Research And Implementation Of Wideband High Resolution Frequency Synthesizer

In recent years,advanced driver assistance system has developed rapidly,and high reliability driving behavior decision depends on high precision,wide field,long distance radar.Millimeter wave radar plays an important role in driver assistance systems because it is adaptable and can work all day.It is of wide frequency band,narrow beam,good directivity,and high spatial resolution,which is widely used in driving warning,auxiliary control,vision improvement and other scenarios.However,due to the limitation of cost and algorithm performance,the angle resolution of radar is not high enough,which restricts the behavior decision of driving assistance system.To solve the above problems,this thesis adopts sawtooth frequency modulated continuous wave signal,establishes the echo model,focuses on the research of the virtual aperture angle measurement algorithm of MIMO radar,and verifies the feasibility of the angle measurement algorithm based on AWR2243.Millimeter wave MIMO radar usually adopts sawtooth frequency modulated continuous wave signal.After mixing and low pass filtering the echo signal,the beat baseband signal can be obtained.In this thesis,an array echo model is established.The multi-channel baseband echo signal is sampled to form a 3D data,which can be processed to obtain the distance,velocity,and angle information.This thesis presents an angle measurement algorithm based on compressed sensing.The perceptual matrix is constructed by meshing the detectable area.Gaussian random matrix is used to sample and compress the echo signal to form the output signal and realize the sparse reconstruction of signals.The simulation results show that,compared with the traditional method,the algorithm can improve the angle resolution,effectively suppress the high side lobe and gate lobe by the traditional method,and reduce the false alarm probability.Due to the high computational complexity of this method,a compression sensing angle measurement method based on MWC is proposed.This method combines compressed sensing theory with MWC.The signal is sampled and compressed by MWC.The output signal is equivalent to the weighted sum after segmentation in space domain.The signal is reconstructed by OMPMMV algorithm and the target information can be estimated.Compared with the traditional method,the angle resolution is improved.It is a trend to improve the resolution of azimuth and elevation angle by using MIMO virtual sparse surface array.A virtual transformation angle measurement method based on block space smoothing is proposed to further improve the angle resolution.The planar array is partitioned into blocks for spatial smoothing.Then the interpolation method is used to transform the non-uniform planar array into a uniform planar array with a larger aperture.And high-resolution angle measurement can be realized.Simulation results show that,compared with traditional method,the angle resolution is increased to 2-3times,and the ratio of main and sidelobe is improved about 11 d B.Finally,based on the AWR2243 evaluation board,the data received by the radar are transmitted to the computer,and the feasibility of the two algorithms,the compressed sensing Angle measurement algorithm and the virtual transformation angle measurement method of block-space smoothing,are verified by data processing.