| In recent years,with the further improvement of semiconductor technology,millimeter wave radar has also been greatly developed.The demand of millimeter wave radar in anti-collision,security,unmanned driving and other fields is also increasing.The frequency modulated continuous wave(FMCW)radar has the characteristics of simple structure,high resolution and no distance blind zone,attracting more and more researchers' attention.In this paper,the sawtooth FMCW radar signal and signal processing algorithms are analyzed theoretically and simulated.The 24 GHz and 122 GHz radar chips are used to design and build FMCW radar test system,complete the design of radar signal processing software and display and control software,and carry out performance test.The main work is as follows:(1)The sawtooth FMCW radar signal and signal processing algorithms are analyzed theoretically and simulated,and an improved ordered-statistic CFAR algorithm is proposed to improve the calculation speed.Firstly,the theoretical research and formula derivation of sawtooth FMCW signal are carried out,and the performance of radar ranging and velocity measurement is analyzed,and the error caused by range-velocity coupling problem is given.Secondly,the signal processing algorithm is simulated and analyzed.The algorithm of moving target indicator is used to suppress the fixed clutter and improve the signal-to-noise ratio.On the basis of MTI,the fast Fourier transform equivalent Doppler filter bank is utilized for moving target detection to separate velocity information.Four CFAR algorithms including mean-level CFAR and ordered-statistic CFAR are designed to detect target,and according to the characteristics of the data in sliding window,an improved ordered-statistic CFAR algorithm is proposed to improve the calculation speed.The sorting method is used to achieve plots centroid,to eliminate the sidelobes and get the peak value of the signal.The real range of the target is calculated by the range-Doppler compensation formula.The principles of Multiple Signal Classification and root-Multiple Signal Classification angle measurement algorithms are given,and the performance difference is simulated and compared.Finally,the performance of FMCW radar target detection algorithms are verified by computer simulation.(2)The FMCW radar test system is designed and built by using 24 GHz and 122 GHz radar chips,evaluation board and PC,and the configuration and control of the chips are completed.Firstly,the composition diagrams of the radar chips are given,and the technical parameters and performance indexes of the radar chips and the evaluation board are introduced.Secondly,complete the design of FMCW radar test system,give the complete software composition and workflow,and design two test scenarios,including closed scenario and open scenario,to complete the construction of the test platform.Finally,the hardware of the evaluation board is set up,the UART communication protocols and the radar echo data format are studied,and the configuration of radar frontend is completed.(3)The radar signal processing and display control software are designed.Firstly,the overall software interface of the radar system is introduced,including the upper computer control system and the result display interface,and the functions are introduced.Secondly,the modules of UART configuration,parameter configuration,radar echo data receiving and saving,display and historical data playback in radar system display and control software and signal processing software are designed.The design ideas of the modules are analyzed and the software is programmed.(4)Experiment and test the radar system.On the FMCW radar test platform,the ranged measurement accuracy,speed measurement accuracy,maximum detection distance and signal attenuation degree are tested,and the test values are compared with the real values,and the test errors are analyzed. |
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