{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,18]],"date-time":"2026-05-18T10:53:31Z","timestamp":1779101611041,"version":"3.51.4"},"reference-count":54,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2023,7,26]],"date-time":"2023-07-26T00:00:00Z","timestamp":1690329600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ag\u00eancia Nacional de Inova\u00e7\u00e3o","award":["CENTRO-01-0247-FEDER-045931"],"award-info":[{"award-number":["CENTRO-01-0247-FEDER-045931"]}]},{"name":"Ag\u00eancia Nacional de Inova\u00e7\u00e3o","award":["PRT\/BD\/153920\/2022"],"award-info":[{"award-number":["PRT\/BD\/153920\/2022"]}]},{"name":"Ag\u00eancia Nacional de Inova\u00e7\u00e3o","award":["2022.05726.CEECIND"],"award-info":[{"award-number":["2022.05726.CEECIND"]}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia (Portuguese Foundation for Science and Technology)","doi-asserted-by":"publisher","award":["CENTRO-01-0247-FEDER-045931"],"award-info":[{"award-number":["CENTRO-01-0247-FEDER-045931"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia (Portuguese Foundation for Science and Technology)","doi-asserted-by":"publisher","award":["PRT\/BD\/153920\/2022"],"award-info":[{"award-number":["PRT\/BD\/153920\/2022"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia (Portuguese Foundation for Science and Technology)","doi-asserted-by":"publisher","award":["2022.05726.CEECIND"],"award-info":[{"award-number":["2022.05726.CEECIND"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Scientific Employment Stimulus 5th Edition","doi-asserted-by":"publisher","award":["CENTRO-01-0247-FEDER-045931"],"award-info":[{"award-number":["CENTRO-01-0247-FEDER-045931"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Scientific Employment Stimulus 5th Edition","doi-asserted-by":"publisher","award":["PRT\/BD\/153920\/2022"],"award-info":[{"award-number":["PRT\/BD\/153920\/2022"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Scientific Employment Stimulus 5th Edition","doi-asserted-by":"publisher","award":["2022.05726.CEECIND"],"award-info":[{"award-number":["2022.05726.CEECIND"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Forestry operations have become of great importance for a sustainable environment in the past few decades due to the increasing toll induced by rural abandonment and climate change. Robotics presents a promising solution to this problem; however, gathering the necessary data for developing and testing algorithms can be challenging. This work proposes a portable multi-sensor apparatus to collect relevant data generated by several onboard sensors. The system incorporates Laser Imaging, Detection and Ranging (LiDAR), two stereo depth cameras and a dedicated inertial measurement unit (IMU) to obtain environmental data, which are coupled with an Android app that extracts Global Navigation Satellite System (GNSS) information from a cell phone. Acquired data can then be used for a myriad of perception-based applications, such as localization and mapping, flammable material identification, traversability analysis, path planning and\/or semantic segmentation toward (semi-)automated forestry actuation. The modular architecture proposed is built on Robot Operating System (ROS) and Docker to facilitate data collection and the upgradability of the system. We validate the apparatus\u2019 effectiveness in collecting datasets and its flexibility by carrying out a case study for Simultaneous Localization and Mapping (SLAM) in a challenging woodland environment, thus allowing us to compare fundamentally different methods with the multimodal system proposed.