一种采用高重复频率激光进行水声通信的方法

Method of Laser-Generated Sound with High Repetition Rate for Underwater Acoustic Communication

为研究空中平台与水下目标之间的激光声通信技术,提出了一种热膨胀机制下采用高重复频率激光进行水声通信的方法(重复频率法)。理论推导了高重复频率激光产生窄带声信号的过程,并通过实验测量进行了验证。利用高重复频率激光产生了频移键控(n-FSK)和多频移键控(n-MFSK)两种频移键控信号,结合现有激光器的技术指标,针对不同调制信号的水下通信距离、占用带宽、传输速率进行了分析计算,并与现有的方法(长脉冲法)进行了比较。结果表明,n-MFSK调制的传输速率比n-FSK调制的更快,频带利用率更高,但水下通信距离不及n-FSK调制;同为n-FSK调制,重复频率法的水下通信距离为1000m,比长脉冲法高40%,通信性能优于长脉冲法。

In order to study the technology of optoacoustic communication between aerial platforms and underwater objects, a method of laser-generated sound with high repetition rate for underwater acoustic communication is presented in a thermal expansion mechanism. The narrow-band acoustic signal is calculated and validated by experimental results, n-frequency-shift keying （n-FSK） and n-multiple frequency-shift keying （n-MFSK） modulated signals are generated in this method. The in-water range, bandwidth and data rate are analyzed for different modulation methods based on existing laser technology. The performance of modulation method with high repetition rate is compared with existing method （modulation method with long pulse）. The results show that this method can be used for communication of short range. Compared to n-FSK modulation, the performance of n-MFSK modulation is better on data rate but worse on in-water range. The in-water range of modulation method with high repetition rate is 1000 m, which is 40% further than that with lon~ Pulse for n-FSK modulation.