Realization Of Phased Transmitting Based On FPGA And Simulation Research On 3-D Acoustical Imaging Algorithm

The three-dimensional (3-D) acoustic imaging technology plays an important part in the detection and recognition of the underwater target. Different from the 1-D and 2-D sonar, the 3-D one can obtain the underwater 3-D image, and confirm the 3-D coordinates of the target's distance, azimuth and elevation. Therefore, the 3-D imaging sonar provides more effective method and more wide information for these fields such as underwater target location and underwater vehicle collision avoidance.The phased linear array of transmitter and linear array of receiver make up a "T" shape. The dissertation finishes the controlling of phased array transmitter using FPGA. Besides, it simulates the 3-D imaging algorithm using MATLAB language. In the dissertation, we firstly study the phased principle, and realize the control for the 32-elements phased transimitter using FPGA. We carry on one phased scanning every 1 degree in the vertical direction, and the scanning area is between -10 degree and +10 degree. The result shows that:the error between the adjacent array elements'pratical time-delay and theory time-delay satisfies the design requirement.After that, the dissertation has a research on the phased array 3-D acoustic imaging algorithm, and also analyse the quadrature demodulation, amplitude weighting, near-field focusing, beanforming and sector conversion technology. What's more, we also simulated the 2-D and 3-D imaging algorithm for the point target as well as body target. The simulation results show that:the algorithm can image the point target and body target correctly, and the measured target location is the same as the setting parameter in the simulation.