<\/jats:p>","DOI":"10.3390\/s23156676","type":"journal-article","created":{"date-parts":[[2023,7,27]],"date-time":"2023-07-27T02:14:48Z","timestamp":1690424088000},"page":"6676","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["A LiDAR-Camera-Inertial-GNSS Apparatus for 3D Multimodal Dataset Collection in Woodland Scenarios"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5722-1774","authenticated-orcid":false,"given":"M\u00e1rio P.","family":"Crist\u00f3v\u00e3o","sequence":"first","affiliation":[{"name":"Institute of Systems and Robotics, Department of Electrical Engineering and Computers, University of Coimbra, 3030-290 Coimbra, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1447-0439","authenticated-orcid":false,"given":"David","family":"Portugal","sequence":"additional","affiliation":[{"name":"Institute of Systems and Robotics, Department of Electrical Engineering and Computers, University of Coimbra, 3030-290 Coimbra, Portugal"},{"name":"Department of Electrical Engineering and Computers, University of Coimbra, 3030-290 Coimbra, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3693-525X","authenticated-orcid":false,"given":"Afonso E.","family":"Carvalho\u00a0","sequence":"additional","affiliation":[{"name":"Institute of Systems and Robotics, Department of Electrical Engineering and Computers, University of Coimbra, 3030-290 Coimbra, Portugal"},{"name":"Department of Electrical Engineering and Computers, University of Coimbra, 3030-290 Coimbra, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2510-2412","authenticated-orcid":false,"given":"Jo\u00e3o Filipe","family":"Ferreira\u00a0","sequence":"additional","affiliation":[{"name":"Institute of Systems and Robotics, Department of Electrical Engineering and Computers, University of Coimbra, 3030-290 Coimbra, Portugal"},{"name":"Computational Intelligence and Applications Research Group, Department of Computer Science, School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,26]]},"reference":[{"key":"ref_1","first-page":"87","article-title":"ROS Integration of an Instrumented Bobcat T190 for the SEMFIRE Project","volume":"6","author":"Portugal","year":"2021","journal-title":"Robot. Oper. Syst. Ros Complet. Ref."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1386","DOI":"10.55417\/fr.2022046","article-title":"Robotic Precision Harvesting: Mapping, Localization, Planning and Control for a Legged Tree Harvester","volume":"2","author":"Jelavic","year":"2022","journal-title":"Field Robot."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Ferreira, J.F., Portugal, D., Andrada, M.E., Machado, P., Rocha, R.P., and Peixoto, P. (Forests, 2023). Sensing and Artificial Perception for Robots in Precision Forestry\u2014A Survey, Forests, in press.","DOI":"10.3390\/robotics12050139"},{"key":"ref_4","unstructured":"Crist\u00f3v\u00e3o, M. (2023, June 13). FRUC Multiple Sensor Forest Dataset Including Absolute, Map-Referenced Localization. Available online: https:\/\/zenodo.org\/record\/8139205."},{"key":"ref_5","unstructured":"Crist\u00f3v\u00e3o, M. (2023, June 13). ROS Streaming Sensors (Android App). Available online: https:\/\/github.com\/mjpc13\/SensorStreamer."},{"key":"ref_6","unstructured":"Thrun, S., Burgard, W., and Fox, D. (2005). Probabilistic Robotics, MIT Press. Intelligent Robotics and Autonomous Agents."},{"key":"ref_7","unstructured":"Santos, J.M., Couceiro, M.S., Portugal, D., and Rocha, R.P. (2014, January 14\u201315). Fusing sonars and LRF data to perform SLAM in reduced visibility scenarios. Proceedings of the 2014 IEEE International Conference on Autonomous Robot Systems and Competitions (ICARSC), Espinho, Portugal."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Oveland, I., Hauglin, M., Giannetti, F., Schipper Kj\u00f8rsvik, N., and Gobakken, T. (2018). Comparing Three Different Ground Based Laser Scanning Methods for Tree Stem Detection. Remote Sens., 10.","DOI":"10.3390\/rs10040538"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Proudman, A., Ramezani, M., and Fallon, M. (September, January 31). Online Estimation of Diameter at Breast Height (DBH) of Forest Trees Using a Handheld LiDAR. Proceedings of the 2021 European Conference on Mobile Robots (ECMR), Bonn, Germany.","DOI":"10.1109\/ECMR50962.2021.9568814"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1660","DOI":"10.1109\/LGRS.2020.3005166","article-title":"The Development and Evaluation of a Backpack LiDAR System for Accurate and Efficient Forest