[1] Leveson I. The economic value of GPS: preliminary assessment. Leveson Consulting. 2015, https://www.gps.gov/governance/advisory/meetings/2015-06/leveson.pdf

[2] Global Positioning System Standard Positioning Service Performance Standard. 4 ed, 2008

[3] Liu H, Darabi H, Banerjee P, Liu J. Survey of wireless indoor positioning techniques and systems. IEEE Transactions on Systems, Man and Cybernetics, Part C, Applications and Reviews, 2007, 37(6): 1067–1080

[4] Luo J, Fan L, Li H. Indoor positioning systems based on visible light communication: state of the art. IEEE Communications Surveys and Tutorials, 2017, 19(4): 2871–2893

[5] Zhang X, Duan J, Fu Y, Shi A. Theoretical accuracy analysis of indoor visible light communication positioning system based on received signal strength indicator. Journal of Lightwave Technology, 2014, 32(21): 4180–4186

[6] Kim Y, Hwang J, Lee J, YooM. Position estimation algorithm based on tracking of received light intensity for indoor visible light communication systems. In: Proceedings of International Conference on Ubiquitous & Future Networks. Dalian, China: IEEE, 2011, 131–134

[7] Jung S Y, Hann S, Park S, Park C S. Optical wireless indoor positioning system using light emitting diode ceiling lights. Microwave and Optical Technology Letters, 2012, 54(7): 1622–1626

[8] Ma R, Guo Q, Hu C, Xue J. An improved WiFi indoor positioning algorithm by weighted fusion. Sensors (Basel), 2015, 15(9): 21824–21843

[9] Taniuchi D, Liu X, Nakai D, Maekawa T. Spring model based collaborative indoor position estimation with neighbor mobile devices. IEEE Journal of Selected Topics in Signal Processing, 2015, 9(2): 268–277

[10] Lim J. Ubiquitous 3D positioning systems by led-based visible light communications. IEEEWireless Communications, 2015, 22(2): 80–85

[11] Gu W J, Aminikashani M, Deng P, Kavehrad M. Impact of multipath reflections on the performance of indoor visible light positioning systems. Journal of Lightwave Technology, 2016, 34(10): 2578–2587

[12] Rahaim M, Prince G B, Little T D C. State estimation and motion tracking for spatially diverse VLC networks. In: Proceedings of IEEE Globecom Workshops (GC Wkshps). Anaheim, CA, USA: IEEE, 2012, 1249–1253

[13] Jung S Y, Hann S, Park C S. TDOA-based optical wireless indoor localization using LED ceiling lamps. IEEE Transactions on Consumer Electronics, 2011, 57(4): 1592–1597

[14] De Angelis A, Moschitta A, Carbone P, Calderini M, Neri S, Borgna R, Peppucci M. Design and characterization of a portable ultrasonic indoor 3-D positioning system. IEEE Transactions on Instrumentation and Measurement, 2015, 64(10): 2616–2625

[15] Lindo A, Garcia E, Urena J, del Carmen Perez M, Hernandez A. Multiband waveform design for an ultrasonic indoor positioning system. IEEE Sensors Journal, 2015, 15(12): 7190–7199

[16] Wang T Q, Sekercioglu Y A, Neild A, Armstrong J. Position accuracy of time-of-arrival based ranging using visible light with application in indoor localization systems. Journal of Lightwave Technology, 2013, 31(20): 3302–3308

[17] Do T H, Yoo M. TDOA-based indoor positioning using visible light. Photonic Network Communications, 2014, 27(2): 80–88

[18] Panta K, Armstrong J. Indoor localization using white LEDs. Electronics Letters, 2012, 48(4): 228–230

[19] Arafa A, Jin X, Klukas R.Wireless indoor optical positioning with a differential photosensor. IEEE Photonics Technology Letters, 2012, 24(12): 1027–1029

[20] Arafa A, Jin X, Bergen M H, Klukas R, Holzman J F. Characterization of image receivers for optical wireless location technology. IEEE Photonics Technology Letters, 2015, 27(18): 1923–1926

