| With the rapid development of the automobile industry,the number of cars has increased year by year,and traffic accidents have become more frequent.Advanced driver assistance system can greatly reduce the occurrence of traffic accidents.The vehicle blind spot monitoring system is an important part of advanced driver assistance systems.It uses millimeter wave radar as the sensor to monitor the moving objects in the near blind area of the vehicle to assist driving and reduce traffic accidents.This papaer takes the blind spot monitoring of automobiles as the research object,and uses the Tri Core micro-controller and a dual-receiving 24 GHZ radio frequency chip from infineon as the hardware platform to carry out the design and implementation of infineon's Tri Core automotive millimeter wave radar system.According to the requirements of the project,this paper mainly researches and designs the automotive millimeter-wave radar system and waveform modulation,researches and optimizes the millimeter-wave radar angle measurement algorithms,and carries out hardware and software design based on the hardware platform and solves problems in system implementation.This article mainly undertakes the following works:1.Firstly,according to the technical indicators of the automotive millimeter wave system,the hardware and software overall scheme is designed,the slow oblique wave mode and fast oblique wave mode under FMCW modulation mode are analyzed,and the advantages and disadvantages are compared.Then,the determinants of distance,speed,and angular performance are explained through the derivation and simulation of theoretical formulas.In this paper,the fast oblique wave mode is selected as the modulation waveform of the system.2.The angle measurement method of automobile millimeter wave radar is analyzed and studied.First of all,the two-antenna phase angle measurement method is simulated and analyzed.Because the measurement effect is poor,the angle measurement algorithms of MUSIC and 3D-FFT under MIMO system are analyzed.Through the measurement of 3D-FFT,it is found that the angle measurement accuracy and angle resolution are high,but the amount of calculation is large.Then an improved multi-antenna 2D-FFT angle measurement method is proposed.Under the hardware platform AWR1642,compared with 3D-FFT angle measurement,it also has high precision and high angle resolution,and reduces the calculation of the system.3.The hardware and software implementation of millimeter wave radar system is studied.Firstly,the module circuit of hardware platform is designed,and the influence of parameter design and chip selection on distance and angle measurement accuracy is analyzed in the process of peripheral circuit and antenna design.Then the system software is designed and implemented,the program flow chart of the main circuit modules is given,and the specific realization flow of the system target angle calculation is analyzed.Finally,this thesis analyzes the process of radar data transmission and processing in the micro-controller.Because of the limited number of FFT accelerators and the large amplitude of short-range signal,the range dimension data is segmented to reduce the amplitude of the signal,so as to ensure that the real distance and speed of the target can be reflected after the Doppler dimension transformation.Finally,the necessity of segmented data interception is verified by experiments.4.The millimeter wave radar system is measured and analyzed.The distance and angle are tested according to the requirements of the index.The test results show that the detection range is more than 45 meters,the ranging precision is less than 0.1 meters,and the range resolution is 1.2 meters.The angle measurement accuracy in 3d B beam angle is less than 2.Finally,it can be seen from the road test that the single target and multi-target measurement at the far and near places are accurate,the whole system works stably,meets the requirements of system technical indicators,and achieves the actual expected effect. |
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