Inventory","volume":"18","author":"Su","year":"2021","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Sturm, J., Engelhard, N., Endres, F., Burgard, W., and Cremers, D. (2012, January 7\u201312). A benchmark for the evaluation of RGB-D SLAM systems. Proceedings of the 2012 IEEE\/RSJ International Conference on Intelligent Robots and Systems, Vilamoura-Algarve, Portugal.","DOI":"10.1109\/IROS.2012.6385773"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Sier, H., Qingqing, L., Xianjia, Y., Queralta, J.P., Zou, Z., and Westerlund, T. (2022). A Benchmark for Multi-Modal Lidar SLAM with Ground Truth in GNSS-Denied Environments. Remote Sens., 15.","DOI":"10.3390\/rs15133314"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3317","DOI":"10.1109\/LRA.2021.3064227","article-title":"FAST-LIO: A Fast, Robust LiDAR-Inertial Odometry Package by Tightly-Coupled Iterated Kalman Filter","volume":"6","author":"Xu","year":"2021","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"145","DOI":"10.5194\/isprs-archives-XLVIII-1-W1-2023-145-2023","article-title":"Real-Time Lidar-Inertial Positioning and Mapping for Forestry Automation","volume":"XLVIII-1\/W1-2023","author":"Faitli","year":"2023","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TGRS.2023.3293169","article-title":"WHU-Helmet: A Helmet-Based Multisensor SLAM Dataset for the Evaluation of Real-Time 3-D Mapping in Large-Scale GNSS-Denied Environments","volume":"61","author":"Li","year":"2023","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"416","DOI":"10.1002\/rob.21831","article-title":"RTAB-Map as an open-source lidar and visual simultaneous localization and mapping library for large-scale and long-term online operation","volume":"36","author":"Michaud","year":"2019","journal-title":"J. Field Robot."},{"key":"ref_17","unstructured":"Dellaert, F., and Contributors, G. (2023, June 13). Borglab\/gtsam. Available online: https:\/\/zenodo.org\/record\/7582634."},{"key":"ref_18","unstructured":"Kummerle, R., Grisetti, G., Strasdat, H., Konolige, K., and Burgard, W. (2011, January 9\u201313). G2o: A general framework for graph optimization. Proceedings of the 2011 IEEE International Conference on Robotics and Automation, Shanghai, China."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"428","DOI":"10.1109\/TITS.2009.2026444","article-title":"Nonlinear Constraint Network Optimization for Efficient Map Learning","volume":"10","author":"Grisetti","year":"2009","journal-title":"IEEE Trans. Intell. Transp. Syst."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Shan, T., and Englot, B. (2018, January 1\u20135). LeGO-LOAM: Lightweight and Ground-Optimized Lidar Odometry and Mapping on Variable Terrain. Proceedings of the IEEE\/RSJ International Conference on Intelligent Robots and Systems (IROS), Madrid, Spain.","DOI":"10.1109\/IROS.2018.8594299"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Kim, G., and Kim, A. (2018, January 1\u20135). Scan Context: Egocentric Spatial Descriptor for Place Recognition Within 3D Point Cloud Map. Proceedings of the IEEE\/RSJ International Conference on Intelligent Robots and Systems (IROS), Madrid, Spain.","DOI":"10.1109\/IROS.2018.8593953"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Ye, H., Chen, Y., and Liu, M. (2019, January 20\u201324). Tightly Coupled 3D Lidar Inertial Odometry and Mapping. Proceedings of the 2019 IEEE International Conference on Robotics and Automation (ICRA), Montreal, QC, Canada.","DOI":"10.1109\/ICRA.2019.8793511"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Xu, W., Cai, Y., He, D., Lin, J., and Zhang, F. (2021). FAST-LIO2: Fast Direct LiDAR-inertial Odometry. arXiv.","DOI":"10.1109\/TRO.2022.3141876"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Shan, T., Englot, B., Meyers, D., Wang, W., Ratti, C., and Daniela, R. (2020\u201324, January 24). LIO-SAM: Tightly-coupled Lidar Inertial Odometry via Smoothing and Mapping. Proceedings of the IEEE\/RSJ International Conference on Intelligent Robots and Systems (IROS), Las