Design And Realization Of High-speed Digital Receiving Element For Imaging Sonar

It is of importance that underwater acoustic imaging technology on the surface detection of seabed topography, the hull, the marine life and so on. It has the wide range of prospect and is playing an irreplaceable role in the field of underwater target detection, which will be paid attention day by day. This paper mainly studies a set of technologies in the imaging sonar system including data acquisition, storage and transmission, and has designed and realized the digital element of receiving system for imaging sonar.Firstly, the paper designs the hardware circuit, in which the A/D chip starts the analog to digital conversion, and the FPGA controls the sampling process as a core chip. Due to the high data transfer rate, the real-time transmission is realized by LVDS technology. The CF card storage circuit is also described in detail to save the primitive data acquired by high data transfer rate.Besides the hardware circuit, the paper has developed the software system that controls the data acquisition, LVDS transmission and the CF card storage by FPGA. The embedded soft-core processor could combine the different functional modules and receive unified commands, so the control process would shorten the development time and simplify the debugging process. It will achieve the purpose that it is accurate and effective to save and transmit the data in the acquired sampling rate.At last, the paper would introduce a simplified algorithm to realize the sector transformation in FPGA. According to the principle, it is easy to establish the simplified formula by trigonometric transformation, and convenient to complete the coordinate transformation with the arithmetic logic units in FPGA. This way could reduce the computation and raise the refresh rate in imaging sonar.According to the test, the hardware circuit and the software system designed by this paper, meet the system requirements and achieve the expected goals.