{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,25]],"date-time":"2026-02-25T21:30:29Z","timestamp":1772055029878,"version":"3.50.1"},"reference-count":36,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,1,1]],"date-time":"2023-01-01T00:00:00Z","timestamp":1672531200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000132","name":"National Academy of Science Transportation Research Board","doi-asserted-by":"publisher","award":["163418-0399"],"award-info":[{"award-number":["163418-0399"]}],"id":[{"id":"10.13039\/100000132","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In the future, sensors mounted on uncrewed aerial systems (UASs) will play a critical role in increasing both the speed and safety of structural inspections. Environmental and safety concerns make structural inspections and maintenance challenging when conducted using traditional methods, especially for large structures. The methods developed and tested in the laboratory need to be tested in the field on real-size structures to identify their potential for full implementation. This paper presents results from a full-scale field implementation of a novel sensor equipped with UAS to measure non-contact transverse displacement from a pedestrian bridge. To this end, the authors modified and upgraded a low-cost system that previously showed promise in laboratory and small-scale outdoor settings so that it could be tested on an in-service bridge. The upgraded UAS system uses a commodity drone platform, low-cost sensors including a laser range-finder, and a computer vision-based algorithm with the aim of measuring bridge displacements under load indicative of structural problems. The aim of this research is to alleviate the costs and challenges associated with sensor attachment in bridge inspections and deliver the first prototype of a UAS-based non-contact out-of-plane displacement measurement. This work helps to define the capabilities and limitations of the proposed low-cost system in obtaining non-contact transverse displacement in outdoor experiments.<\/jats:p>","DOI":"10.3390\/s23010470","type":"journal-article","created":{"date-parts":[[2023,1,2]],"date-time":"2023-01-02T03:50:32Z","timestamp":1672631432000},"page":"470","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Sensor Equipped UAS for Non-Contact Bridge Inspections: Field Application"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9057-796X","authenticated-orcid":false,"given":"Roya","family":"Nasimi","sequence":"first","affiliation":[{"name":"The Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7105-7843","authenticated-orcid":false,"given":"Fernando","family":"Moreu","sequence":"additional","affiliation":[{"name":"The Department of Civil, Construction, and Environmental Engineering, The University of New Mexico, Albuquerque, NM 87131, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4466-8649","authenticated-orcid":false,"given":"G. 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Available online: https:\/\/infrastructurereportcard.org\/cat-item\/rail-infrastructure\/."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Moreu, F., Jo, H., Li, J., Kim, R.E., Cho, S., Kimmle, A., Scola, S., Le, H., Spencer, B.F., and LaFave, J.M. (2015). Dynamic Assessment of Timber Railroad Bridges Using Displacements. ASCE, 20.","DOI":"10.1061\/(ASCE)BE.1943-5592.0000726"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1820","DOI":"10.1016\/j.engstruct.2005.05.013","article-title":"Prediction of vertical deflections for a long-span prestressed concrete bridge structure","volume":"27","author":"Robertson","year":"2005","journal-title":"Eng. Struct."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Blake, A., Winstanley, G., and Wilkinson, W. (2009). Deriving displacement from a 3 axis accelerometer. Proc. CGAT, 1\u20136.","DOI":"10.1037\/e602482011-039"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"358","DOI":"10.1016\/j.engstruct.2017.04.021","article-title":"Low cost bridge load test: Calculating bridge displacement from acceleration for load assessment calculations","volume":"143","author":"Hester","year":"2017","journal-title":"Eng. Struct."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"152918","DOI":"10.1016\/j.aeue.2019.152918","article-title":"Evaluation of an optical energy harvester for SHM application","volume":"111","author":"Citroni","year":"2019","journal-title":"AEU-Int. J. Electron. Commun."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1016\/j.ndteint.2005.12.003","article-title":"A vision-based system for remote sensing of bridge displacement","volume":"39","author":"Lee","year":"2006","journal-title":"NDT E Int."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1177\/1475921708102108","article-title":"Vertical Displacement Measurements for Bridges Using Optical Fiber Sensors and CCD Cameras\u2014A Preliminary Study","volume":"8","author":"Chan","year":"2009","journal-title":"Struct. Health Monit."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"164","DOI":"10.1016\/j.engstruct.2014.04.051","article-title":"Non-contact measurement of the dynamic displacement of railway bridges using an advanced video-based system","volume":"75","author":"Ribeiro","year":"2014","journal-title":"Eng. Struct."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Aliansyah, Z., Shimasaki, K., Senoo, T., Ishii, I., and Umemoto, S. (2021). Single-Camera-Based Bridge Structural Displacement Measurement with Traffic Counting. Sensors, 21.","DOI":"10.3390\/s21134517"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1007\/s13349-018-0285-4","article-title":"Bridge inspection: Human performance, unmanned aerial systems and automation","volume":"8","author":"Dorafshan","year":"2018","journal-title":"J. Civ. Struct. Health Monit."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1177\/0361198118780825","article-title":"Field Application of UAS-Based Bridge Inspection","volume":"2672","author":"Seo","year":"2018","journal-title":"Transp. Res. Rec. J. Transp. Res. Board"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1007\/s13349-017-0261-4","article-title":"Review of machine-vision based methodologies for displacement measurement in civil structures","volume":"8","author":"Xu","year":"2018","journal-title":"J. Civ. Struct. Health Monit."