{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,15]],"date-time":"2026-03-15T03:29:40Z","timestamp":1773545380737,"version":"3.50.1"},"reference-count":57,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T00:00:00Z","timestamp":1649808000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004955","name":"Austrian Research Promotion Agency","doi-asserted-by":"publisher","award":["879691"],"award-info":[{"award-number":["879691"]}],"id":[{"id":"10.13039\/501100004955","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Blue force tracking represents an essential task in the field of military applications. A blue force tracking system provides the location information of their own forces on a map to commanders. For the command post, this results in more efficient operation control with increasing safety. In underground structures (e.g., tunnels or subways), the localisation is challenging due to the lack of GNSS signals. This paper presents a localisation system for military or emergency forces tailored to usage in complex underground structures. In a particle filter, position changes from a dual foot-mounted INS are fused with opportunistic UWB ranges and data from a 3D tunnel model to derive position information. A concept to deal with the absence of UWB infrastructure or 3D tunnel models is illustrated. Recurrent neural network methodologies are applied to cope with different motion types of the operators. The evaluation of the positioning algorithm took place in a street tunnel. If a fully installed infrastructure was available, positioning errors under one metre were reached. The results also showed that the INS can bridge UWB outages. A particle-filter-based approach to UWB anchor mapping is presented, and the first simulation results showed its viability.<\/jats:p>","DOI":"10.3390\/s22082982","type":"journal-article","created":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T23:07:16Z","timestamp":1649891236000},"page":"2982","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["NIKE BLUETRACK: Blue Force Tracking in GNSS-Denied Environments Based on the Fusion of UWB, IMUs and 3D Models"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7576-9760","authenticated-orcid":false,"given":"Karin","family":"Mascher","sequence":"first","affiliation":[{"name":"TU Graz, Working Group Navigation, Institute of Geodesy, 8010 Graz, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Markus","family":"Watzko","sequence":"additional","affiliation":[{"name":"TU Graz, Working Group Navigation, Institute of Geodesy, 8010 Graz, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8723-6352","authenticated-orcid":false,"given":"Axel","family":"Koppert","sequence":"additional","affiliation":[{"name":"OHB Digital Solutions GmbH, 8044 Graz, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Julian","family":"Eder","sequence":"additional","affiliation":[{"name":"IL\u2014Ingenieurb\u00fcro Laabmayr & Partner ZT GmbH, 5020 Salzburg, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Hofer","sequence":"additional","affiliation":[{"name":"Theresian Military Academy, Institute for Advanced Officer Training, 2700 Wiener Neustadt, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manfred","family":"Wieser","sequence":"additional","affiliation":[{"name":"TU Graz, Working Group Navigation, Institute of Geodesy, 8010 Graz, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,13]]},"reference":[{"key":"ref_1","first-page":"126","article-title":"Die Rolle von Virtual Reality in der Bew\u00e4ltigung milit\u00e4rischer Eins\u00e4tze unter Tage","volume":"6","author":"Hofer","year":"2020","journal-title":"AGIT\u2014J. Angew. Geoinform."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s00501-019-00915-9","article-title":"Coping with Complexity. The Development of Comprehensive SubSurface Training Standards from a Military Perspective","volume":"Volume 164","author":"Hofer","year":"2019","journal-title":"BHM Berg- und H\u00fcttenm\u00e4nnische Monatshefte"},{"key":"ref_3","first-page":"219","article-title":"Innovation and Intellectual Property Rights","volume":"Volume 1","author":"Haberfeld","year":"2009","journal-title":"A New Understanding of Terrorism"},{"key":"ref_4","unstructured":"(2022, January 12). Wiener Linien\u2014U-Bahn 2001 bis 2019. Available online: https:\/\/www.wien.gv.at\/statistik\/verkehr-wohnen\/tabellen\/u-bahn-zr.html."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1109\/MWC.2011.5751291","article-title":"Accurate and reliable soldier and first responder indoor positioning: Multisensor systems and cooperative localization","volume":"18","author":"Rantakokko","year":"2011","journal-title":"IEEE Wirel. Commun."