Research On Key Technology Of High-precision Acoustic Positioning Of Seafloor Control Point

High-precision seafloor control point is the foundation and guarantee for constructing marine geodetic datum and providing marine positioning service.High-precision underwater acoustic positioning technology is the premise and key of constructing seafloor control point.However,due to the complexity of the marine environment,the positioning accuracy of seafloor control point is poor,which cannot meet the needs of practical marine applications.Therefore,focusing on sound speed error correction,gross error detection and systematic error processing,the main researches of the paper are following aspects:1.Developed a depth selection method of the data used in sound speed profile reconstruction.Aiming at the problem that the depth selection of the data required to reconstruct the sound speed profile by the empirical orthogonal function is not clear,taking the empirical orthogonal function variance contribution rate as the criterion.Based on the regional historical sound speed profile data,select the characteristic sound speed value and its depth,then reconstruct the whole sea depth sound speed profile.The feasibility of this method is verified by experiments.2.Research on the robust estimation method of seafloor control point positioning.Aiming at the inevitable gross error in the observation data,the weight selected iteration is applied to the positioning of seafloor control point.The IGG-III scheme is used to construct the equivalent weight function,and the positioning method of high-precision seafloor control point is studied.The experiments prove that the method can effectively resist the influence of gross error on the positioning accuracy,and has good stability and reliability.3.A seafloor control point positioning method based on Sage-Husa adaptive filter is studied.Considering the influence of the systematic error in the acoustic observation data,the systematic error is regarded as an random walk parameter,and the Sage-Husa adaptive filter is used to estimate it together with the position parameters,so as to realize the high-precision positioning of the seafloor control point.Simulation examples and measured data show that the method can effectively reduce the influence of systematic error and further improve the positioning accuracy.