A groundbreaking study published in Satellite Navigation has demonstrated that global ocean analysis products, specifically the HYbrid Coordinate Ocean Model (HYCOM), can serve as a viable and cost-effective alternative to traditional in-situ sound speed measurements for achieving centimeter-level accuracy in seafloor positioning. This development is poised to significantly reduce the financial and logistical burdens associated with marine geodetic surveys, particularly for applications involving unmanned vehicles or long-term monitoring.
Accurate seafloor positioning is crucial for a wide range of scientific and industrial applications, including the study of tectonic movements, earthquake research, and the exploration of marine resources. The traditional method, known as the Global Navigation Satellite System-Acoustic (GNSS-A) technique, relies heavily on expensive in-situ sound speed profiles (SSPs), which are not only costly but also time-consuming to collect, with the added complexity of varying ocean conditions.
The research, led by a team from the First Institute of Oceanography, Ministry of Natural Resources and Shandong University of Science and Technology, compared the accuracy of SSPs derived from global ocean analysis with those obtained from traditional in-situ measurements and Munk empirical profiles. The findings were promising, showing that the global ocean analysis approach achieved horizontal positioning accuracy of 0.2 cm (RMS) and vertical accuracy of 2.9 cm (RMS), closely mirroring the precision of in-situ measurements. In contrast, the Munk empirical profile was found to introduce significant errors, rendering it unsuitable for high-precision applications.
Dr. Yanxiong Liu, the study's corresponding author, highlighted the practical advantages of using global ocean analysis sound speed profiles over in-situ measurements. This innovation not only promises to lower 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 potential benefits for earthquake-prone regions, offshore industries, and deep-sea exploration by facilitating more frequent and affordable high-precision surveys.
