Aiming at problems that beamforming massive computing of 3D sonar makes complex hardware system which is difficult to realize

design 3D sonar system based on multistage beamforming.Based on large scale of transducer receiving arrays

the system utilizes distributed FPGA structure to achieve two stage beamforming

reduce 90 % of computing amount

compared with traditional beamforming.Rationality of the algorithm is verified by Matlab simulation.Tests underwater demonstrate that

within range of 50°horizontal and vertical coverage angle

3D sonar system is able to form 3D image with angular resolution of 0.39° and distance resolution of 2 cm.