针对开放式海洋环境通信特点,分析海气信道下行传输激光致声机理,提出基频可调激光跳频水下声通信方法,探讨激光跳频信号帧结构与信号传输特征。通过前导码间隔识别激光重频变化规律,研究水下传输的噪声信号与致声信号的频谱特性及分离方法,构建实验测量系统。实验结果表明,选择合适的下行光路光学结构可获得不同的致声能量效率。采用基频可调的ASK编码激光跳频通信能保证通信信息传输的安全性。在空海开放信道及弱信号环境下可满足数字信息的有效传送,为海洋通信提供新的技术途径。

According to the characteristics of marine communication,the mechanism of air-sea downlink transmission laser acoustic effect is analyzed, and the laser frequency hopping underwater acoustic communication method of tunable fundamental frequency is proposed. Frame structure and signal transmission characteristics of the laser frequency hopping signal are discussed while variation characteristics of the laser frequency repetition rate by the preamble interval being identified andthe spectral characteristics and separation method of underwater noise signal and acoustic signalbeing researched. The experimental measurement system is established. It is experimentally shown that different acoustic energy can be obtained by choosing the different optical structure of downlink optical path. The security of information transmission is ensured by using the laser frequency hopping communication method, which uses tunable fundamental frequency ASK modulation. In the environment of open air-sea channel and weak signal, the digital information effectively can be transmitted, and thus a new method for marine communication is provided.