Research On Key Technologies Of 77GHz Frequency Modulated Continuous Wave Linear Array Radar

With the continuous advancement of semiconductor technology,Frequency Modulated Continuous Wave(FMCW)radar technology is also making progress.Radar sensors are receiving increasing attention in civilian applications.In the field of radar imaging,compared to traditional optical cameras,lidar,and infrared radiation cameras,FMCW radar offers higher measurement accuracy and superior performance in smoke and fire environments.In FMCW radar,by combining it with Multi-input Multi-output(MIMO)array technology,the measurement accuracy can be significantly improved,thus greatly enhancing the imaging capabilities of FMCW radar.This study focuses on the hardware design and implementation of MIMO FMCW radar,as well as key technologies for indoor/outdoor personnel localization and point cloud imaging.This paper first introduces the hardware structure of FMCW radar and analyzes its principles at the hardware level.It then derives the formulas for range,velocity,and angle measurements.Finally,it provides an introduction to the Cell Averaging Constant False Alarm Rate(CA-CFAR)algorithm and point cloud imaging techniques.The introduction of MIMO technology enables FMCW radar to have higher angular resolution,making it highly promising and valuable in imaging radar applications.Furthermore,we introduce the principle of MIMO virtual aperture technology and analyze how it improves angular resolution.We then analyze the transmission method of Time Division Multiplexing Access(TDMA)orthogonal waveforms and derive the signal processing model for TDMA-MIMO.Finally,we establish index parameters for near-field indoor/outdoor personnel localization and point cloud imaging targets,conduct research and design on MIMO antennas,and design a linear array antenna with a spacing of 1.28λ.Regarding hardware implementation,this paper first conducts a survey to select the appropriate solution and ultimately chooses an integrated chip solution.A point cloud imaging scheme is built around the AWR1443 radar sensor.Based on the antenna specifications,a microstrip line array antenna for 77 GHz FMCW radar is designed.Subsequently,in accordance with the specifications of the MIMO FMCW imaging linear array radar system,schematic and layout designs of various components are completed,referring to the evaluation board provided by Texas Instruments(TI).Finally,in the experiments on indoor/outdoor personnel localization and point cloud imaging using MIMO linear arrays,signal processing and optimization algorithms for linear array millimeter-wave radar are studied.To overcome the drawbacks of the small amount of point cloud data received by millimeter-wave radar,limited measurement range,and susceptibility to reflection interference,the CA-CFAR algorithm is employed in conjunction with a two-dimensional rotating platform to extract more point cloud data.Outdoor experiments with and without smoke are conducted to validate the system,yielding satisfactory overall results.