Non-cooperative accurate localization of a mobile station (MS) operating over the GSM bandwidth is particularly challenging in Non Line of Sight (NLOS) scenarios. Under this condition, classical localization techniques which rely on the knowledge of the signal strength, the relative delay, and/or the angle of arrival (AoA) at the BSs of the multipath components of the channel impulse response, fail to reach sufficient accuracy for practical applications. The environment where both the BS and the MS were located was assumed to be perfectly known and under NLOS conditions. This environment was numerically modelled and subsequently injected into a ray-launching tool to simulate the BS/M S uplink characteristics. In a previous work, we proposed experimental localization results of a MS via the minimization of a hybrid metric combining spectral correlation and multipath component distance (MCD). On the one hand, spectral correlations were computed between measured channels and channels synthesized with the ray-launching technique at 1.3 GHz over a 22 MHz bandwidth. On the other hand, the MCD matrices were fed with the AOA and relative time of arrival (TOA) of the strongest experimental/ray-launching rays; a high-resolution parameter estimator being used to extract this information from the measured channels. Localization errors between 0 and 6 m were obtained when 2 BSs were deployed depending upon the investigated scenario. In the current work, we describe how to incorporate the polarization diversity into the hybrid metric as an additional flexibility to improve the localization accuracy; the orientation of the MS antenna being a-priori unknown. Experimental r esults show a 50% improvement of the localization error when 2 BSs are used.
