Enhanced position location with UWB in obstructed LOS and NLOS multipath environments

We propose an enhanced directional beacon based position location procedure for UWB systems. Unlike previous work that relies on strongest return and therefore prone to errors in obstructed line of sight (OLOS) and non-LOS (NLOS) environments, our procedure identifies the LOS return by detecting the earliest arrival. To overcome synchronization problems, we propose a correlation based window algorithm to detect the earliest arrival and hence the LOS component across a 360° rotation of directional beacon. We extend the algorithm to non-LOS (NLOS) case and estimate position by minimizing the norm between the sets of measurements. To assess the performance over realistic UWB channels, we modify the UWB channel model to incorporate the effect of directional transmitting antennas. From simulation results we claim position location accuracy of around 34 cm with a pragmatic 4-element antenna array using 2.4GHz UWB pulses and 4-bit A/D converter at 24dB SNR.

[1]  Kai Li,et al.  A directionality based location discovery scheme for wireless sensor networks , 2002, WSNA '02.

[2]  Woo Cheol Chung,et al.  Performance evaluation of an ultra wideband radiolocation system with directional beacon , 2004, Proceedings. 2004 IEEE Radio and Wireless Conference (IEEE Cat. No.04TH8746).

[3]  L. Godara.  Application of antenna arrays to mobile communications. II. Beam-forming and direction-of-arrival considerations , 1997, Proc. IEEE.

[4]  Woo Cheol Chung,et al.  An accurate ultra wideband (UWB) ranging for precision asset location , 2003, IEEE Conference on Ultra Wideband Systems and Technologies, 2003.

[5]  Robert A. Scholtz,et al.  Ranging in a dense multipath environment using an UWB radio link , 2002, IEEE J. Sel. Areas Commun..

[6]  Michael A. Jensen,et al.  A statistical model for angle of arrival in indoor multipath propagation , 1997, 1997 IEEE 47th Vehicular Technology Conference. Technology in Motion.

[7]  J. Foerster,et al.  Channel modeling sub-committee report final , 2002 .

[8]  Juha-Pekka Makela,et al.  Indoor geolocation science and technology , 2002, IEEE Commun. Mag..

[9]  Kegen Yu,et al.  UWB positioning for wireless embedded networks , 2004, Proceedings. 2004 IEEE Radio and Wireless Conference (IEEE Cat. No.04TH8746).