Research On The Ranging And Localization Used By UWB In LOS/NLOS Environment

With the continuous development of social science and technology,the wide application of computer and mobile communication technology,people have higher and higher requirements for the acquisition of location information and accuracy.GPS technology of GPS has been used outdoors with high precision and low terminal price.It is widely used worldwide.However,the characteristics of many obstacles and complex signal propagation paths in the indoor environment make GPS not suitable for indoor positioning technology.UWB technology is very suitable as an indoor high-precision ranging and positioning technology because of its low transmission power,strong multipath resolution capability and strong penetrating power.Therefore.the research of indoor ranging and positioning technology based on ultra-wideband has great theoretical and practical significance.Firstly,this paper focuses on the indoor positioning requirements based on UWB technology,and determines the overall design of the distance measuring system.The hardware platform of distance measuring module is constructed by means of main control module and radio frequency module.and the hardware circuit diagram of power supply module,radio frequency circuit module and main control circuit is given.Also focuses on indoor locating method based on UWB technology,introduces the IEEE802.15.4 a criteria of UWB channel model and algorithms ranging,and through the analysis of the advantages and disadvantages of them,error,select the SDS-TWR ranging algorithm based on TOA.based on the idea of time series analysis state machine for the main control chip and software design of the rf chip,the program flow chart is given.On this basis,in view of the UWB technology in LOS/indoor NLOS propagation properties are studied in the conditions of main factors that affect the precision of ranging made detailed analysis and put forward the corresponding optimization measures,making use of the existing technology in LOS indoor environment can achieve high accuracy.then introduces two methods of discriminant LOS/NLOS.and designed the experimental discriminant LOS/NLOS preliminary criterion is given.Finally,the physical platform is built to test it.The experimental results show that the distance error between the coordinates of the moving tag node and its actual coordinates can be controlled within 15cm,which proves that the positioning system constructed in this paper has a higher positioning accuracy.