| With the rapid development of millimeter wave devices,high-speed digital signal processors and LFMCW(Linear Frequency Modulation Continuous Wave)radar signal processing technology,millimeter wave radars are expanding in the field of civilian applications.The millimeter-wave LFMCW radar is small in size,simple in structure,high in range resolution and ranging accuracy.There is no theoretical blind spot in theory,which is suitable for close-range high-precision detection.In smart factories,Intelligent buildings,home care for the elderly etc,where indoor targets need to be detected,located,identified and tracked,compared to cameras,infrared,ultrasonic sensors etc,millimeter-wave radar in privacy protection,positioning accuracy,detection range.It has unique advantages in terms of environmental adaptability,especially the advent of single-chip millimeter-wave radar system,which promotes the application of millimeter-wave radar indoors.The millimeter-wave radar indoor target detection method has received great attention from relevant scholars.In indoor closed scenes,electromagnetic wave propagation has multipath phenomenon.In the past,the idea of dealing with multipath is mainly how to suppress multipath signals.Since multipath signals have certain observability,these multipaths information can be used to achieve single shots.The single-receiver antenna radar locates the target in the case of no beam scanning,improving the accuracy of target positioning under multipath conditions.This paper mainly studies indoor multipath utilization target detection method,and uses LFMCW MIMO(Multiple Input Multiple Output)radar signal processing technology combined with pedestrian motion characteristics to study,and builds a 77 GHz millimeter wave MIMO radar test system to carry out indoor pedestrian detection test.The main contents of the paper are as follows:1.The indoor target location method was studied.In the case where the size of the room is known,the mirror reflection light reversibility is used to determine the path of any secondary reflection.The geometric model of indoor electromagnetic wave multipath propagation is established,and the indoor target positioning method based on multipath utilization of single station radar is proposed.The Cramer's lower bound(CRLB)of the incident angle estimation of the phase interferometry under uniform linear array is derived,and the conclusion that the single-station radar multipath utilization target positioning accuracy is higher than that of the small uniform linear array radar is obtained.2.The LFMCW MIMO radar signal processing technology is studied.The basic principle and signal model of LFMCW radar are analyzed in detail.The techniques of moving target display(MTI),moving target detection(MTD),constant false alarm processing(CFAR),point condensing and improving radar ranging accuracy of LFMCW radar are studied.The algorithm is verified by simulation experiments.Then,the different aperture expansion methods and digital beamforming(DBF)algorithms of LFMCW MIMO radar are studied.Finally,the fast LFMCW radar waveform is analyzed.3.Designed a 77 GHz millimeter wave MIMO radar test system.First,the single-chip millimeter-wave radar system and the millimeter-wave radar front-end AWR1243 are introduced.Secondly,the 77 GHz millimeter wave MIMO radar test system scheme is proposed,and the design of FPGA(Field Programmable Gate Array)-based USB(Universal Serial Bus)3.0 data transmission module in radar test system is analyzed.Finally,the hardware design and FPGA programming of each module of the data transmission board are introduced in detail.4.The indoor target detection test was designed.The indoor pedestrian detection test was carried out by using the MIMO radar system designed in this paper.The measured data was processed by MATLAB software to verify the LFMCW radar signal processing algorithm,and the single-station radar multipath utilization location and MIMO radar antenna aperture location experiment were compared. |
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