{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,18]],"date-time":"2026-07-18T16:27:18Z","timestamp":1784392038803,"version":"3.55.0"},"reference-count":36,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2018,4,28]],"date-time":"2018-04-28T00:00:00Z","timestamp":1524873600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, we propose UILoc, an unsupervised indoor localization scheme that uses a combination of smartphone sensors, iBeacons and Wi-Fi fingerprints for reliable and accurate indoor localization with zero labor cost. Firstly, compared with the fingerprint-based method, the UILoc system can build a fingerprint database automatically without any site survey and the database will be applied in the fingerprint localization algorithm. Secondly, since the initial position is vital to the system, UILoc will provide the basic location estimation through the pedestrian dead reckoning (PDR) method. To provide accurate initial localization, this paper proposes an initial localization module, a weighted fusion algorithm combined with a k-nearest neighbors (KNN) algorithm and a least squares algorithm. In UILoc, we have also designed a reliable model to reduce the landmark correction error. Experimental results show that the UILoc can provide accurate positioning, the average localization error is about 1.1 m in the steady state, and the maximum error is 2.77 m.<\/jats:p>","DOI":"10.3390\/s18051378","type":"journal-article","created":{"date-parts":[[2018,4,30]],"date-time":"2018-04-30T03:45:49Z","timestamp":1525059949000},"page":"1378","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":35,"title":["Unsupervised Indoor Localization Based on Smartphone Sensors, iBeacon and Wi-Fi"],"prefix":"10.3390","volume":"18","author":[{"given":"Jing","family":"Chen","sequence":"first","affiliation":[{"name":"Jiangnan University, School of Internet of Thing Engineering, Wuxi 214122, China"},{"name":"Engineering Research Center of Internet of Things Technology Applications, Ministry of Education, Wuxi 214122, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yi","family":"Zhang","sequence":"additional","affiliation":[{"name":"Jiangnan University, School of Internet of Thing Engineering, Wuxi 214122, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Xue","sequence":"additional","affiliation":[{"name":"Jiangnan University, School of Internet of Thing Engineering, Wuxi 214122, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,4,28]]},"reference":[{"key":"ref_1","unstructured":"Bahl, P., and Padmanabhan, V.N. (2000, January 26\u201330). RADAR: An in-building RF-based user location and tracking system. Proceedings of the Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies, Tel Aviv, Israel."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1109\/MCOM.2015.7060497","article-title":"WiFi-based indoor positioning","volume":"53","author":"Yang","year":"2015","journal-title":"IEEE Commun. Mag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"701","DOI":"10.1023\/B:WINE.0000044029.06344.dd","article-title":"LANDMARC: Indoor location sensing using active rfid","volume":"10","author":"Ni","year":"2004","journal-title":"Wirel. Netw."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Zhuang, Y., Yang, J., Li, Y., Qi, L., and El-Sheimy, N. (2016). Smartphone-based indoor localization with bluetooth low energy beacons. Sensors, 16.","DOI":"10.3390\/s16050596"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Chen, Z., Zhu, Q., Jiang, H., and Soh, Y.C. (2015, January 15\u201317). Indoor localization using smartphone sensors and iBeacons. Proceedings of the 2015 IEEE 10th Conference on Industrial Electronics and Applications (ICIEA), Auckland, New Zealand.","DOI":"10.1109\/ICIEA.2015.7334389"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Zou, H., Jiang, H., Luo, Y., Zhu, J., Lu, X., and Xie, L. (2016). BlueDetect: An iBeacon-enabled scheme for accurate and energy-efficient indoor-outdoor detection and seamless location-based service. Sensors, 16.","DOI":"10.3390\/s16020268"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1109\/MPRV.2014.24","article-title":"Building a practical Wi-Fi-based indoor navigation system","volume":"13","author":"Han","year":"2014","journal-title":"IEEE Pervasive Comput."