Design And Implementation Of Millimeter Wave Vehicle Anti-collision Radar Signal Processing

With the rapid growth of the national economy and the increase in the number of private cars,people have put forward higher requirements for automobile performance and safety.Car anti-collision radar targets other vehicles on the road and the surrounding environment,and uses electromagnetic waves as a detection carrier to measure the distance,speed and angle of the target vehicles on the road.Millimeter-wave radar is more adaptable to climate than traditional sensors such as lidar,ultrasound,and cameras,and has gradually become the sensor of choice.Most traditional anti-collision radars for cars use triangle wave frequency modulation,and there are many false targets under multi-targets.In recent years,anti-collision radar has transitioned from triangular wave frequency modulation to sawtooth wave frequency modulation.Although sawtooth wave frequency modulation has solved the problem of false targets,it also brings new problems such as Doppler ambiguity and distance-speed coupling.This paper focuses on the signal processing of automobile anti-collision radar,and analyzes the problems of sawtooth wave and triangle wave FM in practical use,research on methods to improve measurement accuracy,and FPGA signal processing implementation.The main work of the thesis is:Firstly,the automobile anti-collision sensor is introduced and compared,and the background and significance of signal processing research are introduced.Continue to combine the basic principles of common frequency modulation methods(triangular wave and sawtooth wave)of LFMCW radar to describe the current problems and difficulties in signal processing of anti-collision radar of automobiles.Finally,the knowledge of MIMO angle measurement principle,radar power calculation and constant false alarm detection are introduced to lay the foundation for subsequent research.Secondly,This paper model and simulate the actual problems encountered in the sawtooth frequency modulation,analyze the factors that affect the resolution and accuracy,and focus on the derivation and simulation of distance-velocity coupling,spectral leakage,channel amplitude and phase inconsistency,and Doppler phase deviation..After that,the methods for improving the accuracy of spectrum estimation are described and compared,and finally the safety distance and early warning strategies are studied.Finally,the function,working sequence and implementation principle of each module in the FPGA implementation process are described.Based on the introduction of functions and timing,each module is simulated using Modelsim.Finally,the design of the signal processing system is verified through the experiments of stationary targets and moving targets.The experimental results show that the energy center-of-gravity calibration method can effectively improve the range and speed accuracy of radar.