XIE et al:SYNCHRONIZE INERTIAL READINGS FROM MULTIPLE MOBILE DEVICES IN SPATIAL DIMENSION 2159 [9]B.Barshan and H.Durrant-Whyte,"Inertial navigation systems Lei Xie received the B.S.and Ph.D.degrees in for mobile robots,"IEEE Trans.Robot.Automat..vol.11,no.3. computer science from Nanjing University.China. Pp.328-342,Jun.1995. in 2004 and 2010,respectively.He is currently [10]H.-J.Lee and S.Jung,"Gyro sensor drift compensation by Kalman filter an Associate Professor with the Department of to control a mobile inverted pendulum robot system,"in Proc./EEE Computer Science and Technology.Nanjing Uni- ICT,Feb.2009,Pp.1-6. versity.He has published over 60 papers in the [11]J.Marins,X.Yun,E.Bachmann.R.Mcghee,and M.Zyda,"An IEEE/ACM TRANSACTIONS ON NETWORKING, extended Kalman filter for quaternion-based orientation estimation the IEEE TRANSACTIONS ON MOBILE COMPUT- using MARG sensors,"in Proc.IEEE/RSJ IROS,Oct./Nov.2001 ING,the IEEE TRANSACTIONS ON PARALLEL AND Pp.2003-2011. DISTRIBUTED SYSTEMS.ACM Transactions on [12]J.O.Woodman."An introduction to inertial navigation,"Dept.Comput. Sensor Nerworks.ACM MobiCom.ACM UbiComp Lab.,Univ.Cambridge,Cambridge,U.K.,Tech.Rep.UCAM-CL- ACM MobiHoc.IEEE INFOCOM,IEEE ICNP,and IEEE ICDCS TR696.2007. [13]S.Madgwick.A.J.L.Harrison.and R.Vaidyanathan,"Estimation of IMU and MARG orientation using a gradient descent algorithm,"in Qingliang Cai received the B.S.degree in software Proc.IEEE ICORR,Jun /Jul.2011.pp.1-7. engineering from Suzhou University.China,in 2014. [14]M.Gowda et al,"Bringing loT to sports analytics,"in Proc. and the M.S.degree from the Department of Com- 14th USENIX Symp.Netw.Syst.Design Implement.(NSDI),2017, Pp.499-513 puter Science and Technology,Nanjing University. in 2017.His research interests include wearable [15]J.Metge,R.Megret,A.Giremus,Y.Berthoumieu,and T.Decamps, computing. "Calibration of an inertial-magnetic measurement unit without extemal equipment,in the presence of dynamic magnetic disturbances,"Meas. Sci.Technol..,vol.25.no.12,p.125106.2014. [16]A.Baak,T.Helten,M.Muiller,G.Pons-Moll,B.Rosenhahn,and H.Seidel,"Analyzing and evaluating markerless motion tracking using inertial sensors,"in Proc.IIth Eur.Conf.Trends Topics Comput. is.(ECCV),vol.1,2012.Pp.139-152. [17]T.von Marcard,B.Rosenhahn,M.J.Black,and G.Pons-Moll,"Sparse Alex X.Liu received the Ph.D.degree in computer inertial poser:Automatic 3D human pose estimation from sparse IMUs," science from The University of Texas at Austin in Proc.EUROGRAPHICS,2017,pp.499-513. in 2006.His research interests focus on networking [18]S.Guha er al.,"Auto Witness:Locating and tracking stolen property and security.He received the IEEE IFIP William while tolerating GPS and radio outages,"in Proc.ACM SenSys,2010, C.Carter Award in 2004,the National Science Pp.29-42. Foundation CAREER Award in 2009.and the Michi- [19]PMohan,V.N.Padmanabhan,and R.Ramjee,"Nericell:Using mobile gan State University Withrow Distinguished Scholar smartphones for rich monitoring of road and traffic conditions,"in Proc. Award in 2011.He received Best Paper Awards from ACM SenSys,2008,pp.357-358. ICNP-2012.SRDS-2012.and LISA-2010.He is an [20]N.Roy.H.Wang.and R.R.Choudhury."I am a smartphone and Associate Editor of the IEEE/ACM TRANSACTIONS I can tell my user's walking direction,"in Proc.MobiSys,2014, ON NETWORKING,an Editor of the IEEE TRANS- 211 Shen