Recent increases in the capability and reliability of autonomous underwater vehicles (AUVs) have provided the opportunity to conduct bathymetric seafloor surveys in shallow water (< 50 m). Unfortunately, surveys of this water depth may contain artifacts induced by large amplitude wave motion at the surface. The artifacts occur when an onboard pressure sensor determines the depth of the AUV. Waves overhead induce small pressure fluctuations at depth, which modulate the AUV’s pressure sensor output without causing actual vertical movement of the AUV. Since bathymetric measurements are made with respect to the AUV’s depth, these pressure fluctuations, in turn, modulate the measurement of the seafloor. The result is a periodic across-track, vertical offset of the seafloor profile (similar to a heave artifact sometimes common in surface vessel surveys). In this paper we describe our experience with the “Gavia” model AUV (Hafmynd EHF, Iceland) in a recent bathymetric survey during which wave action overhead induced such an artifact with a peak-to-peak amplitude as large as 1 meter. A method for removing the artifact as well as recommendations for modifications to the sonar, INS and AUV to mitigate the effect in the future are provided.
Journal or Conference Title
Canadian Hydrographic Conference (CHC)
Jun 21 - Jun 23, 2010
Quebec City, Quebec, Canada
Schmidt, Val E.; Raineault, Nicole A.; Skarke, Adam; Trembanis, Arthur; and Mayer, Larry A., "Correction of Bathymetric Survey Artifacts Resulting from Apparent Wave-Induced Vertical Position of an AUV" (2010). Canadian Hydrographic Conference (CHC). 793.