  Aliased seabed echoes, also known as "false bottoms" or "shadow bottoms", are
a form of echogram corruption caused by seabed reverberation from preceding
pings coinciding with echoes from the current ping. These aliases are usually
either avoided by adjusting the survey parameters, or identified and removed by
hand - a subjective and laborious process. This paper describes a simple
algorithm that uses volume backscatter and split-beam angle to detect and
remove aliased seabed using single frequency, split-beam echo sounder data
without the need for bathymetry.
