The Underwater Sonar Transponder Based On FPGA

With the advent of more and more new weapons and underwater acoustic devices,in order to meet the needs of the developed underwater equipment and weapons to complete the water test and training,cooperating with the UAV for maritime target search,a sonar response system designed in the article is of great significance.The main research contents are as follows:Firstly,the underwater sonar target transponder system combines the theoretical research of the sound wave generation principle in each part of the underwater,and carry out a refined mathematical modeling of the target sound wave.Through the application of practical engineering and the research and analysis of acoustic mathematical model in the article,proposing a new system architecture design scheme,and using FPGA as the core control,which designs the amphibious working environment of the transponder(aquatic extension and underwater extension).The aquatic extension collects and distributes information from the exterior,and the underwater extension takes over and stores information.After launching,the underwater extension sends out the target simulated acoustic signal.The system is configured through three working states: self-test,configuration and training,cooperating with each unit circuit to make the transponder more timely,more stable and reliable to meet the technical requirements and improve work efficiency;the receiving front end of the underwater extension is equipped with the AGC control module to realize the signal frequency amplitude configuration,and the signal that meets the requirements is stably output to the subordinate machine for receiving;the magnetic circuit switching power supply is in a position to toggle automatically the MOS tube control in accordance with the three working states,and reduce the power consumption;the design method based on Fourier coefficient interpolation is used to estimate the frequency offset with high precision,improve the detection accuracy of the system and complete the underwater target simulation.Secondly,on the basis of the new design architecture,the transponder is divided into two parts: the superior machine and the subordinate machine,and the hardware and software of the system are designed.The hardware design mainly includes: PC interaction,data acquisition module,control module,fixed sound delivery module and magnetic circuit switching power supply circuit of superior machine,power amplifier and filter unit of subordinate machine,FPGA equipped with main control circuit,AGC control module,sound source level adjustment circuit,digital analog conversion module and power supply circuit design of subordinate machine,etc.On the basis of hardware design,the software design of the superior and subordinate machine of the system is carried out.The software part is mainly responsible for the parameter setting and issuance of PC interactive instructions,completing data traffic and calibration.The subordinate machine extracts EEPROM to store signal data,after DA conversion and power amplification,the transmitting transducer emits the target analog acoustic signal to realize the core function of the system.Through the hardware and software cooperation of the superior and subordinate machine,the joint debugging function of the whole machine is finally realized.Lastly,the technical test of the designed transponder is carried out and the test system is built.Through the signal test of the whole machine and the towing experiment of the boat on the lake,the experimental results are analyzed and summarized to verify that the transponder can stably and reliably realize the core function of underwater target acoustic signal simulation.