Design And Algorithm Research Of High-Precision Sensing Imaging Array Based On Mobile Terminal

At present,smart terminal devices are characterized by miniaturization and mobility.However,due to the limitations of volume and power,the dimensions of information perceived by these intelligent terminals are less.The most common perceptual imaging equipment on the existing mobile terminal is optical sensor,which is flexible in arrangement and easy to use,but it is easy to be affected by optical path occlusion and has requirements for the use environment.Electromagnetic wave-based sensors(radar)can avoid the above problems and perceive more dimensional information.Therefore,in this thesis,we focus on the high precision perceptual imaging radar technology based on mobile terminal.Aiming at realizing near-field 3D imaging and reducing the design cost of the array,the near-field 3D imaging algorithm under real aperture conditions,the sparse MIMO array structure and the corresponding near-field imaging algorithm are studied,and the simulation imaging of the relevant scene is carried out.The specific works are summarized below:1.The problem of near-field 3D imaging under real aperture conditions is studied.Firstly,taking the common intelligent terminal as an example,the shape and size of the array are determined,and then the signal frequency band is selected according to the attenuation in the process of signal propagation.Then combined with the specific array format,the influence of the aperture transition effect on the imaging results in the near field is analyzed,and an imaging method that can avoid the influence of the aperture transition effect is proposed.Meanwhile,in order to improve the efficiency of the algorithm,based on the idea of FFT acceleration calculation,a near-field 3D imaging algorithm based on FFT is studied for linear frequency modulation signals.Finally,a simulation experiment was carried out on the algorithm,and the results showed that the algorithm can obtain correct three-dimensional imaging results,but the final computational efficiency is limited by the relationship between the array element spacing and the lateral resolution.2.The near-field 3D imaging of MIMO array is investigated.First,the reason why the time-division MIMO array cannot be directly equivalent to a uniform virtual array under near-field conditions is analyzed.Then a time-division MIMO array near-field 3D imaging algorithm is proposed based on this problem,which can complete the near-field 3D imaging of the MIMO array.The imaging results are accurate.The MIMO array and the SIMO array are used to perform 3D imaging of a single point target and multiple point targets in close proximity.The effectiveness of the MIMO array near-field 3D imaging algorithm is verified by the above simulation.The relationship between the imaging performance and the distance between the target and the array is analyzed and the root cause is found.In order to solve the problem that the imaging performance cannot meet the requirements due to the distance between the target and the array is too small,two solutions are proposed,namely aperture scaling and sidelobe interleaving.The effects of the two solutions are verified by simulation.Finally,the simulation of MIMO array 3D imaging is carried out for a more practical scene,and the feasibility of the array and algorithm is verified.Furthermore,for the array close range imaging scene,the imaging scene is set very close to the array,the 3D imaging results of the large aperture MIMO array and the 3D imaging results after using the aperture scaling method are obtained by simulation,which verify the effectiveness of the aperture scaling method.3.The sparse MIMO array design is considered.A sparse MIMO array structure is proposed,including the design idea,the specific array structure and the expansion mode.the proposed array is compared with the traditional MIMO array and the existing sparse MIMO array.The results show that the imaging effect of the proposed sparse MIMO array is better than that of the existing sparse MIMO array,which is similar to that of the traditional MIMO array,and the number of elements and channels of the proposed array is much less than that of the traditional MIMO array.Finally,three-dimensional imaging of the scene was performed using the proposed sparse MIMO array,which verified the usability of the array in scene imaging.