Design And Implementation Of Indoor Positioning System Based On UWB

With the development of wireless communication technology and the popularization and application of the Internet of things in various industries,intelligent terminals and smart devices are gradually popularized.Location-based services(LBS)have become the essential functions such as positioning and navigation,emergency search and rescue,rescue and relief,and commodity shopping guide.As the core of LBS,the demand for high-precision indoor positioning is increasingly prominent.Because ultra-wideband(UWB)signal has extremely high time resolution,high ranging accuracy,strong penetration,good resistance to multipath effect,it is very suitable for the design of high-precision indoor positioning system.In the design of indoor positioning system based on UWB,the non-line-of-sight propagation effect and the position solving algorithm have important effects on improving the positioning accuracy.This paper analyzes and studies the non-line-of-sight recognition technology and fusion positioning technology in indoor environment,and designs and develops an indoor positioning system based on UWB.The main research contents are as follows:(1)For the indoor propagation of UWB signals with LOS and NLOS,the convolution neural network(CNN)is used to identify NLOS signals.To avoid overfitting caused by limited data sets,dropout is adopted to reduce the dependence between neurons and improve the recognition rate of NLOS signals.After NLOS identification,the LS/WLS algorithm was used for positioning.(2)Combined with the characteristics of UWB signal bandwidth and high time resolution,TWR was selected as the ranging scheme of the positioning system.First,Kalman filtering algorithm was used to smooth the ranging values based on TDOA parameters,and then Chan algorithm was used to perform the location solution.(3)To design and develop a set of indoor positioning system based on UWB,choose Decawave company DW1000 UWB RF transceiver chip as the core unit,ST company produces the STM32 as main control unit,completed the main control unit circuit,UWB transceiver unit circuit,unit serial communication circuit and power circuit design and software design of distance measuring and positioning algorithm.Elaborated the system hardware design and the system software work flow,carries on the choice and the construction to the whole research and the realization hardware and software structure;The real-time positioning,electronic fence and other core functions are completed,and the ranging and positioning accuracy are improved through error calibration.Finally,the UWB positioning system designed in this paper is tested and verified to be effective in the actual environment.