{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:06:09Z","timestamp":1760241969692,"version":"build-2065373602"},"reference-count":29,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2018,11,18]],"date-time":"2018-11-18T00:00:00Z","timestamp":1542499200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJGI"],"abstract":"<jats:p>Micro aerial vehicles (MAVs) have been acknowledged as an influential technology for indoor search and rescue operations. The time constraint is a crucial factor in most search and rescue operations. The employed MAVs in indoor environments are characterized by short endurance flight time and limited payload weights. Hence, adding more batteries to extend the flight time is practically not feasible. Typically, most of the indoor missions\u2019 environments might not be accessed and remain unknown. Working in such environments requires effective exploration and information gathering to save time and maximize the coverage area. Furthermore, due to the dynamism of such environments, choosing the least risky trajectory is an important task. This paper proposes a real-time active exploration technique which is capable of efficiently generating paths that minimize the vehicle\u2019s risk and maximize the coverage area. Furthermore, it accomplishes real-time monitoring of sudden changes in the estimated map, due to the dynamic objects, by reevaluating at real-time the destination and trajectory to minimize the risk on the chosen path and simultaneously preserving the maximization of the coverage area. Ultimately, recording the implemented trajectory of the vehicle also assists in time-saving as the vehicle depends on this trajectory during the exit process. The performance of the technique is studied under static and dynamic environments and is also compared with different algorithms.<\/jats:p>","DOI":"10.3390\/ijgi7110450","type":"journal-article","created":{"date-parts":[[2018,11,21]],"date-time":"2018-11-21T11:23:27Z","timestamp":1542799407000},"page":"450","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Real-Time Efficient Exploration in Unknown Dynamic Environments Using MAVs"],"prefix":"10.3390","volume":"7","author":[{"given":"Haytham","family":"Mohamed","sequence":"first","affiliation":[{"name":"Department of Geomatics Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adel","family":"Moussa","sequence":"additional","affiliation":[{"name":"Department of Geomatics Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada"},{"name":"Department of Electrical and Computer Engineering, Port-Said University, Port-Said 42523, Egypt"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohamed","family":"Elhabiby","sequence":"additional","affiliation":[{"name":"Public Works Department, Ain Shams University, Cairo 11566, Egypt"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Naser","family":"El-Sheimy","sequence":"additional","affiliation":[{"name":"Department of Geomatics Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,11,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Quintero M., C.G., O\u00f1ate L\u00f3pez, J., and Bertel R., F.A. (2012, January 1\u20135). Intelligent exploration and surveillance algorithms for multi-agents robotics systems. Proceedings of the 38th Latin America Conference on Informatics, Medellin, Colombia.","DOI":"10.1109\/CLEI.2012.6427178"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1177\/105971239900700204","article-title":"Integrating Exploration and Localization for Mobile Robots","volume":"7","author":"Yamauchi","year":"1999","journal-title":"Adapt. Behav."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Tijsma, A.D., Drugan, M.M., and Wiering, M.A. (2016, January 6\u20139). Comparing exploration strategies for Q-learning in random stochastic mazes. Proceedings of the 2016 IEEE Symposium Series on Computational Intelligence (SSCI), Athens, Greece.","DOI":"10.1109\/SSCI.2016.7849366"},{"key":"ref_4","unstructured":"Sugiyama, H., Tsujioka, T., and Murata, M. (2005, January 19\u201321). Collaborative Movement of Rescue Robots for Reliable and Effective Networking in Disaster Area. Proceedings of the 2005 International Conference on Collaborative Computing: Networking, Applications and Worksharing, San Jose, CA, USA."},{"key":"ref_5","unstructured":"Hougen, D.F., Benjaafar, S., Bonney, J.C., Budenske, J.R., Dvorak, M., Gini, M., French, H., Krantz, D.G., Li, P.Y., and Malver, F. (2000, January 24\u201328). A miniature robotic system for reconnaissance and surveillance. Proceedings of the 2000 IEEE International Conference on Robotics and Automation, San Francisco, CA, USA."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Hoffmann, R., Weikersdorfer, D., and Conradt, J. (2013, January 25\u201327). Autonomous indoor exploration with an event-based visual SLAM system. Proceedings of the 2013 European Conference on Mobile Robots, Barcelona, Spain.","DOI":"10.1109\/ECMR.2013.6698817"},{"key":"ref_7","first-page":"151","article-title":"A simple local path planning algorithm for autonomous mobile robots","volume":"5","author":"Buniyamin","year":"2011","journal-title":"Int. J. Syst. Appl. Eng. Dev."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Surgade, A., Bhavsar, N., Thale, K., Deshpande, A., and Mohite, D. (2017, January 1\u20132). Real-time navigation for indoor environment. Proceedings of the 2017 International Conference on Advances in Computing, Communication and Control (ICAC3), Mumbai, India.","DOI":"10.1109\/ICAC3.2017.8318769"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1007\/978-3-319-28872-7_37","article-title":"Polynomial trajectory planning for aggressive quadrotor flight in dense indoor environments","volume":"Volume 114","author":"Richter","year":"2016","journal-title":"Springer Tracts in Advanced Robotics"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1109\/12.663776","article-title":"A note on the complexity of Dijkstra\u2019s algorithm for graphs with weighted vertices","volume":"47","author":"Barbehenn","year":"1998","journal-title":"IEEE Trans. Comput."