Research On Mutual Interference Between Millimeter Wave Radars For Autonomous Vehicles

Vehicle-mounted millimeter-wave radar is one of the most important sensors in autonomous driving systems.With the rapid increase in the number of vehicles equipped with millimeter wave radars,the problem of mutual interference between radars has become increasingly prominent,which seriously affects road safety of vehicles.Research on mutual interference between millimeter wave radars for autonomous vehicles is an important technical method and scientific basis for understanding the interference mechanism and realizing interference mitigation,and is a key part of ensuring safe driving of autonomous vehicles.Based on the systematic analysis of the research status of mutual interference between vehicular millimeter wave radars at home and abroad,the paper focuses on the relative position of radars,frequency reuse factors,effective interference density,transmitting power of interference radar and multipath effects,studied physical models and analysis methods based on random geometry,and proposed a radar average interference power framework based on the Poisson point process(PPP),which breaks through the limitations of the simulation environment in specific scenarios.Design static experiment and dynamic experiment plan to break the limitations of previous experience and simulation method;study the interference characteristics of vehicle-mounted millimeter wave radar in two-way single-lane conditions,obtain the interference distribution characteristics and the influence law of various factors on interference,and form a model analysis combined with physical objects Experimental research methods.The conclusions of the model analysis are consistent with the actual experimental results,indicating that the established model meets the actual requirements and the experimental results truly reflect the influence of mutual interference between radars.The main research contents of the thesis are as follows:(1)Combining the development of vehicle-mounted millimeter-wave radar technology and the related interference research background,the significance of the research on the mutual interference of millimeter-wave radars is clarified,and the research status and research status of mutual interference between autonomous driving vehicle-mounted millimeter-wave radars at home and abroad are systematically studied existing related problems.(2)The measuring principle and working characteristics of pulse Doppler radar are studied,and the ambiguity function,range resolution and Doppler resolution formulas are deduced.Aiming at the system structure and characteristics of pulse Doppler radar,the basic parameters of the radar are discussed,and the impact of detection performance is the major part.(3)In view of the main types of radars used and the random distribution of actual road vehicles,a random geometric model establishment and analysis method based on mutual interference between autonomous driving vehicle millimeter wave radars is determined.The characteristics of random distribution are studied.PPP is used to characterize the random distribution characteristics of cars and radars in a two-way single-lane situation.The normalized Gaussian waveform is approximated to the radiation pattern of the radar antenna,which improves the effectiveness of the radar signal.The vehicle-mounted radar interference model has been simplified,mainly studying the mutual interference between forward longrange radars,introducing frequency reuse factor and road vehicle density,and deriving the expression of average interference power.(4)According to the position relationship between radars and actual road traffic conditions,static and dynamic experiments are set up.The static experiment verifies the indirect interference of radar and the multipath reflection of radar signal,as well as the relative position relationship between radars and the influence of interference radar transmission power on mutual interference have been verified.The static experiment results are also valid for dynamic experiments.In the dynamic experiment,an automatic guided transport vehicle(AGV)equipped with millimeter wave radar was used to simulate the movement of the vehicle on the road,and three experimental conditions were set up for different lanes,different vehicle speeds and turning at intersections.