Research And Design Of Automotive Collision Avoidance Radar

With the popularity of vehicles,it has become more and more important to avoid and reduce the occurrence of traffic accidents.Automotive collision avoidance radar is the most important part of the active safety system,which can effectively reduce the probability of accidents.Advanced driver assistance systems and driverless both are the future trend which are based on the automotive collision avoidance radar.However,the research of automotive collision avoidance radar in China is in the stage of development,and many technologies are not yet mature.Based on this,an Automotive Collision Avoidance Radar system is implemented in this paper,including hardware implementation of Automotive Collision Avoidance Radar system,and radar detection algorithm.Firstly,the principle of ranging and speed measurement of automotive collision avoidance radar is introduced in detail.LFMCW system is chosen for Automotive Collision Avoidance Radar system,which have many advantages such as high speed,simple modulation,small size,and so on.The principle of ranging and speed measurement of LFMCW radar is introduced based on the symmetrical triangular wave modulation method in detail,and the single-period and multi-period echo signals of symmetrical triangular wave are analyzed at the same time.The basic parameters of automotive collision avoidance radar system are given by the practical application requirements.Secondly,the hardware structure of collision avoidance radar system is designed and described in detail in this paper,including the receiving antenna and transmitting antenna,which center frequency and bandwidth is 24.125 GHz and 250 MHz,respectively.Combined with the RF front-end module and the transceiver antenna,the RF front-end module is designed to achieve the function of the reception and transmission of 24 GHz signals.The medium frequency signal amplifying and filtering circuit module is designed,which realizes the amplification and filtering of the intermediate frequency signal.Based on TMS320F28335 chip,the DSP signal processing board is designed to achieve data acquisition and processing.Then,it is found that the cross-matching method of changing the modulation waveform is more suitable for the automotive collision avoidance radar by analyzing the applicability of the commonly used two kinds of multi-target recognition methods.Therefore,an improved waveform cross-matching method is proposed,which can achieve the low false alarm rate,low calculation and high detection accuracy.Based on the proposed improved waveform cross-pairing method,combined with Fast Fourire Transform(FFT),signal accumulation and CFAR(Constant False Alarm Rate)processing,a detection method of automotive collision avoidance radar is designed to solve the information of target's characteristic.Finally,according to off-site testing,the proposed method is validated by the measured data.Simulation results demonstrate the main function of automotive collision avoidance radar,which can achieve the expected index.