The Research And Realization Of Acoustic Target System Digital Homing Control

The acoustic target system designed in this paper is fixed, and it can test the guidance function and non-contact acoustic fuze function of the torpedo. The acoustic homing function of acoustic target system is to simulate the reflex echo of guidance signal of the torpedo, and the echo contains the reflex ability, Doppler shift, and pulse width of the moving submarine which is simulated. Those messages can guide the torpedo attack the fix acoustic target system, to test the guidance function of the torpedo. The acoustic fuze function of the acoustic target system is to simulate the scattering echo of the moving submarine to the non-contact acoustic fuze signal of torpedo, when the torpedo attacks the target, and trigger the acoustic fuze of the torpedo, to test the non-contact acoustic fuze function of the torpedo. Finally, achieve to test the guidance function and non-contact acoustic fuze function of the torpedo really on the sea.The paper mainly designs the hardware of acoustic homing parts in the system, does an in-depth theoretical analysis on several key technology of acoustic homing signal processing, and makes a simulation test by Bordland C++ Builder (BCB). In the hardware design, mainly design the FPGA acoustic homing parts, which contains input/output circuit of analog signal, AD/DA switch circuit, FPGA signal processing circuit, USB data interface circuit, and power module. FIR digital filter and direct digital frequency synthesizer achieve FPGA design using hardware description language (VHDL) by arithmetic. In theory, research and analysis the key technology of acoustic homing signal in depth, demodulation, measuring frequency, and memory send back separately use the arithmetic mean square deviation demodulation, measuring frequency by spectrum ratio method, and polyphase filter to analysis and process the acoustic homing signal, and make simulation to the arithmetic using MATLAB. In testing, make a simulation test which simulate the process of demodulation, measuring frequency, and send back to the acoustic homing signal, and compare the input signal of the acoustic homing signal and the output signal which have processed by the arithmetic, and validate the precision and feasibility of the arithmetic.