Hybrid Range Based Indoor Wireless Localization using Unconstrained Nonlinear Optimization for UWB Applications

Abstract In this paper, a hybrid TOA/RSSI wireless localization is proposed for accurate positioning in indoor UWB systems. The major problem in indoor localization is the effect of non-line of sight (NLOS) propagation. To mitigate the NLOS effects, an unconstrained nonlinear optimization approach is utilized to process Time-of –arrival (TOA) and Received Signal Strength (RSS) in the location system.TOA range measurements and path loss model are used to discriminate LOS and NLOS conditions. The weighting factors assigned by hypothesis testing, is used for solving the objective function in the proposed approach. This approach is used for describing the credibility of the TOA range measurement. Performance of the proposed technique is done based on MATLAB simulation. The result shows that the proposed technique performs well and achieves improved positioning under severe NLOS conditions.

[1]  Saeed S. Ghassemzadeh,et al.  The Ultra-wideband Indoor Path Loss Model , 2002 .

[2]  Saipradeep Venkatraman,et al.  A novel ToA location algorithm using LoS range estimation for NLoS environments , 2004, IEEE Transactions on Vehicular Technology.

[3]  J. Holtzman,et al.  The non-line of sight problem in mobile location estimation , 1996, Proceedings of ICUPC - 5th International Conference on Universal Personal Communications.

[4]  Gordon L. Stüber,et al.  Overview of radiolocation in CDMA cellular systems , 1998, IEEE Commun. Mag..

[5]  J. J. Caffery,et al.  A new approach to the geometry of TOA location , 2000, Vehicular Technology Conference Fall 2000. IEEE VTS Fall VTC2000. 52nd Vehicular Technology Conference (Cat. No.00CH37152).

[6]  R. E. Munson.  Antennas for wireless communications , 1995, 1995 IEEE Aerospace Applications Conference. Proceedings.

[7]  G.B. Giannakis,et al.  Localization via ultra-wideband radios: a look at positioning aspects for future sensor networks , 2005, IEEE Signal Processing Magazine.