Design Of Small FMCW MIMO Radar System And Realization Of Imaging Algorithm

Multiple Input Multiple Output(MIMO)radar is a new radar system.It achieves higher target detection performance through a large aperture virtual array formed by multiple transmit antennas and multiple receive antennas.Due to the orthogonality of transmitted signals and different antenna arrangements,MIMO radar can achieve waveform diversity and spatial diversity.Therefore,it has many advantages,such as multi degree of freedom,more resolvable targets,high altitude resolution and anti-jamming.MIMO radar can overcome the influence of bad weather or insufficient illumination,and its antenna size is small,imaging accumulation time is short,and it has a strong target detection ability.The combination of MIMO radar technology and frequency modulated continuous wave(FMCW)technology can realize high-resolution range and angle measuring radar with small volume and low power consumption.In this paper,the hardware design and field imaging experiment of a small FMCW MIMO radar system in S-band are carried out,and the relevant theoretical algorithms are used to verify the experimental data.These work lay the foundation for the future marine ship monitoring,airspace UAV monitoring and other application scenarios.Based on FMCW MIMO radar system design and target imaging processing,this paper mainly completes the following work:Firstly,based on the basic theory of FMCW MIMO radar,this paper introduces the basic principles of range estimation and angle estimation of FMCW radar,and deduces the mathematical model of FMCW MIMO radar system,which lays a theoretical foundation for the hardware design and target parameter estimation of the system.Then,the overall scheme of a small FMCW MIMO radar hardware system is worked out.Each module of the system is designed according to the performance index,and the function test,error analysis and technical improvement of each module are carried out.In order to produce high quality FMCW signal,the designed radar system uses DDS excitation PLL structure as signal generator.In order to improve the radar resolution on the limited antenna and data channel,the time division multiplexing method is adopted.In the antenna array,four transmit antennas and four receive antennas are used to expand into 16 equivalent virtual antennas.In order to suppress the noise beyond the expected distance and improve the dynamic range of the receiver,an adjustable frequency band-pass filter and an adjustable gain amplifier are used in the signal conditioning circuit.Finally,the designed FMCW MIMO radar system is tested in the field,and the experimental data are obtained in the actual scene.The FFT beamforming algorithm is used to image the target.SPSF,CAPON and music algorithms are used to verify the highresolution range and angle measurement.The feasibility and algorithm performance of the radar system are evaluated and verified.At the end of the paper,the problems of radar system design and algorithm implementation have been summarized,and the problems still need to be solved in the next step are also pointed out.