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"693","DOI":"10.1109\/LCOMM.2013.022213.122885","article-title":"Radio map update automation for WiFi positioning systems","volume":"17","author":"Lim","year":"2013","journal-title":"IEEE Commun. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Rai, A., Chintalapudi, K.K., Padmanabhan, V.N., and Sen, R. (2012, January 22\u201326). Zee: Zero-effort crowdsourcing for indoor localization. Proceedings of the 18th Annual International Conference on Mobile Computing and Networking, Istanbul, Turkey.","DOI":"10.1145\/2348543.2348580"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Yang, S., Dessai, P., Verma, M., and Gerla, M. (2013, January 14\u201319). Freeloc: Calibration-free crowdsourced indoor localization. Proceedings of the 2013 IEEE INFOCOM, Turin, Italy.","DOI":"10.1109\/INFCOM.2013.6567054"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"444","DOI":"10.1109\/TMC.2014.2320254","article-title":"Smartphones based crowdsourcing for indoor localization","volume":"14","author":"Wu","year":"2015","journal-title":"IEEE Trans. Mob. Comput."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2906","DOI":"10.1109\/JSEN.2014.2382568","article-title":"SmartPDR: Smartphone-based pedestrian dead reckoning for indoor localization","volume":"15","author":"Kang","year":"2015","journal-title":"IEEE Sens. J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2418","DOI":"10.1109\/JSAC.2015.2430281","article-title":"Location fingerprinting with bluetooth low energy beacons","volume":"33","author":"Faragher","year":"2015","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1540","DOI":"10.1109\/TII.2016.2579265","article-title":"Smartphone inertial sensor-based indoor localization and tracking with iBeacon corrections","volume":"12","author":"Chen","year":"2016","journal-title":"IEEE Trans. Ind. Inform."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Golestanian, M., and Poellabauer, C. (2016, January 5\u20138). Indoor localization using multi-range beaconing: Poster. Proceedings of the 17th ACM International Symposium on Mobile Ad Hoc Networking and Computing, Paderborn, Germany.","DOI":"10.1145\/2942358.2942414"},{"key":"ref_16","first-page":"2369103","article-title":"Method for improving indoor positioning accuracy using extended kalman filter","volume":"2016","author":"Lee","year":"2016","journal-title":"Mob. Inf. Syst."},{"key":"ref_17","first-page":"1162","article-title":"Adaptive distance estimation based on RSSI in 802.15. 4 network","volume":"22","author":"Botta","year":"2013","journal-title":"Radioengineering"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Boukerche, A., Oliveira, H.A., Nakamura, E.F., and Loureiro, A.A. (2007). Localization systems for wireless sensor networks. IEEE Wirel. Commun., 14.","DOI":"10.1109\/MWC.2007.4407221"},{"key":"ref_19","unstructured":"Bahl, P., Padmanabhan, V.N., and Balachandran, A. (2018, April 12). Enhancements to the RADAR User Location and Tracking System. Available online: https:\/\/www.microsoft.com\/en-us\/research\/publication\/enhancements-to-the-radar-user-location-and-tracking-system\/."},{"key":"ref_20","unstructured":"Castro, P., Chiu, P., Kremenek, T., and Muntz, R. (October, January 30). A probabilistic room location service for wireless networked environments. Proceedings of the 3rd International Conference on Ubiquitous Computing, Atlanta, GA, USA."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Youssef, M., and Agrawala, A. (2005, January 6\u20138). The Horus WLAN location determination system. Proceedings of the 3rd International Conference on Mobile Systems, Applications, and Services, Seattle, WA, USA.","DOI":"10.1145\/1067170.1067193"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1007\/s11276-006-0725-7","article-title":"The Horus WLAN Location Determination System","volume":"14","author":"Youssef","year":"2008","journal-title":"Wirel. Netw."