相干瑞利散射海水水下温度测量技术的理论研究

海水水下温度的快速大范围测量是海洋监测的重要内容,在民用和军事领域都有着至关重要的意义,本文提出了采用相干瑞利散射方法测量海水水下温度的新方法:用宽带高速光电探测器接收本振激光和海水后向瑞利散射光相干产生的差频信号,进行傅里叶变换分析获取海水瑞利散射展宽谱,从而反演海水温度,首先从海水的热力学特性出发,对利用瑞利散射谱测量海水水下温度的基本原理进行了理论研究和软件模拟;然后对采用相干探测测量海水瑞利散射谱的测量方法进行了理论分析和软件模拟;在此基础上对瑞利散射海水水下温度测量精度进行了分析,得出当水体瑞利散射频谱半宽度测量精度为1 MHz时,测温精度约为0.35 K。

Theoretical study on measuring underwater temperature based on coherent Rayleigh scattering

The rapid measuring of the underwater temperature on a large scale is very important for marine monitoring, and it has vital significances in the civilian and military fields. In this paper, a new coherent Rayleigh scattering method to measure underwater temperature is presented. A wide-band photodetector is used to receive the heterodyne signal combined by the local oscillator laser and water Rayleigh backscattering light, and the water Rayleigh scattering spectrum can be acquired by transform analysis, then the water temperature can be obtained. Firstly, theoretical study and simulation are made on the basic principles of measuring underwater temperature based on Rayleigh scattering. Secondly, theoretical analysis and simulation are made on how to measure water Rayleigh scattering spectrum using coherent detection. Finally, the water temperature measurement accuracy based on Rayleigh scattering is analyzed, showing that for 1 MHz measurement accuracy of Rayleigh scattering spectrum half-width, about 0.35 K temperature measurement accuracy can be achieved.
Keywords： underwater temperature Rayleigh scattering coherent detection