The Impact of Different Fitting Functions for Water Backscatter Waveforms on the Accuracy of Laser Sounding

Considering the physical process of laser sounding echo signal formation, a fitting method using exponential function to simulate water column contribution in Lidar waveforms is proposed on the basis of the existing Lidar waveforms fitting method. In order to compare and test the new method, pluralities of sets of simulated data sets are generated for further analyses. For each detectable echoes, the sea surface echoes and the seabed echoes are fitted by Gauss function, and the backscattering echoes are fitted by triangle, quadrilateral and exponential function. The results show significantly more accurate laser sounding estimates for the use of exponential function method compared with the use of a triangular function or a quadrilateral function to fit the column contribution. Moreover, exponential function is more suitable for fitting water column contribution in Lidar waveforms of different water quality and water depth. Meanwhile, the paper examines the impact of the volume scattering function at 180° on laser sounding estimates.