{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T00:59:36Z","timestamp":1774400376649,"version":"3.50.1"},"reference-count":69,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2017,11,2]],"date-time":"2017-11-02T00:00:00Z","timestamp":1509580800000},"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>Indoor radio frequency positioning systems enable a broad range of location aware applications. However, the localization accuracy is often impaired by Non-Line-Of-Sight (NLOS) connections and indoor multipath effects. An interesting evolution in widely deployed communication systems is the transition to multi-antenna devices with beamforming capabilities. These properties form an opportunity for localization methods based on Angle of Arrival (AoA) estimation. This work investigates how multipath propagation can be exploited to enhance the accuracy of AoA localization systems. The presented multipath assisted method resembles a fingerprinting approach, matching an AoA measurement vector to a set of reference vectors. However, reference data is not generated by labor intensive site surveying. Instead, a ray tracer is used, relying on a-priori known floor plan information. The resulting algorithm requires only one fixed receiving antenna array to determine the position of a mobile transmitter in a room. The approach is experimentally evaluated in LOS and NLOS conditions, providing insights in the accuracy and robustness. The measurements are performed in various indoor environments with different hardware configurations. This leads to the conclusion that the proposed system yields a considerable accuracy improvement over common narrowband AoA positioning methods, as well as a reduction of setup efforts in comparison to conventional fingerprinting systems.<\/jats:p>","DOI":"10.3390\/s17112522","type":"journal-article","created":{"date-parts":[[2017,11,3]],"date-time":"2017-11-03T04:43:13Z","timestamp":1509684193000},"page":"2522","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":72,"title":["Indoor Multipath Assisted Angle of Arrival Localization"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2672-2998","authenticated-orcid":false,"given":"Stijn","family":"Wielandt","sequence":"first","affiliation":[{"name":"Dramco Research Group, Faculty of Engineering Technology, Electronics, KU Leuven, Gebroeders De Smetstraat 1, 9000 Ghent, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lieven","family":"Strycker","sequence":"additional","affiliation":[{"name":"Dramco Research Group, Faculty of Engineering Technology, Electronics, KU Leuven, Gebroeders De Smetstraat 1, 9000 Ghent, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,11,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1038\/sj.jea.7500165","article-title":"The National Human Activity Pattern Survey (NHAPS): A resource for assessing exposure to environmental pollutants","volume":"11","author":"Klepeis","year":"2001","journal-title":"J. Expo. Anal. Environ. Epidemiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1080\/17489725.2013.870419","article-title":"Editorial","volume":"8","author":"Li","year":"2014","journal-title":"J. Locat. Based Serv."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Kolodziej, K.W., and Hjelm, J. (2006). Local Positioning Systems: LBS Applications and Services, CRC Press.","DOI":"10.1201\/9780849333491"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Kupper, A. (2005). Location-Based Services: Fundamentals and Operation, John Wiley & Sons.","DOI":"10.1002\/0470092335"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1067","DOI":"10.1109\/TSMCC.2007.905750","article-title":"Survey of wireless indoor positioning techniques and systems","volume":"37","author":"Liu","year":"2007","journal-title":"IEEE Trans. Syst. Man Cybern. Part C Appl. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Mautz, R. (2009, January 19). The challenges of indoor environments and specification on some alternative positioning systems. Proceedings of the 2009 6th Workshop on Positioning, Navigation and Communication, Hannover, Germany.","DOI":"10.1109\/WPNC.2009.4907800"},{"key":"ref_7","unstructured":"Meissner, P. (2014). Multipath-Assisted Indoor Positioning. [Ph.D. Thesis, Graz University of Technology]."