},{"key":"ref_16","unstructured":"Wood, R.L., Nasimi, M., Yang, B., Wittich, C.E., Steelman, J.S., Puckett, J.A., Linzell, D.G., Zhu, J., and Mohammadi, M.E. (2022). M107: Outdoor Laboratory and Testbed for Bridge Health, Department of Transportation."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Wu, Z., Chen, G., Ding, Q., Yuan, B., and Yang, X. (2021). Three-Dimensional Reconstruction-Based Vibration Measurement of Bridge Model Using UAVs. Appl. Sci., 11.","DOI":"10.3390\/app11115111"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Xuan Mung, N., Nguyen, N.P., Pham, D.B., Dao, N.N., and Hong, S.K. (2022). Synthesized Landing Strategy for Quadcopter to Land Precisely on a Vertically Moving Apron. Mathematics, 10.","DOI":"10.3390\/math10081328"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"83580","DOI":"10.1109\/ACCESS.2022.3197181","article-title":"Quadcopter Precision Landing on Moving Targets via Disturbance Observer-based Controller and Autonomous Landing Planner","volume":"10","author":"Nguyen","year":"2022","journal-title":"IEEE Access"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Carroll, S., Satme, J., Alkharusi, S., Vitzilaios, N., Downey, A., and Rizos, D. (2021). Drone-Based Vibration Monitoring and Assessment of Structures. Appl. Sci., 11.","DOI":"10.3390\/app11188560"},{"key":"ref_21","first-page":"68","article-title":"Unmanned aerial vehicle acquisition of three-dimensional digital image correlation measurements for structural health monitoring of bridges","volume":"Volume 10169","author":"Reagan","year":"2017","journal-title":"Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, and Civil Infrastructure 2017"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Gillins, M.N., Gillins, D.T., and Parrish, C. (2016, January 14\u201317). Cost-Effective Bridge Safety Inspections Using Unmanned Aircraft Systems (UAS). Proceedings of the Geotechnical and Structural Engineering Congress 2016, Phoenix, AZ, USA.","DOI":"10.1061\/9780784479742.165"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1061\/(ASCE)CF.1943-5509.0000145","article-title":"Hauser Small-Format Aerial Photography for Highway-Bridge Monitoring","volume":"25","author":"Chen","year":"2011","journal-title":"J. Perform. Constr. Facil."},{"key":"ref_24","unstructured":"Chan, B., Anstice, D., Pettigrew, T., and Saul, I. (2017, January 3\u20136). Photogrammetric modelling and drones for the effective inspection and management of major steel truss bridges: Case study. Proceedings of the Austroads Bridge Conference 10th\u20142017, Melbourne, Australia."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.autcon.2006.12.010","article-title":"A UAV for bridge inspection: Visual servoing control law with orientation limits","volume":"17","author":"Metni","year":"2007","journal-title":"Autom. Constr."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"759","DOI":"10.1111\/mice.12141","article-title":"Vision-Based Automated Crack Detection for Bridge Inspection","volume":"30","author":"Yeum","year":"2015","journal-title":"Comput. Aided Civ. Infrastruct. Eng."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s40327-015-0029-z","article-title":"Visual monitoring of civil infrastructure systems via camera-equipped Unmanned Aerial Vehicles (UAVs): A review of related works","volume":"4","author":"Ham","year":"2016","journal-title":"Vis. Eng."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"104376","DOI":"10.1016\/j.autcon.2022.104376","article-title":"UAV-based bridge geometric shape measurement using automatic bridge component detection and distributed multi-view reconstruction","volume":"140","author":"Xu","year":"2022","journal-title":"Autom. Constr."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"107769","DOI":"10.1016\/j.measurement.2020.107769","article-title":"Swaying displacement measurement for structural monitoring using computer vision and an unmanned aerial vehicle","volume":"159","author":"Khuc","year":"2020","journal-title":"Measurement"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"106446","DOI":"10.1016\/j.ymssp.2019.106446","article-title":"Non-contact vibration monitoring of rotating wind turbines using a semi-autonomous UAV","volume":"138","author":"Khadka","year":"2019","journal-title":"Mech. Syst. Signal Process."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1111\/mice.12338","article-title":"Structural displacement measurement using an unmanned aerial system","volume":"33","author":"Yoon","year":"2018","journal-title":"Comput. Aided Civ. Infrastruct. Eng."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1111\/mice.12652","article-title":"A methodology for measuring the total displacements of structures using a laser\u2013camera system","volume":"36","author":"Nasimi","year":"2021","journal-title":"Comput. Civ.-Aided Infrastruct. Eng."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"04021045","DOI":"10.1061\/(ASCE)EM.1943-7889.0001939","article-title":"Development and Implementation of a Laser\u2013Camera\u2013UAV System to Measure Total Dynamic Transverse Displacement","volume":"147","author":"Nasimi","year":"2021","journal-title":"J. Eng. Mech."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"514","DOI":"10.1177\/03611981221075618","article-title":"Developing Enhanced Unmanned Aerial Vehicle Sensing System for Practical Bridge Inspections Using Field Experiments","volume":"2676","author":"Nasimi","year":"2022","journal-title":"Transp. Res. Rec. J. Transp. Res. Board"},{"key":"ref_35","unstructured":"(2022, October 22). RSV-150. Remote Sensing Vibrometer. Available online: https:\/\/www.polytec.com\/us\/vibrometry\/products\/special-application-vibrometers\/rsv-150-remote-sensing-vibrometer."},{"key":"ref_36","unstructured":"Gimble Lock (2022, October 22). Euler Angle Features. Available online: https:\/\/en.wikipedia.org\/wiki\/Gimbal_lock#Loss_of_a_degree_of_freedom_with_Euler_angles."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/1\/470\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T17:55:24Z","timestamp":1760118924000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/1\/470"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,1]]},"references-count":36,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2023,1]]}},"alternative-id":["s23010470"],"URL":"https:\/\/doi.org\/10.3390\/s23010470","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,1]]}}}