Research On The Remote Control Receiving System With Long-distance Underwater Acoustic Signal

As an important stratagemical weapon, a new type mine, the long-range remote control mine, has become a hot research area in oceanic engineering. The efficient and reliable information transmission between transmitter and the mine greatly relies upon the development of long-range underwater acoustic information transmission techniques,so the analysis of the characteristics of underwater acoustic is absolutely necessary. The dissertation is devoted to the study on the characteristics of underwater acoustic channels for mine. Based on the comprehensive analysis on the characteristics of underwater acoustic channels, the research on the parameters of target sea area,the acoustic model, the characteristics of underwater acoustic transmission and the parameters of capability of long-range remote control receiving system is systematically conducted through theoretical analysis, computer simulation and testing of circuit. The main results and achivements are as follows:1. The propagation characteristics of underwater acoustic channels and their influences on long-range information transmission are studied thoroughly. Based on the sonar equation, the optimal frequency band is abtained. From the calculation about transmission loss,the source level is forecasted .Based on the random time varying channel theory, the fading characteristics of long-range underwater acoustic channels are analyzed. Then the important reference are provided for the optimal system design and technical parameters selecting of long-range underwater acoustic information transmission system.2. The underwater acoustic channel model based on ray theory is studied, and in combination with the system function of coherent multi-path channel, the method for underwater acoustic channel response prediction through eigenrays finding is obtained.3. The parameters of the long-range remote control receiving system are analyzed and simulated thoroughly, such as the signal to noise ratio(SNR) atthe receiver,the delicacy of receiver, auto-gain and band-width of the pass-band. Then the important references are provided for the design of long-range remote control receiver.4. According to the analyses of underwater acoustic channel and long-range remote control receiving system, we designed the long-range remote control receiver, including a low noise prefix-amplifier, a band pass filter and an auto-gain control circuit. Finally, the analog part of the receiver is tested and the frequency response of this receiving system is obtained..