Joint Particle Filter and UKF Position Tracking Under Strong NLOS Situation

The location performance within a wireless communication system is severely impaired by biases introduced in the range measures because of the Non-Line-Of-Sight (NLOS) condition, caused by obstacles in the transmitted signal path. Usually not all the base stations (BS) are in NLOS, and the knowledge of the LOS-NLOS situation for each measure can improve the final positioning accuracy [6]. This paper studies the use of a Particle Filter (PF) to track the LOS-NLOS situation for each BS. A Rao-Blackwellized approach is used to estimate both the position, by an appropriate Unscented Kalman Filter (UKF), and the situation, by a PF. The approach shows a remarkable reduction in positioning error and a high degree of scalability in terms of performance versus complexity.