Vegas, NV, USA.","DOI":"10.1109\/IROS45743.2020.9341176"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"9043","DOI":"10.1109\/LRA.2022.3181357","article-title":"LOCUS 2.0: Robust and Computationally Efficient Lidar Odometry for Real-Time 3D Mapping","volume":"7","author":"Reinke","year":"2022","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Lin, J., and Zhang, F. (2022, January 23\u201327). R 3 LIVE: A Robust, Real-time, RGB-colored, LiDAR-Inertial-Visual tightly-coupled state Estimation and mapping package. Proceedings of the 2022 International Conference on Robotics and Automation (ICRA), Philadelphia, PA, USA.","DOI":"10.1109\/ICRA46639.2022.9811935"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"289","DOI":"10.1109\/TRO.2022.3199087","article-title":"Dynam-SLAM: An Accurate, Robust Stereo Visual-Inertial SLAM Method in Dynamic Environments","volume":"39","author":"Yin","year":"2022","journal-title":"IEEE Trans. Robot."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"504","DOI":"10.1109\/LRA.2022.3226074","article-title":"mVIL-Fusion: Monocular Visual-Inertial-LiDAR Simultaneous Localization and Mapping in Challenging Environments","volume":"8","author":"Wang","year":"2022","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Yuan, Z., Wang, Q., Cheng, K., Hao, T., and Yang, X. SDV-LOAM: Semi-Direct Visual-LiDAR Odometry and Mapping. IEEE Trans. Pattern Anal. Mach. Intell., 2023.","DOI":"10.1109\/TPAMI.2023.3262817"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"He, D., Xu, W., Chen, N., Kong, F., Yuan, C., and Zhang, F. (2023). Point-LIO: Robust High-Bandwidth Light Detection and Ranging Inertial Odometry. Adv. Intell. Syst. 5, 2200459.","DOI":"10.1002\/aisy.202200459"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1029","DOI":"10.1109\/LRA.2023.3236571","article-title":"KISS-ICP: In Defense of Point-to-Point ICP Simple, Accurate, and Robust Registration If Done the Right Way","volume":"8","author":"Vizzo","year":"2023","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Karfakis, P., Couceiro, M.S., and Portugal, D. (2023). NR5G-SAM: A SLAM Framework for Field Robot Applications based on 5G New Radio. Sensors, 23.","DOI":"10.3390\/s23115354"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Hess, W., Kohler, D., Rapp, H., and Andor, D. (2016, January 16\u201321). Real-Time Loop Closure in 2D LIDAR SLAM. Proceedings of the 2016 IEEE International Conference on Robotics and Automation (ICRA), Stockholm, Sweden.","DOI":"10.1109\/ICRA.2016.7487258"},{"key":"ref_34","unstructured":"FARO Technologies, Inc. (2023, June 13). GeoSLAM with ZEB1 Handheld SLAM Scanner. Available online: https:\/\/geoslam.com."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"4507","DOI":"10.1109\/LRA.2019.2933768","article-title":"Robust legged robot state estimation using factor graph optimization","volume":"4","author":"Wisth","year":"2019","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"3019","DOI":"10.1109\/LRA.2018.2849506","article-title":"Probabilistic terrain mapping for mobile robots with uncertain localization","volume":"3","author":"Fankhauser","year":"2018","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Nuchter, A., Lingemann, K., Hertzberg, J., and Surmann, H. (2005, January 18\u201320). 6D SLAM with approximate data association. Proceedings of the ICAR\u201905. Proceedings., 12th International Conference on Advanced Robotics, Seattle, WA, USA.","DOI":"10.1109\/ICAR.2005.1507419"},{"key":"ref_38","unstructured":"Li, Y., and Olson, E.B. (2010, January 3\u20138). Extracting general-purpose features from LIDAR data. Proceedings of the 2010 IEEE International Conference on Robotics and Automation, Anchorage, Alaska."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Xiao, K., Yu, W., Liu, W., Qu, F., and Ma, Z. (2022). High-Precision SLAM Based on the Tight Coupling of Dual Lidar Inertial Odometry for Multi-Scene Applications. Appl. Sci., 12.","DOI":"10.3390\/app12030939"},{"key":"ref_40","unstructured":"Livox (2023, June 13). LIO-Livox (A Robust LiDAR-Inertial Odometry for Livox LiDAR). Available online: https:\/\/github.com\/uuumxx\/lio-livox."