},{"key":"ref_8","unstructured":"Bensky, A. (2008). Wireless Positioning Technologies and Applications, Artech House."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Sahinoglu, Z., Gezici, S., and Guvenc, I. (2008). Ultra-Wideband Positioning Systems, Cambridge University Press.","DOI":"10.1017\/CBO9780511541056"},{"key":"ref_10","unstructured":"Munoz, D., Lara, F.B., Vargas, C., and Caldera, R.E. (2009). Position Location Techniques and Applications, Academic Press."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"He, T., Huang, C., Blum, B.M., Stankovic, J.A., and Abdelzaher, T. (2003, January 14\u201319). Range-free localization schemes for large scale sensor networks. Proceedings of the 9th Annual International Conference on Mobile Computing and Networking, San Diego, CA, USA.","DOI":"10.1145\/938985.938995"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1109\/MSP.2005.1458275","article-title":"Network-based wireless location: Challenges faced in developing techniques for accurate wireless location information","volume":"22","author":"Sayed","year":"2005","journal-title":"IEEE Signal Proc. Mag."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Barclay, L.W. (2003). Propagation of Radiowaves, Institution of Engineering and Technology. [2nd ed.].","DOI":"10.1049\/PBEW502E"},{"key":"ref_14","unstructured":"Hoefel, R.P.F. (2013, January 27\u201330). Ieee 802.11ac: A performance assessment of single-user transmit beamforming and multi-user mimo transceiver architectures. Proceedings of the Tenth International Symposium on Wireless Communication Systems (ISWCS 2013), Ilmenau, Germany."},{"key":"ref_15","unstructured":"Molisch, A. (2011). Wireless Communications, John Wiley & Sons. [2nd ed.]."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1109\/MCOM.2014.6736761","article-title":"Massive mimo for next generation wireless systems","volume":"52","author":"Larsson","year":"2014","journal-title":"IEEE Commun. Mag."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"560","DOI":"10.1109\/TWC.2004.843040","article-title":"Nonline-of-sight error mitigation in mobile location","volume":"4","author":"Cong","year":"2005","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_18","unstructured":"Chen, P. (1999, January 21\u201324). A non-line-of-sight error mitigation algorithm in location estimation. Proceedings of the 1999 IEEE Wireless Communications and Networking Conference (Cat. No. 99TH8466), New Orleans, LA, USA."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Grosicki, E., Abed-Meriam, K., and Dehak, R. (2004, January 20\u201324). A novel method to fight the non-line-of-sight error in AoA measurements for mobile location. Proceedings of the 2004 IEEE International Conference on Communications (IEEE Cat. No. 04CH37577), Paris, France.","DOI":"10.1109\/ICC.2004.1313039"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2475","DOI":"10.1109\/TSP.2017.2666779","article-title":"Direct localization for massive MIMO","volume":"65","author":"Garcia","year":"2017","journal-title":"IEEE Trans. Signal Proc."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"3579","DOI":"10.1109\/TWC.2008.070373","article-title":"A novel algorithm for multipath fingerprinting in indoor WLAN environments","volume":"7","author":"Fang","year":"2008","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Meissner, P., Steiner, C., and Witrisal, K. (2010, January 11\u201312). UWB positioning with virtual anchors and floor plan information. Proceedings of the 2010 7th Workshop on Positioning, Navigation and Communication, Dresden, Germany.","DOI":"10.1109\/WPNC.2010.5650374"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Meissner, P., Gan, M., Mani, F., Leitinger, E., Fr\u00f6hle, M., Oestges, C., Zemen, T., and Witrisal, K. (2013, January 9\u201313). On the use of ray tracing for performance prediction of UWB indoor localization systems. Proceedings of the 2013 IEEE International Conference on Communications Workshops (ICC), Budapest, Hungary.","DOI":"10.1109\/ICCW.2013.6649203"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Meissner, P., Leitinger, E., Lafer, M., and Witrisal, K. (2014, January 10\u201314). Real-time demonstration of multipath-assisted