Study On Vehicle-mounted Millimeter Wave Radar Forward Looking Imaging System

Although automobiles bring convenience to people,frequent traffic accidents pose a great threat to people's lives and property.In order to reduce or avoid the occurrence of traffic accidents,this paper studies the forward-looking imaging system of a vehicle-mounted millimeter-wave radar.It combines millimeter-wave radar which has the advantage of the all-weather and all-day working characteristics and array antenna imaging technologies to achieve the real-time,dynamic and high-resolution images of the scene in front of the car.It breaks through the observational limitations of human eyes and vehicle-mounted optical observation equipment and improves the ability to obtain road information on the platform especially in extreme weather,such as heavy fog,dust,and darkness,which ensures safety driving of the car.The main research work of this paper is as follows:Based on array antennas and combined the radar characteristics of the frequency modulation continuous wave system.The system adopts double-row array antennas for receiving and dispatching.Through the Multiple-Input Multiple-Output working mechanism,the geometric model of forward-looking imaging is established.The range resolution and azimuth resolution under the model is derived.According to the frequency-modulated continuous-wave radar transmitting FMCW signal,the forward-looking imaging echo signal model was derived.Based on the establishment of the vehicle front-viewing model,this paper applies the backward projection imaging algorithm and the two-dimensional wave number domain imaging algorithm to this model.Through the imaging simulation experiment of the point targets in the front area scene,it is shown that two imaging algorithms can obtain a two-dimensional high-resolution image of the observation area in front of car.Considering the actual situation,the movement of the vehicle platform,the vibration of the engine,the shaking of the vehicle body,and tortuous course will make the received echo data generate errors,resulting in the degradation of the image focusing quality.In this paper,the phase-gradient autofocus(PGA)algorithm is used to estimate phase errors and compensate the defocused image.Simulation experiments show that the algorithm can correct the defocused image to obtain a well-focused radar image.