Data Processing And Time Series Analysis Of Seafloor Reference Station Network

The repeated observation of seafloor geodetic network can be used to study the seafloor plate technic and the process of marine disaster such as seafloor earthquake.In terms of submarine structure research,affected by observation condition,power supply and other factors,it is hard to achieve continuous observation for a long time.Japanese scholars proposed a method to deal with the seafloor station replacement by the connection measurement between the old and new stations to achieve the bias compensation of the discontinuous observation time series.But the methods of Japanese scholars cannot build dynamic reference frameworks,and the utilization rate of seabed data is low.Therefore,the research content of this article is:(1)Referring to the maintenance way of the terrestrial reference frame,and directly using the time series observation data of the seafloor geodetic network that may have discontinuities,and propose a multi station joint processing model of the seafloor geodetic coordinates based on the reference protocol epoch.The method is not only suitable for the geodetic dynamic reference frame maintenance,but also can be conducive to the implementation of fine quality control of the coordinate time series of each geodetic station in the regional network.The experimental results show that,the new proposed method is a substitute for the network center method,and the robust estimation results are more reliable.The average difference between the new method and the Japanese method’s annual velocity estimation of the seabed reference station is about 3mm/a,which can provide a new approach for maintaining the national seabed space benchmark.(2)When estimating the speed of a subfloor reference station,it is necessary to consider the occurrence of an earthquake.This article chooses to delete observation data affected by earthquakes.Experiments have shown that simple deletion of observation data cannot offset the impact of earthquakes,nor can it make linear velocity more accurate.(3)When studying the speed of the seabed reference station,it is possible to simultaneously study the motion speed of the land CORS station near the seabed reference station as a reference to further achieve the response analysis of the land reference frame and the seabed reference frame.The international earth reference frame has considered the nonlinear changes of the reference frame since ITRF2014,and has been updated to ITRF2020,providing a globally unified high-precision reference datum for geodesy,geoscience research and disaster monitoring.Compared with ITRF2014,the precision of ITRF2020 is higher.This article verifies that the prediction accuracy of ITRF2020 is better than that of ITRF2014,and the reasons why ITRF needs to be continuously updated.