Abstract:

In indoor wireless localization environment, signal propagation is complicated due to the nonline of sight (NLOS). Traditional algorithms such as LS and Chan cannot achieve satisfactory accuracy. In this Paper, using the passive UHF RFID technology, we analyze and build a channel model, and then discuss localization errors. Based on the distance information obtained from the phase of arrival (POA), we propose a twostep tag localization algorithm. First, we use the interior point (IP) algorithm to solve the NLOS problem. Through multiple iterations, the NLOS bias can be removed from phasebased range measurement. Based on the revised range results, we utilize the residual weighted algorithm to get the accurate RFID tag position. Comparison of the simulation results demonstrates that the proposed method outperforms the traditional methods.

Key words: UHF RFID;nonline of sight (NLOS);indoor localization;phase of arrival (POA);interior point algorithm;residual weighted algorithm (Rwgh)