| In recent years,with the increasing number of cars,Traffic accidents occur frequently,resulting in loss of life and property in society and families.Automobile anti-collision radar system can effectively warn and reduce traffic accidents.Therefore,the automobile anti-collision radar system has a very high application prospect and research value.This paper studies the signal processing method of automobile anti-collision radar system,proposes a new processing scheme,and develops a prototype of automobile anti-collision radar.The main work of this paper is as follows:(1)Modulation mode of automobile anti-collision radar system.The common modulated modes of radar include pulse modulation,linear frequency modulation and multi-frequency shift keying modulation.Mathematical models are established for the working principle of velocity measurement and ranging respectively,and the advantages and disadvantages of the three waveforms are compared.The essence of multi-frequency shift keying modulation is the combination of frequency shift keying and linear frequency modulation to solve the problem of false targets in linear frequency modulation.(2)Research on radar intermediate frequency signal processing methods,including target frequency estimation and target detection.Target frequency estimation part adopts FFT phase and chirp-z transform method of combining the optimized frequency estimation,first through all phase FFT to find target spectrum peak position,followed by using of chirp-z transform to subdivid spectral peak frequency band around and effectively reducing the frequency measurement between the actual frequency and solve the traditional fast fourier transform " spectrum leakage " problem.In the target detection part,several common constant false alarm detection algorithms are comprehensively analyzed.Considering the complex environment of multi-target detection,the ordered constant false alarm detector is finally adopted.In addition,the ordered constant false alarm detector is deeply studied.(3)Design of automobile collision avoidance radar system.Hardware design includes power circuit design,intermediate frequency signal filter,amplifier circuit design,CAN communication circuit design.According to the system index,complete the parameter setting of specific component.The software design is divided into the host program design and the slave program design.The overall program realizes the data collection of road condition information,completes the target speed measurement and ranging,judges the road condition and prompts the driver for the next step.(4)Actual scene test of the system.Indoor system speed measurement and ranging function test,collect the data collected by the upper computer,speed and distance simulation verification through MATLAB platform;Test the system's outdoor speed measurement and ranging function as well as target recognition ability,and observe the upper computer's video window in real time.According to the data statistical analysis,the detection distance of the system is about 60 m,the false alarm rate is 1.98%,the alarm leakage rate is 3.49%,the average error of the system is 5.60%,and multiple targets can be detected at the same time. |
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