Design And Realization Of Synthetic Aperture Sonar Transmitter

With the increasingly frequent underwater detection activities,the underwater imaging performance becomes more demanding than ever before.As a new type of high-resolution water acoustic imaging technology,synthetic aperture sonar technology has been widely used.Due to the influence of temperature,depth,seasons,water area,gradient and other factors,underwater acoustic channel is a channel with narrow bandwidth and multipath effect.Sound waves are the only energy forms that can be propagated over long distances in underwater acoustic channels.Therefore,designing a high performance synthetic aperture sonar transmitter has become the focus of research.In this paper,based on the characteristics of sonar transmitter,the key issue in the process of sonar transmitter design is discussed by combining the relevant theory with experience.In order to meet the requirements of low power consumption,high efficiency and low distortion,the full-bridge Class D amplifier circuit is selected for the study.In addition,IRF2010 S MOS chip was used to achieve the stable and reliable driving circuit.Meanwhile,the principles of transformer design,considerations of design for anti-surge circuit and the design for transmitter cooling module,and protection circuit module are discussed in the paper as well.Since the sonar system emits a 60-100 kHz chirp pulse,a sufficiently large transmission bandwidth is needed in order to ensure the integrity and efficiency when a signal travels through water medium which means a transducer for broadband matching is required.A well matched circuit can effectively reduce the energy loss of the circuit,increase the load power,and expand the working bandwidth.The impedance characteristics of the transducer is very complex due to the fact that it changes with the frequency.So the impedance matching of the transducer requires a large amount of calculation.Therefore,in this paper,by using the computer software,the real-frequency matching technology is introduced to do a broadband adapter matching.This method only needs to provide transducers admittance S parameter file and set the relevant design parameters,which can be omitted from almost all the formula derivation and calculation.The resulting network is a practical available circuit and the simulation result is not significantly different with the actual deviation,so this study has a very practical value to the reality.In order to verify the performance of synthetic aperture transmitter,the transmitter power,surge current,power consumption,thermal performance have been tested,and the basic requirements were met.The results of the study are summarized at the final and the deficiencies in the simulation and design are pointed out.Moving forward,this paper comes up with the plans for improving the program as well.