Chen.P.Zhans.T.Moscibroda.and Y.Zhans. ACTIONS ON DEPENDABLE AND SECURE COMPUTING,and an Area Editor of Computer Communications. "Walkie-Markie:Indoor pathway mapping made easy,"in Proc.USENIX NSDL,2013,Pp.85-98. [22]H.Wang er al,"No need to war-drive:Unsupervised indoor localiza- Wei Wang received the M.S.degree from the ESE tion."in Proc.ACM MobiSys.2012.pp.197-210. Department,Nanjing University,in 2000,and the [23]J.A.B.Link,P.Smith,N.Viol.and K.Wehrle."FootPath:Accurate Ph.D.degree from the ECE Department,National map-based indoor navigation using smartphones,"in Proc.IPIN,2011. University of Singapore,in 2008.He is currently 即1-8 an Associate Professor with the CS Department, [24]X.Zhu.Q.Li,and G.Chen."APT:Accurate outdoor pedestrian Nanjing University.His research interests are in tracking with smartphones,"in Proc.IEEE INFOCOM,Apr.2013. the area of wireless networks,including device-free 251Rpaudin and G.Lachapells."Maspeticfield based headine sensing.cellular network measurements,and soft- ware defined radio systems. estimation for pedestrian navigation environments,"in Proc.IPIN.2011 Pp.1-10. [26]S.-W.Lee,P.Jung.and S.-H.Song,"Hybrid indoor location tracking for pedestrian using a smartphone,"in Robot Intelligence Technology and Yafeng Yin received the B.E.degree in network Applications.Berlin,Germany:Springer,2013,pp.431-440. engineering from the Nanjing University of Science [27]S.Butterworth,"On the theory of filter amplifiers,"Wireless Engineer. and Technology in 2011,and the Ph.D.degree in vol.7,no.6,pp.536-541,1930. computer science from Nanjing University,China, [28]O.Rodrigues,"Des lois geometriques qui regissent les deplacements in 2017.She is currently an Assistant Professor d'un systeme solide dans I'espace,et de la variation des coordonnees with the Department of Computer Science and Tech- provenant de ces deplacements consideres independamment des causes nology,Nanjing University.Her research interests qui peuvent les produire,"J.Math.Pures Appl.,vol.5,pp.380-440, include human activity recognition,mobile sensing. 1840. and wearable computing. [29]J.Lester,B.Hannaford,and G.Borriello,"Are you with me?'-Using accelerometers to determine if two devices are carried by the same person,"in Proc.Pervasive Comput.(Pervasive),2004,pp.33-50. [30]C.T.Cornelius and D.F.Kotz,"Recognizing whether sensors are on Sanglu Lu received the B.S.,M.S.,and Ph.D. the same body,"Pervasive Mobile Comput..vol.8,no.6,pp.822-836, degrees in computer science from Nanjing Univer- 2012. sity,China,in 1992,1995.and 1997.respectively. [31]R.Faragher,"Understanding the basis of the Kalman filter via a simple She is currently a Professor with the Department and intuitive derivation,"IEEE Signal Process.Mag.,vol.29,no.5, of Computer Science and Technology,Nanjing Uni- pp.128-132.Sep.2012 [32](2013).Reading a IMU Without Kalman:The Complementary Filter. versity.Her research interests include distributed computing and pervasive computing. [Online].Available:http://www.pieter-jan.com/node/11 [33]Monsoon Solutions Inc.(2015).Monsoon Power Monsoon Power Monitor.[Online].Available:https://www.msoon.com/LabEquipment/ PowerMonitorXIE et al.: SYNCHRONIZE INERTIAL READINGS FROM MULTIPLE MOBILE DEVICES IN SPATIAL DIMENSION 2159 [9] B. Barshan and H. Durrant-Whyte, “Inertial navigation systems for mobile robots,” IEEE Trans. Robot. Automat., vol. 11, no. 3, pp. 328–342, Jun. 1995. [10] H.