Near-coincident mapping of sea ice from above and below with UAS and AUV

Since 2010 the SeaBED-class Autonomous Underwater Vehicles (AUVs) have advanced the 3D mapping of sea ice draft in both polar regions, revealing a new richness of thickness and morphology data previously hidden from traditional observation methods. The limiting factor for the complete 3D characterisation of sea ice has been the reduced area of surface measurements from TLS (100 x 100m) relative to the AUV survey (500 x 500m). Accordingly, we developed a low-cost fixed wing Unmanned Aerial System (UAS) to conduct photogrammetric surveys for Digital Elevation Model construction of the sea ice surface at the same time as the AUV missions were completed below. Here we detail this UAS system and discuss how this methodology can be improved and potentially evolve to medium-range (10 km) 'Beyond Visual Line of Sight' transect-based missions with the next generation of longer range AUVs.