The Research And Verification Of High Precision Ranging Algorithm Based On FMCW Radar

Non-contact accurate measurement has been widely used in industrial production,such as Structural Health Monitoring,liquid level measurement,moving target trajectory measurement,object deformation monitoring.As a non-contact high-accuracy measurement sensor,the microwave radar has better performance in practical applications.In this paper,the FMCW(Frequency modulation continuous wave)radar is taken as the research object.The purpose of this paper is to analyze and realize the accurate distance measurement of the short-range target.The main work is as follows:(1)From the view of beat signal acquisition,this paper briefly analyzes the three problems which distort the measured beat signal and affect the actual measurement accuracy in Chapter 2: VCO nonlinearity error,parasitic amplitude modulation interference and image frequency error.The corresponding mathematical models are established for the three problems.The paper analyzes the causes of three problems and proposes the corresponding solutions,which is conducive to actual measured datapreprocessing in subsequent chapters.(2)The high precision ranging algorithm for near-stationary target is studied in Chapter 3.A new algorithm is proposed to realize accurate frequency measurement by using the phase difference,whichcan determine the half-wavelength range ambiguity number of the target's location.The algorithm combines the advantages of frequency ranging and phase ranging and has the better performance in distance measurement.Finally,the upper algorithm is verified by Matlab simulation and radar actual measured results,which proves theaccuracy and effectiveness of the near-stationary target ranging algorithm.(3)The high precision range measurement algorithm for short-range moving target is studied in Chapter 4.Firstly,the influence of velocity on the parameter estimation of the beat signal is analyzed,including the velocity modulation of the frequency and the "distance-velocity" coupling in frequency measurement.According to these problems,anewly proposed algorithm of correcting the phase of the beat signal by using the initial estimation velocity is proposed.With this method the quadratic term in the phase of beat signal is eliminated and the beat signal is transformed to the single-frequency signal,which improves the measurement accuracy of frequency and phase.Finally,by using Matlab simulation and radar actual measurement results,it proves the accuracy and effectiveness of the algorithm dealing with short-range moving target ranging.(4)In Chapter 5,one-dimensional accurate ranging algorithm is generalized to three-dimensional and the three-dimensional target trajectory measurement method is studied.Firstly,the paper analyzes the influence of target's relative position on the measurement accuracy of the angle(such as the azimuth and pitch angle).Next,the paper derives the measurement formulas of the three-dimensional target trajectory measurement based on the one-transmitter and multi-receiver radar and multi-base station radar.The advantages and disadvantages of the two measurement schemes are compared and analyzed briefly.At last,the simulation is carried out by using Matlabto validate the proposed measurement schemes.In summary,this paper focuses on the above four aspects of FMCW precise ranging research,analyzes the main problems and proposes the corresponding algorithm or solution.By usingMatlab simulation and radar actual measured data,Itproves the effectiveness and high-accuracy of the proposed measurement algorithm when dealing the short-range target ranging based on FMCW radar.