Rsearch On Indoor Positioning Technology Based On UWB/IMU

Indoor positioning services have attracted more and more attention and have broad application prospects,but a single indoor positioning technology cannot meet the positioning needs of most indoor scenarios.This thesis studies the positioning technology based on Ultra Wide Band(UWB)and the positioning technology based on Inertial Measurement Unit(IMU).The advantages and disadvantages of the two are analyzed,and the two are combined to achieve complementary advantages and improve the positioning accuracy of the system in the non-line-of-sight environment.Aiming at the positioning problem of UWB in complex indoor environments,this thesis proposes an improved geometric positioning method based on weighted shrinking and growing circles technique(WSGC)to solve the problem.The WSGC algorithm obtains a smaller intersection area by shrinking and expanding the circle,and calculates the mean value of the intersection area to obtain the positioning result.In this thesis,the localization performance of the WSGC algorithm,the least squares algorithm and the algorithm of literature [60] in line-of-sight and non-line-of-sight environments is verified through simulation experiments,and experimental tests are carried out for static and dynamic,line-ofsight and non-line-of-sight environments in real environments,verifying the improved WSGC algorithm has higher positioning accuracy.For the positioning problem of the IMU,a cadence detection method for window processing of synthetic acceleration is designed in this thesis to improve the accuracy of the cadence detection results.After that,a step size estimation scheme based on the residual speed to correct the stride speed is proposed to improve the step size estimation accuracy.Through the above analysis,the IMU positioning scheme based on the synthetic acceleration and the residual velocity to correct the step size of the stride speed estimation is finally adopted in this thesis,and then the IMU positioning experiment is carried out to verify that this scheme can improve the IMU positioning accuracy.In view of the two problems of the large UWB positioning error in the non-line-of-sight environment and the large positioning error of the IMU due to the accumulated error,a combined UWB/IMU indoor positioning scheme based on Extended Kalman Filter(EKF)is proposed in this thesis.Comparing with the algorithm that only uses UWB positioning or IMU positioning and the UWB/IMU combined positioning algorithm based on Kalman Filter(KF),the results show that the combined UWB/IMU indoor positioning scheme based on Extended Kalman Filter can improve the positioning accuracy and suppress the path deviation,and have better performance.