Research And Implementation Of High-precision Ranging And Positioning Algorithm Based On FMCW Radar

Frequency Modulated Continous Wave(FMCW)radar realizes ranging by measuring the frequency difference between the echo signal and the transmitted signal.So instead of measuring time delay,we just need to measure the frequency difference,making high-precision ranging easier to achieve.On the one hand,based on the analysis of the current research situation,it is urgent to develop a FMCW radar system which integrates ranging and identification functions.On the other hand,with the development of Inthernet of Things(Io T),the accuracy of object location becomes increasingly important.FMCW radar positioning system has the advantages of high positioning accuracy,low deployment difficulty and low cost.Therefore,it is of great significance to design a high-precision ranging and positioning FMCW radar system with identification function.This thesis focuses on high-precision ranging algorithm for single target,multitarget identification and high-precision ranging,high-precision location algorithm for single target and measurement and analysis of high-precision ranging algorithm for single target based on FMCW radar hardware platform.As for multi-target identification and high-precision ranging of single target or multi-target,the main work and innovations are as follows:For multi-target ranging,we design a FMCW radar system which integrates ranging and identity information recognition,and propose two ways to realize multi-target recognition: correlation identification and FFT Ranging(CI-FR)and correlation identification and ranging(CIR).Firstly,The Cubic Spline Interpolation(CSI)algorithm is applied to beat signal spectrum processing.CSI improves the ranging accuracy efficiently.Then to improve ranging accuracy,this thesis uses Dither Method(DM)and Improving Dither Method(IDM).Both methods can improve the ranging accuracy of FMCW radar.When the number of dithering is 1000,the two methods can theoretically improve the ranging accuracy of single or multiple targets to mm level.Next,a method of improving ranging accuracy by using DFT phase information is proposed.For single target ranging,the phase information corrects the frequency difference,so that the accuracy of frequency difference can theoretically reach mm level.For multitarget ranging,two methods are proposed to obtain the phase of the principal component signal.The hardware platform of FMCW radar is built,and the accuracy of high precision ranging algorithms is tested on the platform.The measurement results of single target high precision ranging algorithm are: DM,IDM and phase information algorithm can improve the ranging accuracy to mm level,and the ranging accuracy of using phase information is better than that of IDM,and IDM is better than DM.For multi-target high-precision ranging algorithm,the conclusion is similar to that of single-target ranging.For FMCW radar single target high-precision positioning algorithm,the main work and innovations are as follows:Under the condition of accurate ranging and inaccuracy ranging,the positioning principles of single target in three-dimensional space are introduced.In the case of inaccuracy ranging,we need to estimate the exact location in a fuzzy area.We use maximum likelihood(ML)algorithm and centroid localization algorithm to estimate the location of the target.Because the ranging accuracy and reliability of radar are related to the distance(caused by signal fading),we propose an improved centroid location algorithm based on distance weight,which effectively improves positioning accuracy.