{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T08:00:14Z","timestamp":1777622414807,"version":"3.51.4"},"reference-count":26,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2019,5,30]],"date-time":"2019-05-30T00:00:00Z","timestamp":1559174400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61771488"],"award-info":[{"award-number":["61771488"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61801497"],"award-info":[{"award-number":["61801497"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61631020"],"award-info":[{"award-number":["61631020"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, we propose a novel indoor passive localization approach called eigenspace-based DOA with direct-path recognition (ES-DPR), based on a DOA estimation algorithm with multiple omnidirectional antennas deployed in a uniform linear array (ULA). To address the multipath propagation interference problem in the indoor environments, we utilize the azimuth and RSS estimation results, which are calculated by using the eigenspace-based DOA (ES-DOA) algorithm, in a novel style. A direct-path bearing recognition algorithm is introduced to identify the real DOA of the signal source in different indoor environments, by combining the azimuth and RSS estimation with ensemble learning methods. Numerical simulations are conducted to verify the validity and superiority of the proposed method. The results show that the proposed ES-DPR method can achieve high resolution and has strong anti-noise capability in dealing with the multipath signals, and the direct-path recognition algorithm is reliable and robust in different indoor environments, even in undetectable direct-path conditions.<\/jats:p>","DOI":"10.3390\/s19112482","type":"journal-article","created":{"date-parts":[[2019,5,30]],"date-time":"2019-05-30T11:07:44Z","timestamp":1559214464000},"page":"2482","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["ES-DPR: A DOA-Based Method for Passive Localization in Indoor Environments"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1412-2709","authenticated-orcid":false,"given":"Zhang","family":"Chen","sequence":"first","affiliation":[{"name":"College of Communications Engineering, PLA Army Engineering University, Nanjing 210007, China"},{"name":"The Sixty-third Institute, National University of Defense Technology, Nanjing 210007, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jinlong","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Communications Engineering, PLA Army Engineering University, Nanjing 210007, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,5,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1109\/SURV.2009.090103","article-title":"A Survey of Indoor Positioning Systems for Wireless Personal Networks","volume":"11","author":"Gu","year":"2009","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1327","DOI":"10.1109\/COMST.2016.2632427","article-title":"Recent Advances in Indoor Localization: A Survey on Theoretical Approaches and Applications","volume":"19","author":"Yassin","year":"2017","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_3","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 IEEE Infocom, Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies (Cat. No.00CH37064), Tel Aviv, Israel."},{"key":"ref_4","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, New York, NY, USA.","DOI":"10.1145\/1067170.1067193"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"825","DOI":"10.1016\/j.comnet.2004.09.004","article-title":"Statistical learning theory for location fingerprinting in wireless LANs","volume":"47","author":"Brunato","year":"2005","journal-title":"Comput. Netw."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1109\/COMST.2015.2464084","article-title":"Wi-Fi Fingerprint-Based Indoor Positioning: Recent Advances and Comparisons","volume":"18","author":"He","year":"2017","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Chen, Z., and Wang, J. (2018). GROF: Indoor Localization Using a Multiple-Bandwidth General Regression Neural Network and Outlier Filter. Sensors, 18.","DOI":"10.3390\/s18113723"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1109\/SURV.2009.090308","article-title":"A survey on TOA based wireless localization and NLOS mitigation techniques","volume":"11","author":"Guvenc","year":"2009","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Keunecke, K., and Scholl, G. (2013, January 28\u201331). Deriving 2d Toa\/Tdoa IEEE 802.11 g\/n\/ac Location Accuracy from an Experimentally Verified Fading Channel Model. Proceedings of the International Conference on Indoor Positioning and Indoor Navigation, Montbeliard-Belfort, France.","DOI":"10.1109\/IPIN.2013.6817849"},{"key":"ref_10","unstructured":"Vasishty, D., Kumar, S., and Katabi, D. (2016, January 16\u201318). Decimeter-Level Localization with a Single WiFi Access Point. Proceedings of the USENIX Symposium on Networked Systems Design and Implementation, Santa Clara, CA, USA."