Enhanced Location Estimation with the Virtual Base Stations in Wireless Location Systems

Mobile location estimation has attracted a significant amount of attention in recent years. The network-based location estimation schemes have been widely adopted based on the radio signals between the mobile device and the base stations. The two-step Least Square (LS) method has been studied in related research to provide efficient location estimation of the mobile devices. However, the algorithm may results in inaccurate location estimation under (i) the existence of the Non-Line-Of-Sight (NLOS) errors and (ii) poor Geometric Dilution of Precision (GDOP) circumstances. A location estimation algorithm with the Virtual Base Stations (VBS) is proposed in this paper by considering the geometric layouts between the mobile device and its associated base stations. In order to enhance the precision of the location estimate, the VBS scheme is designed to incorporate the virtual base stations and the related geometric constraints within the formulation of the two-step LS method. The proposed VBS scheme can both preserve the computational efficiency from the two-step LS algorithm and obtain precise location estimation under poor GDOP and NLOS environments. Numerical results demonstrate that the proposed VBS algorithm can achieve better accuracy, comparing with other existing schemes, in mobile location estimation.