Numerical simulation of backscattered echo signal of lidar in near field of water

Abstract In the near-field underwater detection of lidar, the low accuracy of time integration model leads to a lot of noise and a low signal to backscatter ratio during target signal extraction. Aiming at this problem, this paper divides the water into thickness units according to the scale time of the AD acquisition card, and establishes a near-field water echo model of lidar called distance layer summation model(DLSM). According to the underwater optical transmission theory, this paper establishes the formula for the time delay of the echo signal of the water with the system angle. The pulse width error of the calculated and measured results is 0.55ns. The experimental results after normalization show that compared with the time integration model, the pulse width percentage error of the model in this paper is reduced by 18.7 %, the root mean square error is reduced by 0.04, and the signal to backscatter ratio is increased by 8.74 dB. The simulation results of the model in this paper are more consistent with the measured water waveform, which can lay the foundation for the subsequent work of water backscatter suppression and target echo signal extraction.