TOA and FOA Based Acoustic Indoor Localization in NLOS Environment

NLOS (Non-Line-of-Sight) phenomenon has posed a great challenge for practical applications of acoustic smart devices in complex indoor environments. Identifying-discarding NLOS measurements strategy will introduce a critical condition for many positioning methods in the real applications, because at least 3 measurements are needed for calculation process. In order to realize robust indoor localization for COTS smart devices in dense NLOS environments and low deployment density of beacons, a novel localization method based on TOA (Time of Arrival) and FOA (Frequency of Arrival) of acoustic signal is proposed by using particle filtering. Based on the Doppler-invariant property of HFM signals, TOA and FOA estimation method is introduced to realize speed and range estimation simultaneously. The results obtained from numerical simulations show that the positioning performance of our proposed method is higher than the classical ML estimator. The experimental investigation verified that only 2 LOS acoustic signals are needed for 2D positioning, which means a higher scenario adaptive capability and promotional value.