A Novel Approach for Autonomous Densely Spaced Acquisition of Buried Objects in Intertidal Environments—Field Examples From Avaldsnes, Norway

Abstract

Underwater archaeology relies on expensive and time‐consuming invasive methods for identifying and excavating objects buried in the seabed or identifying layers in shallow and intertidal environments. Especially shallow and intertidal environments are challenging due to locally high levels of sedimentation that offer good conditions for preserving organic material, that is, archaeological objects, in stabile and low‐oxygen environments. We present a system capable of dense (25 cm × 25 cm) survey coverage that enables nondestructive decimetre‐scale visualization of buried objects and sedimentary layers lying in the subsurface. The system comprises an autonomous surface vehicle (ASV) equipped with a single‐channel 2D Chirp sonar. A description of the vehicle design is presented, and results from five field tests demonstrate the ability of the system to collect high‐resolution acoustic data in a variety of shallow water environments. The system shows an example of the linearized zero offset reflectivity inversion dataset, visualizing a known buried shipwreck from the medieval period in Avaldsnes, Norway. The ASV system holds global implications as it can serve as a noninvasive first‐stage survey in sensitive heritage or archaeological areas. Areas where traditional methods are challenging, or invasive methods are dissuaded.