Research On Key Technologies Of Seafloor Geodetic Control Point Calibration

The 21st century is the ocean century.The ocean accounts for 71%of the earth's surface area.It is an important space for human sustainable development and has become an important strategic goal for fierce competition in the world.Maintaining marine rights,developing marine economy and studying marine science requires high-precision marine geodetic reference;marine geodetic reference is the basic reference framework and important component of marine and island reef resources and environmental information,and is important for implementing the national marine power strategy.basis.At this stage,the construction and research of China's subsea control network is in its infancy.This paper is based on the national key R&D plan "Ocean Geodetic Datum and Marine Navigation New Technology" project,and carries out research on key technical issues of seafloor geodetic control point calibration school.The main research contents and results are as follows:(1)Summarize the domestic and international research progress of GNSS dynamic positioning technology,underwater acoustic positioning technology and seafloor geodetic control network construction,introduce the commonly used GNSS/Acoustic positioning system for seafloor geodetic control point calibration school,and analyze the system in progress.The main source of error in the seafloor control point calibration,as well as the method of eliminating or weakening the error and improving the calibration accuracy.(2)The different sea level control points calibration methods are introduced.The single difference positioning model between non-difference and epoch is studied.The robust least squares method based on weighted iteration is introduced into the seafloor control point calibration school.According to the measured data of the calibration test of the seabed transponder,the reliability and effectiveness of different calibration methods are verified,and the accuracy and application range of different calibration methods are analyzed.(3)The sound line tracking algorithm is studied.Using the deep sea measured sound velocity profile,the sound line bending at different incident angles and depths is calculated according to the layered equal gradient sound line tracking algorithm.Then,the sound velocity correction method in the seafloor geodetic control point calibration school is studied.The accuracy of different sound velocity correction methods in the seafloor control point calibration is compared and analyzed by simulation experiments.The sound line correction method is the most suitable method for correcting the sound speed of the seafloor geodetic control point calibration school,and the positioning accuracy reaches the centimeter level.