TDOA/AOA localization in RFID system using dual indirect Kalman filter

The time difference of arrival (TDOA) is one of the most accurate localization techniques used in real time locating system (RTLS). However, environmental error and non-line-of-sight (NLOS) error undermine the accuracy of tracking. In order to reduce NLOS error influence, NLOS identification needs to be performed using TDOA standard deviation. After the NLOS identification, we use the additional angle of arrival (AOA) measurements from identified LOS base station. We propose dual indirect Kalman filter (DIKF) which includes error state filter and weight filter to estimate the position of target. The effectiveness of DIKF has been proved by comparing the tracking performance with reference through simulation results.