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Moghtadaiee, V., Dempster, A.G., and Lim, S. (2011, January 21\u201323). Indoor localization using fm radio signals: A fingerprinting approach. Proceedings of the 2011 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Guimar\u00e3es, Portugal.","DOI":"10.1109\/IPIN.2011.6071932"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1109\/TBC.2014.2322771","article-title":"Indoor location fingerprinting using FM radio signals","volume":"60","author":"Moghtadaiee","year":"2014","journal-title":"IEEE Trans. Broadcast."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Jin, Y., Toh, H.S., Soh, W.S., and Wong, W.C. (2011, January 21\u201325). A robust dead-reckoning pedestrian tracking system with low cost sensors. Proceedings of the 2011 IEEE International Conference on Pervasive Computing and Communications (PerCom), Seattl, WA, USA.","DOI":"10.1109\/PERCOM.2011.5767590"},{"key":"ref_26","first-page":"1133","article-title":"Step counting algorithm based on FSM using acceleration differential","volume":"10","author":"Wang","year":"2016","journal-title":"J. Front. Comput. Sci. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Alzantot, M., and Youssef, M. (2012, January 1\u20134). UPTIME: Ubiquitous pedestrian tracking using mobile phones. Proceedings of the 2012 IEEE theWireless Communications and Networking Conference (WCNC), Shanghai, China.","DOI":"10.1109\/WCNC.2012.6214359"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Wang, H., Sen, S., Elgohary, A., Farid, M., Youssef, M., and Choudhury, R.R. (2012, January 25\u201329). No need to war-drive: Unsupervised indoor localization. Proceedings of the 10th International Conference on Mobile Systems, Applications, and Services, Lake District, UK.","DOI":"10.1145\/2307636.2307655"},{"key":"ref_29","unstructured":"Yang, F., Lu, J.L., Theoleyre, F., Shu, W., and Wu, M.Y. (2015, January 20\u201322). Dynamic active area clustering with inertial information for fingerprinting based indoor localization systems. Proceedings of the IFIP Networking Conference (IFIP Networking), Toulouse, France."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Pelant, J., Tlamsa, Z., Benes, V., Polak, L., Kaller, O., Bolecek, L., Kufa, J., Sebesta, J., and Kratochvil, T. (2017, January 19\u201320). BLE device indoor localization based on RSS fingerprinting mapped by propagation modes. Proceedings of the 2017 27th International Conference on Radioelektronika (RADIOELEKTRONIKA), Brno, Czech Republic.","DOI":"10.1109\/RADIOELEK.2017.7937584"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"4115","DOI":"10.1007\/s11277-017-4371-4","article-title":"Bluetooth Indoor Positioning Based on RSSI and Kalman Filter","volume":"96","author":"Zhou","year":"2017","journal-title":"Wirel. Pers. Commun."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"R\u00f6besaat, J., Zhang, P., Abdelaal, M., and Theel, O. (2017). An Improved BLE Indoor Localization with Kalman-Based Fusion: An Experimental Study. Sensors, 17.","DOI":"10.3390\/s17050951"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Davidson, P., Collin, J., and Takala, J. (2010, January 14\u201315). Application of particle filters for indoor positioning using floor plans. Proceedings of the Ubiquitous Positioning Indoor Navigation and Location Based Service (UPINLBS), Kirkkonummi, Finland.","DOI":"10.1109\/UPINLBS.2010.5653830"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Widyawan, K.M., and Beauregard, S. (2008, January 27). A backtracking particle filter for fusing building plans with PDR displacement estimates. Proceedings of the 5th Workshop on Positioning, Navigation and Communication, Hannover, Germany.","DOI":"10.1109\/WPNC.2008.4510376"},{"key":"ref_35","unstructured":"YouTube (2018, April 12). UILoc Experiment. Available online: https:\/\/youtu.be\/o6880f2uv9o."},{"key":"ref_36","unstructured":"YouTube (2018, April 12). Summary of Different Localization Algorithms. Available online: https:\/\/youtu.be\/kLvYlNMLtww."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/5\/1378\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:02:36Z","timestamp":1760194956000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/5\/1378"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,4,28]]},"references-count":36,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2018,5]]}},"alternative-id":["s18051378"],"URL":"https:\/\/doi.org\/10.3390\/s18051378","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,4,28]]}}}