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Kim Geok, T., Zar Aung, K., Sandar Aung, M., Thu Soe, M., Abdaziz, A., Pao Liew, C., Hossain, F., Tso, C.P., and Yong, W.H. (2021). Review of Indoor Positioning: Radio Wave Technology. Appl. Sci., 11.","DOI":"10.3390\/app11010279"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"26941","DOI":"10.1109\/ACCESS.2020.2968958","article-title":"An Improved Vision-Based Indoor Positioning Method","volume":"8","author":"Yang","year":"2020","journal-title":"IEEE Access"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Ren, M., Pan, K., Liu, Y., Guo, H., Zhang, X., and Wang, P. (2016). A Novel Pedestrian Navigation Algorithm for a Foot-Mounted Inertial-Sensor-Based System. Sensors, 16.","DOI":"10.3390\/s16010139"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Nilsson, J.O., Gupta, A.K., and H\u00e4ndel, P. (2014, January 27\u201330). Foot-mounted inertial navigation made easy. Proceedings of the 2014 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Busan, South Korea.","DOI":"10.1109\/IPIN.2014.7275464"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2657","DOI":"10.1109\/TBME.2010.2060723","article-title":"Zero-velocity detection\u2014An algorithm evaluation","volume":"57","author":"Skog","year":"2010","journal-title":"IEEE Trans. Bio-Med. Eng."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"957","DOI":"10.1109\/JSEN.2019.2944412","article-title":"Robust Data-Driven Zero-Velocity Detection for Foot-Mounted Inertial Navigation","volume":"20","author":"Wagstaff","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Prateek, G., Girisha, R., Hari, K., and H\u00e4ndel, P. (2013, January 29\u201331). Data Fusion of Dual Foot-Mounted INS to Reduce the Systematic Heading Drift. Proceedings of the International Conference on Intelligent Systems, Modelling and Simulation, Bangkok, Thailand.","DOI":"10.1109\/ISMS.2013.46"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Skog, I., Nilsson, J.O., Zachariah, D., and H\u00e4ndel, P. (2012, January 13\u201315). Fusing the information from two navigation systems using an upper bound on their maximum spatial separation. Proceedings of the 2012 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Sydney, Australia.","DOI":"10.1109\/IPIN.2012.6418862"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"4577","DOI":"10.1109\/JSEN.2019.2902422","article-title":"Data Fusion of Dual Foot-Mounted IMU for Pedestrian Navigation","volume":"19","author":"Niu","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4577","DOI":"10.1051\/e3sconf\/20199402007","article-title":"Error Analysis of PDR System Using Dual Foot-mounted IMU","volume":"94","author":"Lee","year":"2019","journal-title":"E3S Web Conf."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1186\/s43020-021-00053-z","article-title":"Distributed Kalman filter for UWB\/INS integrated pedestrian localization under colored measurement noise","volume":"2","author":"Xu","year":"2021","journal-title":"Satell. Navig."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Nilsson, M., Rantakokko, J., Skoglund, M.A., and Hendeby, G. (2014, January 27\u201330). Indoor positioning using multi-frequency RSS with foot-mounted INS. Proceedings of the 2014 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Busan, Korea.","DOI":"10.1109\/IPIN.2014.7275482"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Krach, B., and Robertson, P. (2008, January 27). Integration of Foot-Mounted Inertial Sensors into a Bayesian Location Estimation Framework. Proceedings of the 5th Workshop on Positioning, Navigation and Communication, Hannover, Germany.","DOI":"10.1109\/WPNC.2008.4510357"},{"key":"ref_19","unstructured":"Woodman, O. (2010). Pedestrian Localisation for Indoor Environments. [Ph.D. Thesis, University of Cambridge]. submitted."},{"key":"ref_20","first-page":"88:1","article-title":"Self-calibration and Collaborative Localization for UWB Positioning Systems: A Survey and Future Research Directions","volume":"54","author":"Ridolfi","year":"2021","journal-title":"ACM Comput. Surv."},{"key":"ref_21","unstructured":"Mart\u00ednez Almansa, C., Shule, W., Queralta, J.P., and Westerlund, T. (2020, January 2\u20134). Autocalibration of a Mobile UWB Localization System for Ad-Hoc Multi-Robot Deployments in GNSS-Denied Environments. Proceedings of the ICL-GNSS 2020 WiP Proceedings, Tampere, Finland."},{"key":"ref_22","unstructured":"(2022, January 31). MDEK1001 Development Kit. Available online: https:\/\/www.decawave.com\/product\/mdek1001-deployment-kit\/."},{"key":"ref_23","unstructured":"Pereira, J. (2021). Anchor Self-Calibrating Schemes for UWB based Indoor Localization. [Master\u2019s Thesis, Rochester Institute of Technology]. submitted."