Triton Navigation - Manual (Page 19)

Page 16
5.0 Bad Navigation Example - Bathymetry
5.1 Overview
The following example illustrates the need for multiple passes of filtering for a
bathymetry data file. The bad navigation present in this file is due to overhead
obstructions and is a common problem when working in harbors and river channels.
This data comes from a GeoAcoustics GeoSwath Plus interferrometric sonar and was
collected along the Seine River during a demonstration performed by the ECA group of
their Inspector USV (unmanned surface vessel). As seen in the image below, the Seine
River has many bridge crossings some of which are very wide and represent a significant
amount of time without receiving a GPS signal.
Looking at the navigation line in the lower image, the as the vessel passes under each
bridge the GPS signal is lost and the vessel trackline becomes erratic and the recorded
positions are not correct until the GPS signal is re-acquired.