Research on NLOS Mitigation Method for TOA Positioning

Abstract

In Time of Arrival (TOA) positioning technology based on base station (BS), besides the measurement error caused by mobile station (MS), Non Line Of Sight (NLOS) propagation become the main factor of the positioning error. Aiming to solve this problem especially in indoor positioning, we introduced the differential calculus method to linearize the positioning equations, and Mirror Image Method (MMI) to turn the NLOS propagation into LOS propagation, then we collected a small amount of feature point information in the positioning region which include the received TOAs at this point, feature point coordinates and BS coordinates or the mirror image coordinates of BS. In the following 3D scenario simulation, we took use of the differential calculus as well as Least Square (LS) method to get the position of the MS. Simulation results show that by using the whole mechanism, we can achieve a high positioning precision.