The Application Of Spread Spectrum In Underwater Remote Control System

With the rapid exploitation of ocean and the need of national defense, underwater acoustic remote control system has been paid more and more attention recently. However, because of the complexity of underwater environments, especially the shallow sea channel with severe interference and multipath effect, it is relatively even difficult to realize reliable underwater acoustic remote control.Because of the ability of resisting multipath interference and low probability of interception, spread spectrum techniques are important ones used in underwater acoustic remote control system. According to the requirements of underwater acoustic remote control system, a direct sequence spread spectrum (DSSS) technique for underwater acoustic remote system was presented in this thesis. The purpose was to employ spread spectrum to overcome multipath and improve reliability of the underwater acoustic remote control system.The simulations of core algorithm as well as hardware and software implementation were the main parts of this thesis. Firstly, the fundamental questions of spread spectrum were discussed. Then the scheme of underwater acoustic remote control system was presented and the direct sequence spread spectrum was selected for the underwater acoustic remote control system. The model of underwater acoustic remote control system was designed and the performances were simulated with Simulink. At last, the system's hardware and software designs were introduced. The hardware was established based on DSP and FPGA, and the circuit interface and digital signal processing program of the receiver was designed.