Joint position and clock tracking of wireless nodes under mixed LOS-NLOS conditions

We propose an algorithm for the simultaneous position and clock tracking of a wireless mobile node by a set of reference nodes. Based on a protocol similar to that of two-way ranging, our algorithm efficiently estimates the position and velocity of the mobile, and the skew and offset of its clock. We take into account that the propagation conditions between each reference node and the mobile change as the latter moves. In particular, changes between line-of-sight (LOS) and several non-line-of-sight (NLOS) scenarios are considered. We study the performance of our algorithm and compare it to other relevant proposals in the literature by means of simulations, showing that our proposed method improves localization accuracy.