Study On The Underwater Ultrasonic Detection Technology For Fuze

On the background of the new rocket depth charge multifunction fuze, the underwater ultrasonic detection technology for fuze is studied. The aim of this dissertation is to accomplish proximity fuze function by adding ultrasonic detection and control module without any modification to the structure of the existing depth charge.The traditional active sonar design theories are applied in medium and long range detection, and not all of them are applicable to the design of the underwater ultrasonic detection system for fuze. According to the short range detection characteristic and the analytical procedure of the traditional active sonar design theories, the underwater ultrasonic detection theories are studied in depth, including the mathematic models of the ultrasonic channel, emitting wave and echo detection. Furthermore the volume reverberation expression of the underwater ultrasonic detection is deduced, and the CW signal is designed for the emitting wave of the underwater ultrasonic detection system for fuze.Considering the case of the multiple rocket depth charge firing in salvoes, the underwater distributional model is established. The simulation result indicates: on the condition that the detection range of the underwater ultrasonic detection system for fuze is 15 m, the adjacent bomb interference probability is 13%. Furthermore the adjacent bomb interference problems are analyzed, and the results are as follows: (1) mistaking the adjacent bomb for the target; (2) mistaking the adjacent bomb's emitting wave for the echo; (3) mistaking the adjacent bomb's echo for the echo. The first and second adjacent bomb interference problems are solved by consummating the Doppler Shift method, and the Double-Gate Window Control method is put forward for resisting the third adjacent bomb interference.The overall design and parameters' selection of the underwater ultrasonic detection system for fuze are accomplished. The transducer array and circuit are designed. In order to improve the shock resistance and long-term storage ability, the P-51 piezoelectric ceramic material and epoxy insulation board are used to make piezoelectric transducers. The structure of the transducer array, which is assembled with 6 transducers, is optimized, and a new transmit-receive switching circuit is designed.The admittance measuring apparatus of piezoelectric transducer is made, and the transducers' admittance attributes are measured by using the self-made apparatus and the...