The interplay between laser beam divergence and receiver field of view in airborne bathymetric LiDAR has a strong influence on spatial resolution, depth performance when measuring into the water, and vegetation penetration. Spatial resolution is ultimately limited by the laser footprint’s size on the ground, so a low beam divergence is usually preferable. Under certain circumstances, the capability of measuring through vegetation to the ground may be improved by using a larger laser beam divergence. The receiver field of view is usually kept as small as possible in order not to collect an unnecessary amount of background radiation. For bathymetric laser scanning, a large field of view enables the receiver to pick up more of the laser signal scattered on its way through the water column. In this paper, we systematically investigate the qualitative and quantitative effects when varying both parameters by operating a RIEGL VQ-840-G airborne topo-bathymetric laser scanner in different altitudes and with different parameter settings over waterbodies and forest areas.
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