Study On The Vehicle Forward Collision Monitoring And Warning System Based On Millimeter-wave Radar

In order to prevent and avoid vehicle rear-end collision accidents effectively,by analyzing the shortcomings of the existing anti-collision warning system,a forward anti-collision warning system based on 77 GHz millimeter-wave radar was designed based on the structural road and passenger vehicles.The main contents of this paper are as follows:1)The pre-collision condition of road traffic is analyzed,and the pre-collision avoidance environment is defined.Then the distance measurement principle of millimeter wave radar is expounded,and the parameters needed to obtain target information are deduced.On this basis,the methods of analog signal processing and digital signal processing are designed.2)The hardware requirements of anti-collision monitoring and warning system are analyzed,and the overall design of hardware circuit is completed.The signal processing modules such as filter and amplifier circuit,adjustable gain amplifier circuit and dc bias circuit are designed.The simulation results show that the signal processing module can filter out high frequency interference signals effectively,make the signals within the sampling range of AD,and improve the sampling accuracy.The design of CAN module and power module is completed,and the circuit board realizing the above functions is designed.3)On the basis of analog signal processing,a series of digital signal processing algorithms are designed.After the analog signal is converted into digital signal through AD sampling,the FIR low-pass digital filter is designed based on Filter Designer of MATLAB to filter out high-frequency interference signals.FFT transform is used to obtain the frequence of difference so as to obtain the target information.For environmental interference and possible false targets,CA-CFAR algorithm was used to eliminate them and carry out simulation verification.Under the condition of two-way two-lane traffic,road experiments are carried out,including static multi-target experiment,dynamic single-target experiment and dynamicmulti-target experiment.Error analysis is carried out according to the actual situation and detection situation.Experimental results show that the error rate of the system is less than 5%.4)On the basis of the structured road,the safe driving distance mathematical model is established according to the pre-traffic collision condition to judge the nature of the obstacle.The warning algorithm is designed with the buzzer of STM32.If it is a dangerous target,it will remind the driver to take measures.