Research On Indoor Localization Method Based On UWB And Inertial Measurement Device

Accurate and real-time indoor positioning technology has a wide range of application requirements,and with the progress of related technology has become a research hotspot.At present,wearable indoor positioning has received wide attention in the areas of child and elderly care,human movement morphology analysis,rehabilitation medicine,robot navigation,and so on.Among many wearable indoor positioning technologies,Ultra-Wide Band(UWB)positioning technology and Inertial Measurement Unit(IMU)positioning technology are the main methods widely used at present.However,UWB positioning is vulnerable to signal stability and occlusion between nodes and base stations.IMU positioning cannot avoid signal drift caused by error accumulation,which limits the further improvement of positioning accuracy of both.In this dissertation,the integration method of UWB technology and IMU technology is studied in depth,and the iteration compensation of the two measurement results is explored to make full use of the long-term stability of UWB positioning results and the advantages of high accuracy and single-step accuracy of the IMU System,as well as the calculation of speed direction and other key parameters.A lightweight,wearable,battery-powered,low-cost indoor positioning system solution was designed,and the corresponding measurement data fusion method was proposed.At the same time,the positioning accuracy can be improved,and the posture data of the human body part installed by the sensor can be obtained to meet the requirements of further data analysis in the application of the Internet of Things.The main research contents of this dissertation include:(1)Design a wearable wireless sensor hardware system with low power consumption and small size,which is constructed by low cost components,taking STM32 single-chip computer as the main control module,and integrates the ultra-wideband module DWM1000,the inertial measurement unit MPU9250 and the Bluetooth module JDY-32,respectively.(2)In order to reduce the influence of clock bias and improve the ranging accuracy,a two-sided bidirectional ranging method is applied to reduce the error caused by clock bias between base station and label in UWB system.The idea of centroid positioning is introduced into the three-sided positioning,which makes up for the defect of low accuracy of single three-sided positioning method.(3)In the inertial measurement system,the complementary filter is used to calculate the rotation attitude of the sensor,and the quaternion is used to convert the carrier coordinate system to the navigation coordinate system,and the continuous position estimation is obtained by the integral method.For the complementary characteristics of positioning results between UWB and IMU,an improved Kalman filter algorithm is applied to achieve the fusion of positioning data.The designed sensor system and the calculation method are verified experimentally.The experimental results show that the integrated positioning system based on UWB/IMU reduces the UWB single-step error by motion posture estimation and compensates the accumulation of inertial measurement error by the long-time stability measured by UWB.Compared with single positioning technology,the design method improves positioning accuracy and stability significantly.