The Research Of Underwater Target Detection Based On Laser

As a kind of illuminant with high brightness and high collimation, laser is widely used in various fields. A new detection technology, combined with Laser detection and sonar technology, has received universal attention.Principles and development situation of laser-based sonar detection are described. One-dimensional model for the surface perturbation is derived, the reflection and refraction of sonar signal on water-air interface are studied, and the relationship between particle vibration velocity, displacement on water interface and underwater target radiated signal is given. On this basis, the principles of underwater target detection using direct laser intensity modulation method are described, the approximate detection ability of present laser-based sonar detection system is given. The manifestations of underwater signals with different source levels and frequencies in laser-based sonar detection are acquired by simulation.According to the principles mentioned above, a laser-based sonar detection system using direct laser intensity modulation method is designed, which includes optics, machinery and circuit these three main aspects. Modulated light is used as detecting signal in this system, photodiode area array is used as receiving module, which greatly improves the sensitivity and anti-interference ability of the system. A signal acquisition system for laser-based sonar detection system is constructed based on ARM embedded processor and real-time operating system.Experiments in the air and in an anechoic tank are both carried out lastly, the experimental data in calm water surface condition and violently disturbed water surface condition are acquired. The processing results prove the feasibility of surface perturbation detection based on direct laser intensity modulation method and the applicability of the laser-based sonar detection system designed.