A typical modulated pulse bathymetric lidar system is investigated by simulation using a modulated pulse lidar simulation system. In the simulation, the return signal is generated by Monte Carlo method with modulated pulse propagation model and processed by mathematical tools like cross-correlation and digital filter. Computer simulation results incorporating the modulation detection scheme reveal a significant suppression of the water backscattering signal and corresponding target contrast enhancement. More simulation experiments are performed with various modulation and reception variables to investigate the effect of them on the bathymetric system performance.
Lidar is an important equipment for the accurate detection of underwater targets. In this paper, a compact
and remote-controlled lidar system is described. The system contains four modules which are Q-switch
Nd:YAG pulse laser module, photoelectric detector module, data collector module and remote-controlled
module. All of the modules are put into a hermetic container. The lidar system can be in operation under the
water and carried by an underwater carrier such as ROV (Remotely Operated Vehicle). The operator controls
the lidar and downloads the data from the system through a fiber. The system can automatically eliminate the
return signal due to the surface wave. The system has been used in underwater bubble detection. A brief
description of the lidar system and its operation is present in the paper. The experimental results of underwater
bubble measurement are discussed.