Three-dimensional indoor localization in Non Line of Sight UWB channels

The problem of indoor localization is lately gaining high interest in research and industry. In this context, Ultra-Wideband has the capability of fulfilling the task of precise localization. Non Line of Sight (NLOS) channels, however, can seriously degrade the positioning accuracy. This paper gives a contribution to the frequent case, where base station redundancy in a three-dimensional localization system in time-of-arrival (TOA) configuration is not available. Literature analysis shows that many existing NLOS mitigation algorithms cannot be applied in such a case. Therefore, an algorithm using geometrical projection is proposed in comparison to Kalman filtered range estimates. Both algorithms rely on NLOS detection, which is implemented using the change of SNR method. Finally, the algorithms are tested in a laboratory room using an UWB localization test bed.