Research on UWB Localization Based on TOA in Indoor NLOS Environment

To solve the problem of Ultra-wideband (UWB) TW-TOA ranging accuracy influenced by multipath and non-line-of-sight(NLOS) errors in indoor environment, the performance of UWB signal in indoor NLOS propagation environment is firstly analyzed, and then based on the basic Kalman filter, a two-state Kalman filter algorithm is proposed, which ajusts the Kalman filter gain according to the size of the residual error. If the filter residual is greater than the threshold, the UWB signal is judged as a NLOS signal and the filter gain is set to zero, and replace the current state estimate with a state prediction, otherwise, the basic Kalman filter algorithm is used. Finally, the UWB performance of CM4 in the IEEE802.15.4a channel model is analyzed through simulation, simulation on static nodes and dynamic users in indoors is performed, which verifies the validity and reliability of the dual-state Kalman filter algorithm and can be applied in medical field for patients tracking in real time and so on.