Robust Weighted Least Squares Method for TOA-Based Localization Under Mixed LOS/NLOS Conditions

In this letter, the time-of-arrival-based localization problem under mixed line-of-sight/non-line-of-sight conditions is addressed. Based on the a priori information of known path status, we propose a new robust weighted least squares (RWLS) method to improve the performance of the existing RWLS method, and the weights in the new RWLS problem are derived and explicitly given. The proposed RWLS problem is approximately solved by employing the second-order cone relaxation technique. Furthermore, when the path status is incorrectly identified, we propose a procedure of correcting the incorrect path status to make the RWLS method robust against the path status identification errors. The performance of the new RWLS method is verified by computer simulations.