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Kang, H.I., Lee, B., and Kim, K. (2008, January 19\u201320). Path Planning Algorithm Using the Particle Swarm Optimization and the Improved Dijkstra Algorithm. Proceedings of the 2008 IEEE Pacific-Asia Workshop on Computational Intelligence and Industrial Application, Wuhan, China.","DOI":"10.1109\/PACIIA.2008.376"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1109\/TAES.2007.357150","article-title":"Novel minimum time trajectory planning in terrain following flights","volume":"43","author":"Malaek","year":"2007","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Tsai, Y.-J., Lee, C.-S., Lin, C.-L., and Huang, C.-H. (2015). Development of Flight Path Planning for Multirotor Aerial Vehicles. Aerospace, 2.","DOI":"10.3390\/aerospace2020171"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1109\/TAES.2012.6129620","article-title":"Dynamic Based Cost Functions for TF\/TA Flights","volume":"48","author":"Malaek","year":"2012","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Ferguson, D., and Stentz, A. (2006, January 9\u201315). Anytime RRTs. Proceedings of the 2006 IEEE\/RSJ International Conference on Intelligent Robots and Systems, Beijing, China.","DOI":"10.1109\/IROS.2006.282100"},{"key":"ref_16","unstructured":"Lavalle, S.M., Lavalle, S.M., and Kuffner, J.J. (2000, January 16\u201318). Rapidly-Exploring Random Trees: Progress and Prospects. Proceedings of the Fourth International Workshop on Algorithmic Foundations of Robotics, Hanover, NH, USA."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.robot.2015.02.007","article-title":"Intelligent bidirectional rapidly-exploring random trees for optimal motion planning in complex cluttered environments","volume":"68","author":"Qureshi","year":"2015","journal-title":"Robot. Auton. Syst."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Xinggang, W., Cong, G., and Yibo, L. (June, January 31). Variable probability based bidirectional RRT algorithm for UAV path planning. Proceedings of the 26th Chinese Control and Decision Conference (2014 CCDC), Changsha, China.","DOI":"10.1109\/CCDC.2014.6852537"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Acu\u00f1a, R., Terrones, A., Certad-H, N., Ferm\u00edn-Le\u00f3n, L., and Fern\u00e1ndez-L\u00f3pez, G. (2012, January 23\u201326). Dynamic Potential Field Generation Using Movement Prediction. Proceedings of the Fifteenth International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, Baltimore, MD, USA.","DOI":"10.1142\/9789814415958_0098"},{"key":"ref_20","unstructured":"Bruce, J., and Veloso, M. (October, January 30). Real-time randomized path planning for robot navigation. Proceedings of the IEEE\/RSJ International Conference on Intelligent Robots and System, Lausanne, Switzerland."},{"key":"ref_21","unstructured":"Ferguson, D., Kalra, N., and Stentz, A. (2006, January 15\u201319). Replanning with RRTs. Proceedings of the IEEE International Conference on Robotics and Automation, Orlando, FL, USA."},{"key":"ref_22","unstructured":"Li, T.Y., and Shie, Y.C. (2002, January 11\u201315). An incremental learning approach to motion planning with roadmap management. Proceedings of the 2002 IEEE International Conference on Robotics and Automation, Washington, DC, USA."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Zucker, M., Kuffner, J., and Branicky, M. (2007, January 10\u201314). Multipartite RRTs for Rapid Replanning in Dynamic Environments. Proceedings of the 2007 IEEE International Conference on Robotics and Automation, Roma, Italy.","DOI":"10.1109\/ROBOT.2007.363553"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Mohamed, H., Moussa, A., Elhabiby, M., El-Sheimy, N., and Sesay, A. (2017). A Novel Real-Time Reference Key Frame Scan Matching Method. Sensors, 17.","DOI":"10.3390\/s17051060"},{"key":"ref_25","unstructured":"Mohamed, H., Moussa, A., Elhabiby, M., El-Sheimy, N., and Sesay, A.B. (2017, January 6\u20138). Corner Features Aided Indoor Slam for Unmanned Vehicles. Proceedings of the 10th International Conference on Mobile Mapping Technology (MMT), Cairo, Egypt."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1145\/1322432.1322434","article-title":"2D Euclidean distance transform algorithms","volume":"40","author":"Fabbri","year":"2008","journal-title":"ACM Comput. Surv."},{"key":"ref_27","unstructured":"Wu, Q. (2006). Incremental Routing Algorithms for Dynamic Transportation Networks. [Master\u2019s Thesis, University of Calgary]."},{"key":"ref_28","unstructured":"Smith, S.W. (1999). The Scientist and Engineer\u2019s Guide to Digital Signal Processing, California Technical Pub.. [2nd ed.]."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Mostafa, M., Zahran, S., Moussa, A., El-Sheimy, N., Sesay, A., Mostafa, M., Zahran, S., Moussa, A., El-Sheimy, N., and Sesay, A. (2018). Radar and Visual Odometry Integrated System Aided Navigation for UAVS in GNSS Denied Environment. Sensors, 18.","DOI":"10.3390\/s18092776"}],"container-title":["ISPRS International Journal of Geo-Information"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2220-9964\/7\/11\/450\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:30:28Z","timestamp":1760196628000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2220-9964\/7\/11\/450"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,11,18]]},"references-count":29,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2018,11]]}},"alternative-id":["ijgi7110450"],"URL":"https:\/\/doi.org\/10.3390\/ijgi7110450","relation":{},"ISSN":["2220-9964"],"issn-type":[{"type":"electronic","value":"2220-9964"}],"subject":[],"published":{"date-parts":[[2018,11,18]]}}}