Design And Implementation Of Indoor Positioning System Based On UWB

With the development of wireless sensor networks and mobile communications,the location service has seen a fast rise.At present,satellite positioning has been able to meet our requirements outdoors.However,the complex indoor environment and severe block make the technique impossible indoors.To deal with the problem of indoor high precision location,we design a UWB-based indoor positioning system.Our contributions are as follows:Firstly,we report an overview of some existing indoor location technologies.By comparing system cost,practicability,accuracy and other factors,we select UWB positioning as the research topic.For a further understanding of it,we introduce its definition and implementation.Secondly,common location models and algorithms are presented,then the TOA principle is adopted by comparision of complexity and reliability,which has two steps,ranging and position calculation.Those steps jointly affect precision.For ranging,TOA-based algorithms are studied,after that we discuss the influence of clock offset on the ranging,then give the error simulation diagrams,lastly select the asymmetric double-sided two-way ranging scheme.In actual location,to solve the problem of no solution of equations,the least squares algorithm is proposed in this thesis,which can estimate the optimal position of the tag.Thirdly,based on STM32 chip and the DWM1000 module,we complete the design and implementation of hardware and software.In terms of hardware,we finish the schematic drawing and the design of PCB layout.For software,it mainly has two functions,positioning and location display.Finally,two measurements are arranged,an end-to-end ranging test and a three-station-based positioning estimation.Then we analyze the causes of ranging errors and correct them.After correction,ranging accuracy and location precision are 10 cm and 20 cm,respectively.It can be seen that the system has met the requirements of indoor high-precision positioning.