Department, 4200-072 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5734-075X","authenticated-orcid":false,"given":"Andr\u00e9","family":"Dias","sequence":"additional","affiliation":[{"name":"ISEP-School of Engineering, Electrical Engineering Department, 4200-072 Porto, Portugal"},{"name":"INESC Technology and Science, Centre for Robotics and Autonomous Systems, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3195-5638","authenticated-orcid":false,"given":"Alfredo","family":"Martins","sequence":"additional","affiliation":[{"name":"ISEP-School of Engineering, Electrical Engineering Department, 4200-072 Porto, Portugal"},{"name":"INESC Technology and Science, Centre for Robotics and Autonomous Systems, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5844-5393","authenticated-orcid":false,"given":"Jos\u00e9","family":"Almeida","sequence":"additional","affiliation":[{"name":"ISEP-School of Engineering, Electrical Engineering Department, 4200-072 Porto, Portugal"},{"name":"INESC Technology and Science, Centre for Robotics and Autonomous Systems, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,5,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"319","DOI":"10.14429\/dsj.65.8631","article-title":"Unmanned Aerial Vehicle Domain: Areas of Research","volume":"65","author":"Demir","year":"2015","journal-title":"Def. 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