Global Ocean Analysis Offers Cost-Effective Alternative for Precise Seafloor Positioning

A study published in Satellite Navigation reveals that global ocean analysis products, specifically the HYbrid Coordinate Ocean Model (HYCOM), can achieve centimeter-level accuracy in seafloor positioning, offering a viable and cost-effective alternative to traditional in-situ sound speed measurements. This breakthrough is poised to reduce the financial and logistical burdens associated with marine geodetic surveys, particularly benefiting unmanned vehicles and long-term monitoring projects.

Accurate seafloor positioning is crucial for a range of scientific and industrial applications, from studying tectonic movements and earthquakes to exploring marine resources. The traditional Global Navigation Satellite System-Acoustic (GNSS-A) technique relies on costly in-situ sound speed profiles (SSPs), which are not only expensive but also challenging to collect due to varying ocean conditions. The study's findings suggest that HYCOM global ocean analysis derived SSPs can provide comparable accuracy without the need for these expensive and time-consuming surveys.

Conducted by researchers from the First Institute of Oceanography, Ministry of Natural Resources and Shandong University of Science and Technology, the study compared global ocean analysis derived SSPs with traditional in-situ and Munk empirical profiles. The results highlighted the global ocean analysis approach's superior accuracy, with horizontal positioning accuracy of 0.2 cm (RMS) and vertical accuracy of 2.9 cm (RMS), closely mirroring the precision of in-situ measurements. The Munk empirical profile, however, was found to introduce significant errors, rendering it unsuitable for high-precision applications.

Dr. Yanxiong Liu, the study's corresponding author, underscored the practical advantages of using global ocean analysis sound speed profiles over in-situ measurements. This innovation not only cuts costs but also enhances the accessibility of seafloor geodetic technology for both scientific research and industrial use. The implications of this study are vast, offering significant benefits for earthquake-prone areas, offshore industries, and deep-sea exploration by facilitating more affordable and frequent high-precision surveys.