NLOS error mitigation and mobile tracking

A novel hybrid wireless positioning method in non-line of sight (NLOS) situation is proposed in this paper. Firstly, a Kalman filter (KF) is used to track the NLOS bias in the time of arrival (TOA) measurements so as to mitigate the NLOS error. Secondly, another KF combines the most three common positioning methods, the time difference of arrival (TDOA) positioning, the TOA positioning and the angle of arrival (AOA) positioning, to achieve high location accuracy. Bused on linear forms of the measurement equations, the location estimator that use the linear KF (LKF) rather than the extended KF (EKF) is developed, thus the computation can be simplified. Simulation shows that the proposed hybrid method gives good performance.