indoor navigation and tracking (MINT). Proceedings of the 2014 IEEE International Conference on Communications Workshops (ICC), Sydney, Australia.","DOI":"10.1109\/ICCW.2014.6881187"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Kulmer, J., Leitinger, E., Meissner, P., Hinteregger, S., and Witrisal, K. (2016, January 28\u201330). Cooperative localization and tracking using multipath channel information. Proceedings of the International Conference on Localization and GNSS (ICL-GNSS), Barcelona, Spain.","DOI":"10.1109\/ICL-GNSS.2016.7533692"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Meissner, P., Gigl, T., and Witrisal, K. (2010, January 15\u201317). UWB sequential monte carlo positioning using virtual anchors. Proceedings of the 2010 International Conference on Indoor Positioning and Indoor Navigation, Zurich, Switzerland.","DOI":"10.1109\/IPIN.2010.5647797"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Van de Velde, S., and Steendam, H. (2012, January 13\u201315). CUPID algorithm for cooperative indoor multipath-aided localization. Proceedings of the 2012 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Sydney, Australia.","DOI":"10.1109\/IPIN.2012.6418912"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Van de Velde, S., Wymeersch, H., Meissner, P., Witrisal, K., and Steendam, H. (2012, January 1\u20134). Cooperative multipath-aided indoor localization. Proceedings of the 2012 IEEE Wireless Communications and Networking Conference (WCNC), Shanghai, China.","DOI":"10.1109\/WCNC.2012.6214339"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1109\/LCOMM.2009.081584","article-title":"Single-anchor indoor localization using a switched-beam antenna","volume":"13","author":"Giorgetti","year":"2009","journal-title":"IEEE Commun. Lett."},{"key":"ref_30","unstructured":"Maddio, S., Cidronali, A., Giorgetti, G., and Manes, G. (October, January 30). Calibration of a 2.45 ghz indoor direction of arrival system based on unknown antenna gain. Proceedings of the 7th European Radar Conference, Paris, France."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1183","DOI":"10.1109\/LAWP.2015.2498950","article-title":"Single-anchor indoor localization using espar antenna","volume":"15","author":"Rzymowski","year":"2016","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Ohtani, M., Iwai, H., and Sasaoka, H. (2013, January 5\u20138). Evaluation of terminal position estimation by position fingerprinting technique using array antenna. Proceedings of the 2013 Asia-Pacific Microwave Conference Proceedings (APMC), Seoul, Korea.","DOI":"10.1109\/APMC.2013.6695157"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Savic, V., and Larsson, E.G. (2015, January 6\u20139). Fingerprinting-based positioning in distributed massive MIMO systems. Proceedings of the 2015 IEEE 82nd Vehicular Technology Conference (VTC2015-Fall), Boston, MA, USA.","DOI":"10.1109\/VTCFall.2015.7390953"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1007\/s00779-010-0357-x","article-title":"EDIPS: An easy to deploy indoor positioning system to support loosely coupled mobile work","volume":"15","author":"Vera","year":"2011","journal-title":"Pers. Ubiquitous Comput."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"e17","DOI":"10.2196\/mhealth.2543","article-title":"Enhancing knowledge flow in a health care context: A mobile computing approach","volume":"2","author":"Oliveira","year":"2014","journal-title":"J. Med. Internet Res. mHealth uHealth"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Biswas, A., Mustaquim, S.M.S., Hasan, R., and Chakrabarty, A. (2017, January 19\u201321). An easily deployable system for indoor positioning using Wi-Fi network. Proceedings of the 2017 1st International Conference on Next Generation Computing Applications (NextComp), Reduit, Mauritius.","DOI":"10.1109\/NEXTCOMP.2017.8016190"},{"key":"ref_37","unstructured":"Chen, Z., Gokeda, G., and Yu, Y. (2010). Introduction to Direction-of-Arrival Estimation, Artech House."},{"key":"ref_38","unstructured":"Van Trees, H.L. (2005). Optimum Array Processing, John Wiley & Sons."