[21] Bergen M H, Jin X, Guerrero D, Chaves H A L F, Fredeen N V, Holzman J F. Design and implementation of an optical receiver for angle-of-arrival-based positioning. Journal of Lightwave Technology, 2017, 35(18): 3877–3885

[22] Zhu B, Cheng J, Wang Y, Yan J, Wang J. Three-dimensional VLC positioning based on angle difference of arrival with arbitrary tilting angle of receiver. IEEE Journal on Selected Areas in Communications, 2018, 36(1): 8–22

[23] Yasir M, Ho S W, Vellambi B N. Indoor position tracking using multiple optical receivers. Journal of Lightwave Technology, 2016, 34(4): 1166–1176

[24] Wu J, Zhu J, Yu Z, Zhuge J. Three-dimensional temperature field compensation technology for large-scale ultrasonic positioning system. Transactions of the Institute of Measurement & Control, 2016, 39(12): 0142331216648375

[25] Zhao X, Xiao Z, Markham A, Trigoni N, Ren Y. Does BTLE measure up against WiFi? A comparison of indoor location performance. In: Proceedings of20th EuropeanWireless Conference on European Wireless. Barcelona, Spain: IEEE, 2014, 1–6

[26] Infsoft GmbH. Indoor Positioning, Tracking and Indoor Navigation with Wi-Fi. 2017, http://www.infsoft.com/technology/sensors/wifi,accessed: 24-Jan-2018

[27] Gezici S, Tian Z, Giannakis G B, Kobayashi H, Molisch A F, Poor H V, Sahinoglu Z. Localization via ultra-wideband radios: a look at positioning aspects for future sensor networks. IEEE Signal Processing Magazine, 2005, 22(4): 70–84

[28] Sadi F, Johnson T, Klukas R. Simulation of a non-coherent UWB transceiver design–noise and impairment analysis. International Journal of Ultra Wideband Communications and Systems, 2012, 2(4): 216–224

[29] Bharadwaj R, Swaisaenyakorn S, Parini C G, Batchelor J C, Alomainy A. Impulse radio ultra-wideband communications for localization and tracking of human body and limbs movement for healthcare applications. IEEE Transactions on Antennas and Propagation, 2017, 65(12): 7298–7309

[30] Zhang W, Chowdhury M I S, Kavehrad M. Asynchronous indoor positioning system based on visible light communications. Optical Engineering, 2014, 53(4): 045105

[31] Wu D, Ghassemlooy Z, Zhong W D, Khalighi M A, Minh H L, Chen C, Zvanovec S, Boucouvalas A C. Effect of optimal Lambertian order for cellular indoor optical wireless communication and positioning systems. Optical Engineering (Redondo Beach, Calif.), 2016, 55(6): 066114

[32] Li L, Hu P, Peng C, Shen G, Zhao F. Epsilon: a visible light based positioning system. In: Proceedings of 11th USENIX Conference on Networked Systems Design and Implementation. Seattle,WA, USA: ACM, 2014, 331–343

[33] Arafa A, Dalmiya S, Klukas R, Holzman J F. Angle-of-arrival reception for optical wireless location technology. Optics Express, 2015, 23(6): 7755–7766

[34] Armstrong J, Sekercioglu Y A, Neild A. Visible light positioning: a roadmap for international standardization. IEEE Communications Magazine, 2013, 51(12): 68–73

[35] Jin X, Holzman J F. Differential retro-detection for remote sensing applications. IEEE Sensors Journal, 2010, 10(12): 1875–1883

[36] Collier C M, Jin X, Holzman J F, Cheng J. Omni-directional characteristics of composite retroreflectors. Journal of Optics A, Pure and Applied Optics, 2009, 11(8): 085404

[37] BergenMH, Arafa A, Jin X, Klukas R, Holzman J F. Characteristics of angular precision and dilution of precision for optical wireless positioning. Journal of Lightwave Technology, 2015, 33(20): 4253–4260

[38] Davis J, Hsieh Y H, Lee H C. Humans perceive flicker artifacts at 500 Hz. Scientific Reports, 2015, 5(1): 7861

[39] Dempster A G. Dilution of precision in angle-of-arrival positioning systems. Electronics Letters, 2006, 42(5): 291–292