High Precision Indoor Positioning System Based on UWB/MINS Integration in NLOS Condition

Targeting a seamless and precise indoor localization in NLOS condition, a high-precision positioning system based on UWB/MINS integration is designed in this work. The proposed system is a low-cost and small-size multi-sensor platform in which an MIMU is added to a classical UWB indoor positioning system that implements the TOA algorithm. Particularly, when the lack of sufficient anchor nodes occurs, compared with the single UWB system, the enhanced performance of this system mainly benefits from the effective NLOS identification for every node and the tightly-coupled fusion strategy based on extended Kalman filter. The former prevents this system from the interference caused by erroneous indirect-path signal, which utilizes the power strength of UWB received signal to distinguish LOS and NLOS condition. The latter takes full advantage of the kinematic constraints to maintain positioning accuracy. Remarkably, when there are only two valid TOA signals, experimental results validate that the performance of the proposed system which provides centimeter-level positioning accuracy outperforms that of traditional UWB positioning system which fails in NLOS condition.