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Galov, A., and Moschevikin, A. (2014, January 27\u201330). Simultaneous localization and mapping in indoor positioning systems based on round trip time-of-flight measurements and inertial navigation. Proceedings of the 2014 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Busan, Korea.","DOI":"10.1109\/IPIN.2014.7275517"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"728","DOI":"10.26599\/TST.2018.9010102","article-title":"Anchor self-localization algorithm based on UWB ranging and inertial measurements","volume":"24","author":"Shi","year":"2019","journal-title":"Tsinghua Sci. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/j.inffus.2018.01.005","article-title":"Simultaneous calibration and navigation (SCAN) of multiple ultrasonic local positioning systems","volume":"45","author":"Gualda","year":"2019","journal-title":"Inf. Fusion"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Nilsson, J.O., Rantakokko, J., H\u00e4ndel, P., Skog, I., Ohlsson, M., and Hari, K. (2014, January 5\u20138). Accurate indoor positioning of firefighters using dual foot-mounted inertial sensors and inter-agent ranging. Proceedings of the Position Location and Navigation Symposium (PLANS), Monterey, CA, USA.","DOI":"10.1109\/PLANS.2014.6851424"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"14401","DOI":"10.1109\/JSEN.2020.2998815","article-title":"UWB\/INS Integrated Pedestrian Positioning for Robust Indoor Environments","volume":"20","author":"Zhang","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Han, Y., Wei, C., Li, R., Wang, J., and Yu, H. (2020). A Novel Cooperative Localization Method Based on IMU and UWB. Sensors, 20.","DOI":"10.3390\/s20020467"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.inffus.2019.10.009","article-title":"Cooperative positioning for emergency responders using self IMU and peer-to-peer radios measurements","volume":"56","author":"Liu","year":"2020","journal-title":"Inf. Fusion"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"6652","DOI":"10.1109\/JSEN.2020.2976097","article-title":"UWB-Based Localization System Aided With Inertial Sensor for Underground Coal Mine Applications","volume":"20","author":"Li","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Cao, Z., Liu, R., Yuen, C., Athukorala, A., Ng, B.K.K., Mathanraj, M., and Tan, U. (2021). Relative Localization of Mobile Robots with Multiple Ultra-WideBand Ranging Measurements. arXiv, Available online: https:\/\/arxiv.org\/abs\/2107.08842.","DOI":"10.1109\/IROS51168.2021.9636017"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Liu, R., He, Y., Yuen, C., Lau, B.P.L., Ali, R., Fu, W., and Cao, Z. (2021). Cost-effective Mapping of Mobile Robot Based on the Fusion of UWB and Short-range 2D LiDAR. arXiv, Available online: https:\/\/arxiv.org\/abs\/2106.03648.","DOI":"10.1109\/TMECH.2021.3087957"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Schlager, B., Stoll, D., Kr\u00f6sl, K., and Fuhrmann, A. (April, January 27). Tactical and Strategical Analysis in Virtual Geographical Environments. Proceedings of the 2021 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW), Lisbon, Portugal.","DOI":"10.1109\/VRW52623.2021.00193"},{"key":"ref_35","unstructured":"(2022, February 05). Xsens DOT User Manual, Document XD0502P, Revision D. Available online: https:\/\/www.xsens.com\/xsens-dot."},{"key":"ref_36","unstructured":"Hofer, P., Strau\u00df, C., Eder, J., Hager, L., Wenighofer, R., N\u00f6ger, M., and Fuchs, S. (2021). Das Fast Tunnel Modelling Tool f\u00fcr Untertagebauwerke, Wichmann Verlag."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Butler, H., Daly, M., Doyle, A., Gillies, S., Schaub, T., and Hagen, S. (2016). The GeoJSON Format, Internet Engineering Task Force (IETF). RFC 7946.","DOI":"10.17487\/RFC7946"},{"key":"ref_38","unstructured":"Mascher, K., and Wieser, M. (December, January 29). Foot-Mounted Inertial Navigation\u2014Implementation and Fusion Concept into a Bayesian Filtering Framework. Proceedings of the 2021 International Conference on Indoor Positioning and Indoor Navigation (IPIN), LLoret de Mar, Spain."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Noureldin, A. (2013). Fundamentals of Inertial Navigation, Satellite-based Positioning and their Integration, Springer.","DOI":"10.1007\/978-3-642-30466-8"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Hofmann-Wellenhof, B., Legat, K., and Wieser, M. (2003). Navigation: Principles of Positioning and Guidance, Springer Vienna. Springer eBook Collection.","DOI":"10.1007\/978-3-7091-6078-7"},{"key":"ref_41","first-page":"173","article-title":"Practical comparison of formulae for computing normal gravity at the observation point with emphasis on the territory of Slovakia","volume":"35","author":"Vajda","year":"2005","journal-title":"Contrib. Geophys. Geod."