激光空中探测水下目标的新方法研究

Study on a new method using remote laser to detect underwater objects

为了实现在空中利用激光技术对水下目标进行探测的目的,基于迈克尔逊干涉仪的基本原理,提出了一种从水面散射激光中获取水下声源信息的新方法。设计并实现了一套空中探测水下声信号的实验装置。实验结果表明:频谱分析图中的峰值频率即为水下声源的发声频率,系统能够实时探测发声频率在1 kHz^14 kHz的水下声源,且测量标准偏差小于7 Hz。该方法为航空遥感水下目标提供了一条新的技术途径。

A new method has been developed to detect real-time underwater acoustic signals with laser and a corresponding test system has been built. The experiment results prove that the method can be used to detect real-time underwater acoustic signals with a frequency between 1 kHz to 14 kHz. This test system consists of an underwater acoustic source, a precise optical detection device, and data acquisition and processing components. When the underwater a- coustic source generates sound causing fluctuation of the water surface, let laser beams irradiate the water interface from air, and the scattered light will carry frequency information of the acoustic waves. The precise optical detection device adopting basic principle of Michelson interferometer can detect change of optical parth difference caused by the water surface fluctuation, and achieve real-time information concerning audible frequency of the underwater acoustic source in the data processing system by means of demodulation. This completely innovative method provides a novel technical solution for aerial remote sensing of underwater objects.