Real-Time Imaging Technology Of Multi-Beam Synthetic Aperture Sonar Based On DSP

Imaging sonar can obtain rich and intuitive underwater information,and has been a research hotspot at home and abroad for ocean exploration.Among them,multi-beam synthetic aperture sonar combines the technical advantages of multi-beam bathymetric sonar and synthetic aperture sonar,which not only can achieve full coverage 3D acoustic imaging underwater,but also has the same image resolution as synthetic aperture sonar in the trajectory direction,and has a wide range of application prospects.Compared to other imaging sonars,multi-beam synthetic aperture sonar are mostly in the theoretical simulation or post-processing stage due to the complexity of imaging algorithms and the large amount of calculations,and no real-time imaging systems have been realized.Based on this,in order to solve the practical problem of multi-beam synthetic aperture sonar,this paper,with the support of the National Natural Science Foundation of China-Shandong Province Joint Foundation Project,investigates the real-time imaging technology of multi-beam synthetic aperture sonar on the basis of existing theories and realizes it in real time based on multi-core DSP.Firstly,from the basic principles of multi-beam bathymetric sonar and synthetic aperture sonar,the imaging principle of multi-beam synthetic aperture sonar is studied,its technical advantages and imaging resolution are analysed,and the application of multi-subarray technology in multibeam synthetic aperture sonar is introduced for the problem of spatial sampling limitation,and the signal echo model under its two-dimensional surface array detection is given.Then,according to the principle of multi-beam synthetic aperture sonar detection,the multi-beam synthetic aperture 3D imaging algorithm is studied.The synthetic aperture pointby-point imaging algorithm is used in the track direction,and the beam formation process is carried out in the horizontal direction.The imaging effect is verified by experimental echo data.Finally,this paper designs a real-time signal parallel processing scheme for multi-beam synthetic aperture imaging algorithms based on the multi-core DSP TMS320C6678.The development of multiple functional modules of the DSP,including peripheral interfaces and internal unique resources,gives a real-time signal multi-core parallel processing processes,and the program was optimised in many ways,after real-time analysis,to achieve the system realtime processing requirements,real-time imaging of multi-beam synthetic aperture sonar achieved for the first time.Secondly,a pool test of the whole sonar system was also carried out,and a pool test scheme was designed.After the analysis of the imaging results,the effectiveness and real-time performance of the multi-beam synthetic aperture sonar real-time imaging scheme designed in this paper were verified.