},{"key":"ref_42","unstructured":"Skog, I., Nilsson., J.-O., and H\u00e4ndel, P. (2013, January 28\u201331). Standing still with inertial navigation. Proceedings of the 2013 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Montbeliard-Belfort, France."},{"key":"ref_43","unstructured":"Chung, J., Gulcehre, C., Cho, K., and Bengio, Y. (2014). Empirical Evaluation of Gated Recurrent Neural Networks on Sequence Modeling. arXiv, Available online: https:\/\/arxiv.org\/abs\/1412.3555."},{"key":"ref_44","unstructured":"G\u00e9ron, A. (2019). Hands-on Machine Learning with Scikit-Learn, Keras, and TensorFlow: Concepts, Tools, and Techniques to Build Intelligent Systems, O\u2019Reilly. [2nd ed.]."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Cho, K., van Merrienboer, B., G\u00fcl\u00e7ehre, \u00c7., Bahdanau, D., Bougares, F., Schwenk, H., and Bengio, Y. (2014, January 25\u201329). Learning Phrase Representations using RNN Encoder-Decoder for Statistical Machine Translation. Proceedings of the 2014 Conference on Empirical Methods in Natural Language Processing\u2014EMNLP 2014, Doha, Qatar.","DOI":"10.3115\/v1\/D14-1179"},{"key":"ref_46","unstructured":"Abadi, M., Agarwal, A., Barham, P., Brevdo, E., Chen, Z., Citro, C., Corrado, G.S., Davis, A., Dean, J., and Devin, M. (2022, February 15). TensorFlow: Large-Scale Machine Learning on Heterogeneous Systems, 2015. Available online: tensorflow.org."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Wen, Q., Sun, L., Yang, F., Song, X., Gao, J., Wang, X., and Xu, H. (2021, January 19\u201327). Time Series Data Augmentation for Deep Learning: A Survey. Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, Montreal, QC, Canada.","DOI":"10.24963\/ijcai.2021\/631"},{"key":"ref_48","unstructured":"(2022, January 31). The Size and Quality of a Data Set. Available online: https:\/\/developers.google.com\/machine-learning\/data-prep\/construct\/collect\/data-size-quality."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Wagstaff, B., and Kelly, J. (2018, January 24\u201327). LSTM-Based Zero-Velocity Detection for Robust Inertial Navigation. Proceedings of the 2018 International Conference on Indoor Positioning and Indoor Navigation (IPIN), Nantes, France.","DOI":"10.1109\/IPIN.2018.8533770"},{"key":"ref_50","unstructured":"(2022, January 10). Using TensorFlow Lite to Speed up Predictions. Available online: https:\/\/micwurm.medium.com\/using-tensorflow-lite-to-speed-up-predictions-a3954886eb98."},{"key":"ref_51","unstructured":"Watzko, M. (2022). Integrated Navigation for Underground Pedestrian Positioning combining Inertial Measurements, Radio Signals and Map Information. [Master\u2019s Thesis, Graz University of Technology]. submitted."},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Elfring, J., Torta, E., and van de Molengraft, R. (2021). Particle Filters: A Hands-On Tutorial. Sensors, 21.","DOI":"10.3390\/s21020438"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1109\/MSP.2014.2330626","article-title":"Resampling Methods for Particle Filtering: Classification, implementation, and strategies","volume":"32","author":"Li","year":"2015","journal-title":"IEEE Signal Process. Mag."},{"key":"ref_54","unstructured":"Groves, P.D. (2008). Principles of GNSS, Inertial, and Multisensor Integrated Navigation Systems, Artech House. [2nd ed.]."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Liu, J., and West, M. (2001). Combined parameter and state estimation in simulation-based filtering. Sequential Monte Carlo Methods in Practice, Springer.","DOI":"10.1007\/978-1-4757-3437-9_10"},{"key":"ref_56","unstructured":"Hofer, P., Eder, J., and Strau\u00df, C. (2021). Decision Support within Complex Subterranean Operations. NATO Science and Technology Organization\u2014Meeting Proceedings Paper (STO-MP-MSG-184), NATO STO: North Atlantic Treaty Organization."},{"key":"ref_57","unstructured":"US Department of Defense (2022, January 17). JOINT MILITARY SYMBOLOGY: MIL-STD-2525C, Available online: https:\/\/worldwind.arc.nasa.gov\/milstd2525c\/Mil-STD-2525C.pdf."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/8\/2982\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:53:15Z","timestamp":1760136795000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/8\/2982"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,4,13]]},"references-count":57,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2022,4]]}},"alternative-id":["s22082982"],"URL":"https:\/\/doi.org\/10.3390\/s22082982","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,4,13]]}}}