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Zhang, J., and Singh, S. (2014, January 12\u201316). LOAM: Lidar Odometry and Mapping in real-time. Proceedings of the Robotics: Science and Systems Conference (RSS), Berkeley, CA, USA.","DOI":"10.15607\/RSS.2014.X.007"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1016\/S0141-3910(02)00045-9","article-title":"Thermal degradation of acrylonitrile\u2013butadiene\u2013styrene (ABS) blends","volume":"76","author":"Tiganis","year":"2002","journal-title":"Polym. Degrad. Stab."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2600","DOI":"10.1007\/s10924-019-01544-6","article-title":"Thermal, Rheological and Mechanical Properties of PETG\/rPETG Blends","volume":"27","author":"Dydek","year":"2019","journal-title":"J. Polym. Environment"},{"key":"ref_44","unstructured":"Rafael Miguel (2023, June 13). O-Solutions\u2014Choupal. Available online: https:\/\/o-solutions.pt\/wp-content\/uploads\/2020\/11\/17_Choupal-Coimbra-2019_10_05_RM.png."},{"key":"ref_45","unstructured":"Livox (2023, June 13). Livox Mapping. Available online: https:\/\/github.com\/Livox-SDK\/livox_mapping."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Madgwick, S.O., Harrison, A.J., and Vaidyanathan, R. (July, January 29). Estimation of IMU and MARG orientation using a gradient descent algorithm. Proceedings of the 2011 IEEE international conference on rehabilitation robotics, Zurich, Switzerland.","DOI":"10.1109\/ICORR.2011.5975346"},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Moore, T., and Stouch, D. (2014, January 15\u201318). A generalized extended kalman filter implementation for the robot operating system. Proceedings of the Intelligent Autonomous Systems 13: Proceedings of the 13th International Conference IAS-13, Padova, Italy.","DOI":"10.1007\/978-3-319-08338-4_25"},{"key":"ref_48","unstructured":"Dellaert, F. (2012). Factor Graphs and GTSAM: A Hands-on Introduction, Georgia Institute of Technology. Technical Report."},{"key":"ref_49","unstructured":"Agarwal, S., Mierle, K., and Team, T.C.S. (2023, June 13). Ceres Solver. Available online: https:\/\/github.com\/ceres-solver\/ceres-solver."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Rusu, R.B., and Cousins, S. (2011, January 9\u201313). 3d is here: Point cloud library (pcl). Proceedings of the 2011 IEEE International Conference on Robotics and Automation, Shanghai, China.","DOI":"10.1109\/ICRA.2011.5980567"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1007\/s10514-012-9321-0","article-title":"OctoMap: An efficient probabilistic 3D mapping framework based on octrees","volume":"34","author":"Hornung","year":"2013","journal-title":"Auton. Robot."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1109\/2.30720","article-title":"Using occupancy grids for mobile robot perception and navigation","volume":"22","author":"Elfes","year":"1989","journal-title":"Computer"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"6411","DOI":"10.1109\/LRA.2020.3013861","article-title":"UFOMap: An Efficient Probabilistic 3D Mapping Framework That Embraces the Unknown","volume":"5","author":"Duberg","year":"2020","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Carvalho, A.E., Ferreira, J.F., and Portugal, D. (Robot. Auton. Syst., 2023). 3D Traversability Analysis and Path Planning Based on Mechanical Effort for UGVs in Forest Environments, Robot. Auton. Syst., under review.","DOI":"10.1007\/978-3-031-22216-0_17"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/15\/6676\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T20:19:09Z","timestamp":1760127549000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/15\/6676"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,7,26]]},"references-count":54,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2023,8]]}},"alternative-id":["s23156676"],"URL":"https:\/\/doi.org\/10.3390\/s23156676","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,7,26]]}}}