Enhanced UXO Discrimination by Combining 3D Multichannel Sub Bottom Profiler with Magnetics

This paper shows the impact of a novel acoustic subsurface imaging technique on buried unexploded ordnance (UXO) clearance operations. In this study, the EdgeTech Buried Object Sonar System (eBoss) was employed at a proposed wind farm site in the North Sea. eBoss data was acquired at targets that were identified as potential UXO (pUXO) based on a geophysical magnetic survey conducted at an earlier stage. The examined targets are compared with the ‘ground truth’ of a subsequent ID&C campaign. We show that integrating magnetic and acoustic methodologies enables more advanced analysis and interpretation than using either technique alone. Acoustic imaging of subsurface targets enables the rejection of targets initially classified as pUXO in magnetic surveys, by inferring object size and shape from the acoustic data. In instances where acoustic images fail to provide definitive UXO identification, magnetic data offers additional insights about the target. Furthermore, the eBoss interpretation of buried targets facilitates magnetic modelling options that were previously unattainable. Thus, a survey integrating both eBoss and magnetics can provide more information compared to a survey relying on only one of the two, reducing the need of more costly identification techniques.