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Wielandt, S., Goemaere, J.P., de Strycker, L., and Nauwelaers, B. (2015, January 13\u201316). Performance simulations of a 2.4 ghz indoor angle of arrival system for multipath components. Proceedings of the 2015 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Banff, AB, Canada.","DOI":"10.1109\/IPIN.2015.7346787"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1195","DOI":"10.1109\/5.622504","article-title":"Application of antenna arrays to mobile communications. ii. Beam-forming and direction-of-arrival considerations","volume":"85","author":"Godara","year":"1997","journal-title":"Proc Inst. Electr. Electron. Eng."},{"key":"ref_41","unstructured":"Haykin, S. (1996). Adaptive Filter Theory, Prentice Hall."},{"key":"ref_42","unstructured":"Stoica, P., and Moses, R. (2005). Spectral Analysis of Signals, Prentice Hall."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1049\/ecej:19950507","article-title":"Propagation modelling for indoor wireless communication","volume":"7","author":"Tam","year":"1995","journal-title":"Electron. Commun. Eng. J."},{"key":"ref_44","first-page":"43","article-title":"Implementation of 3-D ray tracing propagation model for indoor wireless communication","volume":"4","author":"Sidhu","year":"2012","journal-title":"Int. J. Electron. Eng."},{"key":"ref_45","first-page":"15","article-title":"Ray tracing algorithm for specific indoor propagation modeling","volume":"3","author":"Juwita","year":"2011","journal-title":"J. Telecommun. Electron. Comput. Eng."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"397","DOI":"10.2528\/PIER11041602","article-title":"A quasi three-dimensional ray tracing method based on the virtual source tree in urban microcellular environments","volume":"118","author":"Liu","year":"2011","journal-title":"Prog. Electromagn. Res."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"662","DOI":"10.1109\/22.989951","article-title":"Propagation prediction models for wireless communication systems","volume":"50","author":"Iskander","year":"2002","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_48","unstructured":"Yun, Z., and Iskander, M.F. (2005, January 3\u20137). Characterization of angle of arrival based on ray-tracing for an indoor wireless communications environment. Proceedings of the IEEE\/ACES International Conference on Wireless Communications and Applied Computational Electromagnetics, Honolulu, HI, USA."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Gan, M., Meissner, P., Mani, F., Leitinger, E., Frohle, M., Oestges, C., Witrisal, K., and Zemen, T. (2014, January 6\u20139). Low-complexity sub-band divided ray tracing for uwb indoor channels. Proceedings of the 2014 IEEE Wireless Communications and Networking Conference (WCNC), Istanbul, Turkey.","DOI":"10.1109\/WCNC.2014.6951985"},{"key":"ref_50","first-page":"324758","article-title":"Validation of three-dimensional ray-tracing algorithm for indoor wirless propagations","volume":"2011","author":"Salem","year":"2011","journal-title":"Int. Sch. Res. Not. Commun. Netw."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Sarkar, T.K., Wicks, M.C., Salazar-Palma, M., and Bonneau, R.J. (2003). Smart Antennas, John Wiley & Sons.","DOI":"10.1002\/0471722839"},{"key":"ref_52","unstructured":"Saunders, S.R., and Aragon-Zavala, A. (2007). Antennas and Propagation for Wireless Communication Systems, John Wiley & Sons. [2nd ed.]."},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Seybold, J. (2005). Introduction to RF Propagation, John Wiley & Sons.","DOI":"10.1002\/0471743690"},{"key":"ref_54","unstructured":"Popovic, Z.B., and Popovic, B.D. (2000). Introductory Electromagnetics, Prentice Hall."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Shen, Y., Law, C.L., and Dou, W. (2008, January 10\u201312). Ultra-wideband measurement of the dielectric constant and loss tangent of concrete slabs. Proceedings of the 2008 China-Japan Joint Microwave Conference, Shanghai, China.","DOI":"10.1109\/CJMW.2008.4772488"},{"key":"ref_56","unstructured":"Safaai-Jazi, A., Riad, S.M., Muqaibel, A., and Bayram, A. (2002). Ultra-Wideband Propagation Measurements and Channel Modeling, Virginia Polytechnic Institute and State University. Technical Report."},{"key":"ref_57","first-page":"254","article-title":"A note on a simple transmission formula","volume":"34","author":"Friis","year":"1946","journal-title":"Proc. Inst. Radio Eng."