Influence of Atmospheric Turbulence near the Sea Surface on the Performance of Shipborne Lidar

Turbulence near sea surface will cause the irregular flow of the whole atmosphere, lead to the distortion of the ship-based lidar echo, and destroy the stability of the system. Kolmogorov turbulence spectrum was used to analyze 1.55μm laser. The nonlinear optical effect of 1.55um laser in turbulent atmosphere is mainly analyzed, and its influence on the heterodyne efficiency, range resolution, carrier noise ratio and wind speed estimation accuracy of lidar system is analyzed. The results show that when
$C_{n}\ ^{2}$
exceeds 7.32×10
^-14
m
^-2/3
the heterodyne detection efficiency is 0, and the coherent detection mode is invalid. Since the value of the selected laser pulse width is much larger than the broadening range of turbulence, the influence of turbulence on the range resolution can be ignored. When
${C_{n}}^{2}$
greater than 2.67×10
^-12
m
^-2/3
, the CNR is lower than the system threshold for - 20dB, and the wind speed estimation accuracy is about 0.08m/s. In conclusion, when the turbulence intensity exceeds 2.67×10
^-12
m
^-2/3
, the coherent detection mode fails and the system cannot work. Finally, the simulation shows that the small aperture transmission is considered in the transceiver, and the adaptive adjustment device for large aperture reception can effectively reduce the impact of turbulence.