Research On Ultra-wideband Accurate Localization Algorithms In Complex Indoor Environment

In the era of rapid development of the Internet of Things(IOT)and Cyber Physical Systems(CPS),quickly obtaining the location information of indoor people,equipment and other objects is now one of the most concerned and fastest growing fields.Ultra-wideband(UWB)indoor positioning has become a popular technology for indoor localization due to its advantages of low-cost,low-power consumption,anti-multipath interference and strong penetration ability.However,with the increasing demand for indoor location services,UWB indoor localization system still faces some challenges.Therefore,this paper conducts an in-depth study on the accurate positioning of UWB system in complex indoor environments.The main research contents are briefly described as follows.(1)To alleviate the positioning error caused by non-line-of-sight(NLOS),an optimization system based on UWB and inertial navigation unit(IMU)is propose d.The interacting multiple model(IMM)filter is optimized by adding a velocity observation and a power adaptive Markov probability transfer matrix is proposed which makes the IMM filter algorithm more adaptable to the complex environmen t and better smooth the ranging affected by NLOS.Experimental results show tha t the proposed UWB and IMU infusing system has superior positioning performan ce,compared with extended Kalman filter(EKF)-based pedestrian dead reckoning(PDR)/UWB(PDR/UWB-EKF),EKF-outlier-based PDR/UWB(PFR/UWB-EKFO)and EKF-based IMM-UWB(IMM-EKF).(2)To avoid the error caused by NLOS,a UWB channel impulse responses(CIR)based geometric positioning system is proposed.The mapping relationship between CIR and indoor position is obtained by theoretically analyzing the CIR model.17 features from the UWB CIR is used in machine learning to locate the region,then the line-of-sight(LOS)links are selected for geometric positioning.Finally,Experimental results show that the UWB CIR based geometric positioning system can achieve more accurate and robust performance in the complex indoor environment compared with trilateral positioning(TP)and power outlier trilateral positioning(PO-TP).The proposed UWB positioning system provides a very important alternative technology for mitigating and avoiding the impact of NLOS errors.