Study on the characteristics of underwater target laser echo based on pulse broadening

Background interference of impurity in strong water is the key factor restricting the detection distance and target characteristics of the weak target. Aiming at the problems of less echo characteristics and difficult identification of the characteristics of the underwater weak target laser detection, the paper studies the problem of the broadening of the laser echo pulse of the weak target under the background of strong water interference. A system of underwater weak target laser measurement and analysis is designed to suppress the near-field water scattering interference. The system can achieve matching adjustment among laser emission energy, laser beam angle and laser APD receiving gain. The detection performance of different underwater weak targets (small-scale metal, black rubber, low reflectivity reef, water grass, transparent plastic) was tested under different laser emission energy, different detection distance and different laser echo receiving gain. Through statistical analysis of data, the pulse width and material of the target of different underwater weak targets were obtained The relationship between the power of pulse laser, the distance between laser emission and target. The results show that the pulse broadening characteristics of the laser echo signal can be used to identify the weak target laser detection characteristics under the background of strong water impurity interference.