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1002\/mop.1238","article-title":"Frequency dependence of dielectric constant of construction materials in microwave and millimeter-wave bands","volume":"30","author":"Cuinas","year":"2001","journal-title":"Microw. Opt. Technol. Lett."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1023\/A:1013886209664","article-title":"Permittivity and conductivity measurements of building materials at 5.8 GHz and 41.5 GHz","volume":"20","year":"2002","journal-title":"Wirel. Pers. Commun."},{"key":"ref_60","first-page":"43","article-title":"A ray tracing method for radio wave propagation prediction on selected locations of sun-u campus","volume":"9","author":"Lim","year":"2012","journal-title":"Sunway Acad. J."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"177","DOI":"10.2528\/PIERB10091004","article-title":"Measured complex permittivity of walls with different hydration levels and the effect on power estimation of twri target returns","volume":"30","author":"Thajudeen","year":"2011","journal-title":"Prog. Electromagn. Res. B"},{"key":"ref_62","unstructured":"Groot, E.D., Bose, T., Cooper, C., and Kruse, M. (2014, January 6\u20138). Remote transmitter tracking with raytraced fingerprint database. Proceedings of the 2014 IEEE Military Communications Conference, Baltimore, MD, USA."},{"key":"ref_63","unstructured":"Wielandt, S., Goemaere, J.P., and de Strycker, L. (2016, January 4\u20137). 2.4 GHz synthetic linear antenna array for indoor propagation measurements in static environments. Proceedings of the 2016 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Alcal\u00e1 de Henares, Spain."},{"key":"ref_64","unstructured":"Emerson & Cuming Anechoic Chambers NV (2010). Datasheet ECCOSORB VHP-NRL EB-100 Very High Performance Broadband Pyramidal Absorber, E&C Anechoic Chambers NV."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1109\/TSP.2012.2222395","article-title":"Single-site emitter localization via multipath fingerprinting","volume":"61","author":"Kupershtein","year":"2013","journal-title":"IEEE Trans. Signal Proc."},{"key":"ref_66","doi-asserted-by":"crossref","unstructured":"Tayebi, A., Gomez, J., de Adana, F.S., and Gutierrez, O. (2009, January 14\u201318). Ray-tracing application to mobile localization in multipath indoor environments. Proceedings of the 2009 International Conference on Electromagnetics in Advanced Applications, Torino, Italy.","DOI":"10.1109\/ICEAA.2009.5297405"},{"key":"ref_67","doi-asserted-by":"crossref","unstructured":"Hanssens, B., Plets, D., Tanghe, E., Oestges, C., Gaillot, D.P., Li\u00e9nard, M., Martens, L., and Joseph, W. (July, January 26). An indoor localization technique based on ultra-wideband aod\/aoa\/toa estimation. Proceedings of the In 2016 IEEE International Symposium on Antennas and Propagation (APSURSI), Fajardo, Puerto Rico.","DOI":"10.1109\/APS.2016.7696429"},{"key":"ref_68","doi-asserted-by":"crossref","unstructured":"Chen, C.M., Volskiy, V., Chiumento, A., van der Perre, L., Vandenbosch, G.A.E., and Pollin, S. (2016, January 4\u20138). Exploration of user separation capabilities by distributed large antenna arrays. Proceedings of the 2016 IEEE Globecom Workshops (GC Wkshps), Washington, DC, USA.","DOI":"10.1109\/GLOCOMW.2016.7848903"},{"key":"ref_69","doi-asserted-by":"crossref","unstructured":"Azzouzi, S., Cremer, M., Dettmar, U., Kronberger, R., and Knie, T. (2011, January 12\u201314). New measurement results for the localization of uhf rfid transponders using an angle of arrival (AoA) approach. Proceedings of the 2011 IEEE International Conference on RFID, Orlando, FL, USA.","DOI":"10.1109\/RFID.2011.5764607"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/11\/2522\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:49:12Z","timestamp":1760208552000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/11\/2522"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,11,2]]},"references-count":69,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2017,11]]}},"alternative-id":["s17112522"],"URL":"https:\/\/doi.org\/10.3390\/s17112522","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,11,2]]}}}