},{"key":"ref_11","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":"Commun. Mag. IEEE"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Exel, R., Gaderer, G., and Loschmidt, P. (2010, January 18\u201321). Localisation of Wireless LAN Nodes Using Accurate TDoA Measurements. Proceedings of the Wireless Communications & Networking Conference, Sydney, NSW, Australia.","DOI":"10.1109\/WCNC.2010.5506651"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Xie, T., Zhang, C., Li, Y., Jiang, H., and Wang, Z. (2017, January 6\u20139). An Enhanced TDoA Approach Handling Multipath Interference in Wi-Fi Based Indoor Localization Systems. Proceedings of the 60th International Midwest Symposium on Circuits and Systems, Boston, MA, USA.","DOI":"10.1109\/MWSCAS.2017.8052885"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Kotaru, M., Joshi, K., Bharadia, D., and Katti, S. (2015, January 17\u201324). SpotFi: Decimeter Level Localization Using WiFi. Proceedings of the ACM, Stanford, CA, USA.","DOI":"10.1145\/2785956.2787487"},{"key":"ref_15","unstructured":"Xiong, J., and Jamieson, K. (2013, January 2\u20135). ArrayTrack: A Fine-Grained Indoor Location System. Proceedings of the USENIX Symposium on Networked Systems Design and Implementation, Berkeley, CA, USA."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1109\/TAP.1986.1143830","article-title":"Multiple Emitter Location and Signal Parameters Estimation","volume":"34","author":"Schmidt","year":"1986","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"984","DOI":"10.1109\/29.32276","article-title":"ESPRIT-estimation of signal parameters via rotational invariance techniques","volume":"37","author":"Roy","year":"2002","journal-title":"IEEE Trans. Acoust. Speech Signal Proc."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"806","DOI":"10.1109\/TASSP.1985.1164649","article-title":"On spatial smoothing for direction-of-arrival estimation of coherent signals","volume":"33","author":"Shan","year":"1985","journal-title":"IEEE Trans. Acoust. Speech Signal Proc."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1109\/29.17496","article-title":"Forward\/backward spatial smoothing techniques for coherent signal identification","volume":"37","author":"Pillai","year":"1989","journal-title":"IEEE Trans. Acoust. Speech Signal Proc."},{"key":"ref_20","unstructured":"Trees, H.L.V. (2002). Optimum Array Processing: Part IV of Detection, Estimation and Modulation Theory, John Wiley & Sons."},{"key":"ref_21","unstructured":"Haykin, S., Justice, J.H., Owsley, N.L., Yen, J.L., and Kak, A.C. (1997, January 21\u201323). Array Signal Processing. Proceedings of the IEEE Signal Processing Workshop on Higher-order Statistics, Banff, AB, Canada."},{"key":"ref_22","unstructured":"Zhang, X., Lv, W., Shi, Y., Zhao, R., and Xu, D. (2007, January 16\u201317). A Novel DOA Estimation Algorithm Based on Eigen Space. Proceedings of the International Symposium on Microwave, Hangzhou, China."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1109\/TVT.2008.924975","article-title":"Statistical NLOS Identification Based on AOA, TOA, and Signal Strength","volume":"58","author":"Yu","year":"2009","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Hastie, T., Tibshirani, R., and Friedman, J. (2009). Ensemble Learning. The Elements of Statistical Learning, Springer.","DOI":"10.1007\/978-0-387-84858-7_16"},{"key":"ref_25","unstructured":"Bishop, C.M. (2006). Pattern Recognition and Machine Learning (Information Science and Statistics), Springer."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2522","DOI":"10.3390\/s17112522","article-title":"Indoor Multipath Assisted Angle of Arrival Localization","volume":"17","author":"Stijn","year":"2017","journal-title":"Sensors"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/11\/2482\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:54:52Z","timestamp":1760187292000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/11\/2482"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,5,30]]},"references-count":26,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2019,6]]}},"alternative-id":["s19112482"],"URL":"https:\/\/doi.org\/10.3390\/s19112482","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,5,30]]}}}