-J. Lee and S. Jung, “Gyro sensor drift compensation by Kalman filter to control a mobile inverted pendulum robot system,” in Proc. IEEE ICIT, Feb. 2009, pp. 1–6. [11] J. Marins, X. Yun, E. Bachmann, R. Mcghee, and M. Zyda, “An extended Kalman filter for quaternion-based orientation estimation using MARG sensors,” in Proc. IEEE/RSJ IROS, Oct./Nov. 2001, pp. 2003–2011. [12] J. O. Woodman, “An introduction to inertial navigation,” Dept. Comput. Lab., Univ. Cambridge, Cambridge, U.K., Tech. Rep. UCAM-CL￾TR696, 2007. [13] S. Madgwick, A. J. L. Harrison, and R. Vaidyanathan, “Estimation of IMU and MARG orientation using a gradient descent algorithm,” in Proc. IEEE ICORR, Jun./Jul. 2011, pp. 1–7. [14] M. Gowda et al., “Bringing IoT to sports analytics,” in Proc. 14th USENIX Symp. Netw. Syst. Design Implement. (NSDI), 2017, pp. 499–513. [15] J. Metge, R. Mégret, A. Giremus, Y. Berthoumieu, and T. Décamps, “Calibration of an inertial-magnetic measurement unit without external equipment, in the presence of dynamic magnetic disturbances,” Meas. Sci. Technol., vol. 25, no. 12, p. 125106, 2014. [16] A. Baak, T. Helten, M. Müller, G. Pons-Moll, B. Rosenhahn, and H. Seidel, “Analyzing and evaluating markerless motion tracking using inertial sensors,” in Proc. 11th Eur. Conf. Trends Topics Comput. Vis. (ECCV), vol. 1, 2012, pp. 139–152. [17] T. von Marcard, B. Rosenhahn, M. J. Black, and G. Pons-Moll, “Sparse inertial poser: Automatic 3D human pose estimation from sparse IMUs,” in Proc. EUROGRAPHICS, 2017, pp. 499–513. [18] S. Guha et al., “AutoWitness: Locating and tracking stolen property while tolerating GPS and radio outages,” in Proc. ACM SenSys, 2010, pp. 29–42. [19] P. Mohan, V. N. Padmanabhan, and R. Ramjee, “Nericell: Using mobile smartphones for rich monitoring of road and traffic conditions,” in Proc. ACM SenSys, 2008, pp. 357–358. [20] N. Roy, H. Wang, and R. R. Choudhury, “I am a smartphone and I can tell my user’s walking direction,” in Proc. MobiSys, 2014, pp. 329–342. [21] G. Shen, Z. Chen, P. Zhang, T. Moscibroda, and Y. Zhang, “Walkie-Markie: Indoor pathway mapping made easy,” in Proc. USENIX NSDI, 2013, pp. 85–98. [22] H. Wang et al., “No need to war-drive: Unsupervised indoor localiza￾tion,” in Proc. ACM MobiSys, 2012, pp. 197–210. [23] J. A. B. Link, P. Smith, N. Viol, and K. Wehrle, “FootPath: Accurate map-based indoor navigation using smartphones,” in Proc. IPIN, 2011, pp. 1–8. [24] X. Zhu, Q. Li, and G. Chen, “APT: Accurate outdoor pedestrian tracking with smartphones,” in Proc. IEEE INFOCOM, Apr. 2013, pp. 2508–2516. [25] M. Afzal, V. Renaudin, and G. Lachapelle, “Magneticfield based heading estimation for pedestrian navigation environments,” in Proc. IPIN, 2011, pp. 1–10. [26] S.-W. Lee, P. Jung, and S.-H. Song, “Hybrid indoor location tracking for pedestrian using a smartphone,” in Robot Intelligence Technology and Applications. Berlin, Germany: Springer, 2013, pp. 431–440. [27] S. Butterworth, “On the theory of filter amplifiers,” Wireless Engineer, vol. 7, no. 6, pp. 536–541, 1930. [28] O. Rodrigues, “Des lois géométriques qui régissent les déplacements d’un systéme solide dans l’espace, et de la variation des coordonnées provenant de ces déplacements considérés indépendamment des causes qui peuvent les produire,” J. Math. Pures Appl., vol. 5, pp. 380–440, 1840. [29] J. Lester, B. Hannaford, and G. Borriello, “‘Are you with me?’