Global Ocean Analysis Offers Cost-Effective Alternative for Seafloor Positioning

A groundbreaking study has demonstrated that global ocean analysis products can serve as a viable alternative to costly in-situ sound speed measurements for precise seafloor positioning. Published in Satellite Navigation, the research showcases the effectiveness of using sound speed profiles (SSPs) from the HYbrid Coordinate Ocean Model (HYCOM) global ocean analysis, achieving centimeter-level accuracy comparable to traditional methods. This advancement could revolutionize marine geodetic surveys by reducing both costs and logistical challenges, especially for unmanned vehicles or long-term monitoring projects.

Accurate seafloor positioning is essential for various applications, including tectonic movement studies, earthquake research, and marine resource exploration. The Global Navigation Satellite System-Acoustic (GNSS-A) technique, which combines satellite and acoustic measurements, has been the standard for achieving high precision. However, the reliance on in-situ SSPs has posed significant financial and operational hurdles. The new study, conducted by researchers from the First Institute of Oceanography, Ministry of Natural Resources, and Shandong University of Science and Technology, offers a solution by validating the use of HYCOM global ocean analysis products for GNSS-A positioning.

The findings reveal that global ocean analysis derived SSPs deliver horizontal positioning accuracy of 0.2 cm (RMS) and vertical accuracy of 2.9 cm (RMS), closely mirroring the results obtained from traditional in-situ measurements. This method eliminates the need for expensive sound speed field surveys, presenting a cost-effective alternative. Notably, the study also identified the limitations of the Munk empirical profile, which introduced significant vertical errors due to its oversimplified assumptions, making it unsuitable for high-precision applications.

Dr. Yanxiong Liu, the corresponding author of the study, emphasized the practical implications of these findings, stating that global ocean analysis sound speed profiles not only reduce costs but also broaden the accessibility of seafloor geodetic technology. This innovation is particularly beneficial for earthquake-prone regions and offshore industries, offering a more affordable means of conducting frequent, high-precision surveys. Furthermore, the method's compatibility with unmanned vehicles and deep-sea exploration opens new avenues for scientific research and industrial applications.

The study's publication marks a significant step forward in marine geodesy, providing a practical and economical solution to the challenges of seafloor positioning. By leveraging global ocean analysis products, researchers and industries can now access high-precision geodetic technology without the prohibitive costs associated with traditional methods. This development not only enhances our understanding of seafloor science but also paves the way for future innovations in marine exploration and monitoring.