Research And Implementation Of Indoor Positioning Method Based On UWB And IMU

In recent years,the demand for real-time and accuracy of navigation and positioning services has become stronger.Outdoors,satellite navigation technology meets the needs of most positioning scenarios,but the indoor environment is complex and changeable,and the satellite signal attenuation is severely unable to complete positioning.Ultra Wide Band(UWB),as one of the preferred solutions for indoor high-precision positioning,has a positioning accuracy of centimeter level in a line-of-sight environment.However,due to the influence of non-line-ofsight errors,the positioning accuracy is seriously reduced.The inertial navigation system based on Inertial Measurement Unit(IMU)has a high positioning accuracy in a short time,but the positioning error accumulates over time and the positioning accuracy is low in a long time.In response to the above problems,the UWB/IMU combined positioning algorithm is studied,and the advantages of the two are used to complement each other to achieve high-precision positioning in a complex environment.Under this premise,the designed combined positioning system is applied to the smart car to improve the running accuracy and flexibility of the car,and realize the intelligent tracking of the car.The main research content includes the following points:1.A channel equalization technology based on the Least Mean Square(LMS)algorithm is proposed to reduce the interference of multipath and noise on the signal,improve the performance of the relevant receiver,and obtain high-precision UWB ranging values.Experimental results show that the UWB ranging accuracy can reach the centimeter level after using this technology,which meets the needs of high-precision positioning.2.The IMU error modeling and correction are realized.Aiming at the problem of attitude divergence caused by the accumulated error of gyroscope,the complementary filter combined with PI control is used to solve the attitude,which can effectively suppress the accumulated error of gyroscope and improve the attitude detection accuracy of gyroscope.3.The Extended Kalman Filter(EKF)is used to construct the UWB/IMU combined positioning algorithm.In the line-of-sight environment,the cumulative error of the IMU is corrected according to the ranging information of UWB high-precision.In the non-line-of-sight environment,the position information calculated by the inertial navigation system in a short time is used to assist the UWB to complete the positioning.On the basis of the oretical research,a combined positioning system was developed,and a system experimental platform was built in an indoor environment to complete the collection and storage of experimental data.Experimental results show that the combined positioning system can effectively suppress nonline-of-sight errors,and compared with a single UWB positioning,the positioning accuracy and stability are greatly improved.4.The intelligent tracking car based on STM32 is designed,which applies a combined positioning system to solve the current problem that the tracking of intelligent car mostly relies on pre-paved trackers.Due to better running accuracy and flexibility,the car has the ability to track intelligently.The content studied in this thesis provides ideas for solving the problem of low UWB positioning accuracy in complex environments.Simulation experiments show that the UWB/IMU combined positioning system can achieve high-precision navigation and positioning and meet the needs of high-precision positioning.