Research And Implementation Of High-precision Ranging Algorithm For FMCW Radar Sensor

As one of the important equipment of industrial measurement,short-range detection radar has been widely used in different industrial fields such as liquid level meter,radio altimeter,vehicle collision warning system,precision positioning system and robot navigation and mapping.Among them,Frequency Modulated Continuous Wave(FMCW)radar,as a new non-contact ranging sensor,has the advantages of small size,high measurement accuracy,strong anti-interference ability,and can adapt to a variety of harsh working environments.Especially in the field of high-precision measurement,it shows high reliability and high accuracy,which is the key research object of industrial shortrange detection radar in recent years.Therefore,to improve the ranging accuracy of FMCW radar,this thesis studies the high-precision ranging algorithm of FMCW radar.The main research work includes:(1)Study the theoretical basis of FMCW radar.This thesis discusses the system architecture of FMCW radar based on sawtooth modulation,studies its measurement methods,and focuses on analyzing the key parameters that affect the ranging and velocity measurement performance.(2)Analyze and solve the error problem in the process of FMCW radar ranging.This part of the work from linear frequency modulation signal nonlinear,static clutter,spectrum leakage and fence effect,target detection,leakage suppression,doppler coupling and ambiguity six aspects of the error sources are analyzed and the corresponding solutions are given.Among them,to reduce the fence effect and improve the ranging accuracy,this thesis uses the improved FFT and Chirp-Z based on the characteristics of the energy center of gravity.Further,to solve the doppler ambiguity problem,the Fast/Slow Chirp waveform is designed in this thesis.By selecting appropriate effective signal repetition period and jagging code,the maximum acting speed of FMCW radar is greatly improved.(3)Establish the simulation model of FMCW high-precision ranging radar.The radar working environment,transmitter,transceiver antenna,receiver and signal processing part are modeled.Based on the model,beat signal is processed to verify the feasibility of the RF link and signal processing principle of the FMCW radar.The simulation results show that the improved high-precision ranging algorithm combined with FFT and ChirpZ based on the characteristics of energy center of gravity can achieve high-precision distance measurement.(4)Carry out high-precision distance measurement test.The FMCW radar designed in this thesis is developed and its algorithm is deployed.The test results show that the radar ranging error is improved from 15.20 cm to 3.00 cm by using the high-precision ranging algorithm,which confirms the advantage of the algorithm in the accurate range measurement.To sum up,this thesis takes FMCW radar as the research object,provides a set of solutions by studying different ranging error sources,verifies the effectiveness of highprecision ranging algorithm from modeling simulation and actual measurement analysis,and lays a solid foundation for the application of FMCW radar in high-precision ranging scenarios.