Research On Car Anti-collision Radar Angle Measurement Technology

The advanced assisted driving system plays an important role in ensuring driver safety,and reducing traffic accidents.The millimeter wave radar is an important compo-nent that can detect blind areas in front of,behind and on both sides of the vehicle,provid-ing drivers with accurate obstacle information.This thesis will mainly focus on study-ing the modulation waveform and the angle measurement method of the anti-collision radar.On this basis,the simulation analysis of the factors affecting the accuracy of an-gle measurement will be carried out.On the ADI(Analog Devices Instrument)platform,the MMIC(Monolithic Microwave Integrated Circuit)transceiver,ADC(Analog Digital Converter)and DSP(Digital Signal Processor),the software and hardware of the vehi-cle anti-collision radar system are implemented to realize the target detection and angle measurement.This thesis is aimed to realize the automotive anti-collision radar angle measuring function,the main work is as follows:(1)In view of the shortcomings of traditional Linear Frequency-Modulated Contin-uous Wave(LFMCW)signal in velocity measurement and ranging,it is compared and analyzed to the merits and deficiencies of multi-target velocity measurement and ranging methods in two modes of LFMCW radar,Low Speed Ramp(LSR)mode and High Speed Ramp(HSR)mode.Based on the theoretical analysis,HSR waveform is selected as the modulation signal waveform in the system.(2)For the angle measurement methods in LFMCW radar system,it is studied and analyzed with the phase method and multiple-input multiple-output(MIMO)angle mea-surement methods.Based on that fundation,on one hand,the limitations of dual antenna angle measurement method is analyzed,on the other hand,the measuring range and ac-curacy of three antenna method and MIMO angle measurement method for LFMCW radar are simulated.According to the analysis of the experimental results,it can be seen that three antenna angle measurement method can achieve desirable angle measurement accuracy in this system.(3)The influence of several main factors on angle measurement accuracy is stud-ied.For the assumption that the inconsistence of channel amplitude and phase as well as the DC offset has an effect on the angular measurement results,a series of Monte Carlo simulation experiments are conducted for LFMCW radar respectively.By analyzing the experimental results,the validity of theoretical deduction is verified,which provides a significant reference for the further works on improving the accuracy of angle measure-ment.(4)By studying the implementation on hardware and software implementation of the system,the hardware schematic block diagram and software processing flow chart of each module are given here.On the ADI hardware platform,the vehicle anti-collision radar system is configured out and debugged,and then several groups of angle measurement experiments are carried out for different azimuth targets.According to angle measure-ment results,various factors affecting the accuracy of angle measurement are considered comprehensively.The final corrected angle measurement results are obtained,and the average correction error is less than 1~°.By measuring the moving target,the moving tar-get can be positioned correctly,and the point trace of its distance and velocity can be obtained.