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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。
Aiming at the characteristics of open ocean environment communication, this paper analyzes the laser induced mechanism of down-air transmission in the air-sea channel, and proposes a method of underwater acoustic communication with adjustable base frequency and laser frequency hopping to discuss the frame structure and signal transmission characteristics of laser frequency-hopping signal. The variation of laser repetition frequency is identified by the preamble interval, and the spectral characteristics and separation method of noise signal and echogenic signal transmitted underwater are studied. The experimental measurement system is constructed. The experimental results show that different optical energy efficiency can be obtained by choosing the appropriate optical structure of the downstream optical path. The use of adjustable ASK baseband laser frequency hopping communication communication can ensure the safety of information transmission. The open transmission of air and the weak signal environment can satisfy the effective transmission of digital information and provide a new technical approach for marine communications.