Optimization Of UWB Indoor Positioning System Based On TWR Ranging Technology

With the development of science and technology and the improvement of people’s life quality,more and more attention is paid to the high-precision location information service.At present,outdoor space satellite positioning system has been able to meet most of people’s location needs.However,in indoor environment,due to the influence of obstacles such as walls and buildings,it is difficult for the satellite positioning system to achieve accurate positioning.ultra wide band(UWB)is widely used for high-precision positioning in indoor environments due to its strong penetration,low power consumption,strong anti-noise capability and ultra-high time resolution.Based on UWB positioning technology,this paper proposes a corresponding optimization scheme for the problem of NLOS ranging and indoor multipath effect in the complex indoor pedestrian tracking environment.The main work of this paper is as follows:Firstly,aiming at the influence of wall reflection and human shielding on UWB ranging signal in indoor environment,a statistical model of ranging error based on experimental measurement data was proposed.Based on this model,the critical point is determined as the leading factor of measurement error.Within the critical point,the human body shielding effect is the main factor of measurement error,whereas the reflection of the wall outside the critical point is the main factor of measurement error.Subsequently,the paper focuses on the analysis of the influence of human body occlusion on the measurement accuracy under different angles within the critical point.Based on a large number of ranging experiments,the human body occlusion error model was fitted by MATLAB,and the generalized extreme value distribution was determined to be more consistent with the error distribution caused by human body occlusion.The proposed error model is integrated into the particle filter algorithm,and the simulation results show that the proposed error model can effectively weaken the influence of human body occlusion on the measurement accuracy,and the ranging accuracy is obviously improved.Finally,in view of the large diameter reflection error outside the critical point cannot be filtered,this paper analyzes the theoretical value of the error by geometric reflection principle,and verifies the rationality of the analysis through experiments.After determining the error size,the error compensation scheme is used to correct the distance measurement.On the basis of accurate ranging,comparative analysis verifies that the centroid positioning algorithm with error compensation has higher positioning accuracy than the least squares estimation method.To sum up,aiming at the problems of human body occlusion and multipath reflection effect in indoor positioning,this paper adopts the method of ranging error modeling and reflection error compensation to improve the ranging accuracy,and verifies that the centroid positioning algorithm has higher positioning accuracy on this basis.