Experimental verification of seafloor crustal deformation observations by UAV-based GNSS- A

The Global Navigation Satellite System – Acoustic ranging combination technique (GNSS-A) is the only geodetic observation method that can precisely detect absolute horizontal and vertical seafloor crustal deformations on the centimetre scale. GNSS-A has detected many geophysical phenomena and is expected to make great contributions to earthquake disaster prevention science and geodesy. However, current observations obtained using a vessel and a buoy suffer from high cost or poor real-time performance, which leads to low observation frequency and delays in obtaining and transmitting disaster prevention information. To overcome these problems, a new sea-surface platform is required. Here, we develop a sea-landing unmanned aerial vehicle (UAV) system for GNSS-A. Sub-metre-level seafloor positioning is achieved based on real-time single-frequency GNSS data for an actual site. UAV-based GNSS-A allows high-frequency, near-real-time, and low-cost seafloor geodetic observations. It could be applied for high-frequency centimetre-accuracy observations using dual-frequency GNSS.