—Using accelerometers to determine if two devices are carried by the same person,” in Proc. Pervasive Comput. (Pervasive), 2004, pp. 33–50. [30] C. T. Cornelius and D. F. Kotz, “Recognizing whether sensors are on the same body,” Pervasive Mobile Comput., vol. 8, no. 6, pp. 822–836, 2012. [31] R. Faragher, “Understanding the basis of the Kalman filter via a simple and intuitive derivation,” IEEE Signal Process. Mag., vol. 29, no. 5, pp. 128–132, Sep. 2012. [32] (2013). Reading a IMU Without Kalman: The Complementary Filter. [Online]. Available: http://www.pieter-jan.com/node/11 [33] Monsoon Solutions Inc. (2015). Monsoon Power Monsoon Power Monitor. [Online]. Available: https://www.msoon.com/LabEquipment/ PowerMonitor Lei Xie received the B.S. and Ph.D. degrees in computer science from Nanjing University, China, in 2004 and 2010, respectively. He is currently an Associate Professor with the Department of Computer Science and Technology, Nanjing Uni￾versity. He has published over 60 papers in the IEEE/ACM TRANSACTIONS ON NETWORKING, the IEEE TRANSACTIONS ON MOBILE COMPUT￾ING, the IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, ACM Transactions on Sensor Networks, ACM MobiCom, ACM UbiComp, ACM MobiHoc, IEEE INFOCOM, IEEE ICNP, and IEEE ICDCS. Qingliang Cai received the B.S. degree in software engineering from Suzhou University, China, in 2014, and the M.S. degree from the Department of Com￾puter Science and Technology, Nanjing University, in 2017. His research interests include wearable computing. Alex X. Liu received the Ph.D. degree in computer science from The University of Texas at Austin in 2006. His research interests focus on networking and security. He received the IEEE & IFIP William C. Carter Award in 2004, the National Science Foundation CAREER Award in 2009, and the Michi￾gan State University Withrow Distinguished Scholar Award in 2011. He received Best Paper Awards from ICNP-2012, SRDS-2012, and LISA-2010. He is an Associate Editor of the IEEE/ACM TRANSACTIONS ON NETWORKING, an Editor of the IEEE TRANS￾ACTIONS ON DEPENDABLE AND SECURE COMPUTING, and an Area Editor of Computer Communications. Wei Wang received the M.S. degree from the ESE Department, Nanjing University, in 2000, and the Ph.D. degree from the ECE Department, National University of Singapore, in 2008. He is currently an Associate Professor with the CS Department, Nanjing University. His research interests are in the area of wireless networks, including device-free sensing, cellular network measurements, and soft￾ware defined radio systems. Yafeng Yin received the B.E. degree in network engineering from the Nanjing University of Science and Technology in 2011, and the Ph.D. degree in computer science from Nanjing University, China, in 2017. She is currently an Assistant Professor with the Department of Computer Science and Tech￾nology, Nanjing University. Her research interests include human activity recognition, mobile sensing, and wearable computing. Sanglu Lu received the B.S., M.S., and Ph.D. degrees in computer science from Nanjing Univer￾sity, China, in 1992, 1995, and 1997, respectively. She is currently a Professor with the Department of Computer Science and Technology, Nanjing Uni￾versity. Her research interests include distributed computing and pervasive computing