Acoustic Corer with Synthetic Aperture Sonar for Subsurface Imaging of Buried Obstructions in the Hudson River

In support of the Hudson River Ground Stabilization (HRGS) project, Kraken Robotics conducted a sub-bottom survey using its advanced volumetric imaging system, Acoustic Corer (AC), to identify buried obstructions that could impact construction. The survey was performed in shallow, dynamic water conditions within the Hudson River, adjacent to Manhattan, an area characterised by strong currents, soft silt, and anthropogenic sediment layers. A total of 102 AC deployments were completed, each using a client-designed pile and strut assembly for system stabilization and post-processing accuracy. The AC, equipped with synthetic aperture sonar (SAS) technologies including high-frequency chirp, low-frequency chirp and parametric sources, generates a 14 m diameter volumetric “acoustic core” capable of imaging buried objects and stratigraphy with high spatial resolution. The goal was to locate hazards such as debris or construction remnants beneath the riverbed. Data were processed using Kraken’s proprietary software, ZoomSpace. Notably, a continuous linear anomaly running north–south across the survey area, suggestive of a cable or pipe, was interpreted as a buried obstruction and subsequently confirmed through diver excavation to be part of a mooring line. Despite environmental complexity, the AC provided high-resolution, volumetric sub-bottom imagery, demonstrating its effectiveness for risk mitigation in urban, shallow-water environments.