Research On The Key Technology Of Ultra-wideband Positioning

With the development of wireless communication technology and the popularity of the Internet of Things,location-based services(LBS)are more and more widely used in real life,and people's requirements for LBS are getting higher and higher.The global positioning system(GPS)can provide people with accurate location information in an open outdoor environment,but the positioning accuracy is not ideal in an environment with many obstructions and dense buildings,which cannot satisfy people's close-range complex environment.The positioning needs,therefore,how to achieve high-precision positioning in a close-range complex environment has become the focus of research.With the introduction and development of ultra-wideband communication technology,Ultra Wideband(UWB)technology is widely used because of its strong anti-multipath capability,penetrating power and high positioning accuracy compared with other wireless communication technologies.For high precision close proximity wireless positioning system.In this thesis,the traditional TDOA(Time Difference of Arrival)method has the limitations of accurate synchronization of anchor node clock and low applicability.An innovative passive S-TDOA(Sequential-TDOA)method is proposed,and the system hardware designed in this thesis is proposed.Implemented on.The main work of this thesis includes:The basic principles of common wireless positioning methods are analyzed.The related UWB positioning algorithms are studied.The sources of positioning errors and the evaluation criteria of positioning accuracy are analyzed.Through the analysis of common TDOA methods,the common TDOA method has the limitations of accurate synchronization of anchor node clock and low applicability.A passive S-TDOA method for eliminating the influence of anchor node clock frequency deviation is proposed.The effect and measurement accuracy are theoretically verified.3.Design and implement the system hardware module for the overall scheme of the ultra-wideband positioning system.The TOA(Time of Arrival)method and the ultrawideband positioning system based on the passive S-TDOA method are designed and implemented on the hardware of the system.In the design and implementation of the ultra-wideband positioning system based on TOA method,a symmetric bilateral bidirectional ranging method suitable for the system hardware of this thesis and with small error is selected.The concept of time-sharing TOA system communication timing is proposed and implemented on the system hardware designed in this thesis.The Newton iterative localization algorithm based on TOA method is selected and implemented.Correlation tests were carried out in indoor and outdoor environments,and the measurement results showed that the positioning system achieved a positioning accuracy of 40 cm.In the design and implementation of the ultra-wideband positioning system based on the passive S-TDOA method,the passive S-TDOA method is implemented on the system hardware and the performance analysis is carried out.The concept of chained S-TDOA system communication timing is proposed and implemented on the system hardware of this thesis.The extended Kalman filter localization algorithm based on TDOA method is selected and implemented.Correlation tests were carried out in indoor and outdoor environments.The measurement results verified the feasibility of the passive S-TDOA method in the field of ultra-wideband positioning.The positioning accuracy reached 30 cm,the location update rate reached 220 times/s,and there was no limit on the number of users.