The efficient self-checking method for the seafloor geodetic network

Abstract

The traditional check and calibration of the seafloor geodetic network mainly adopts GNSS-Acoustic technology to check seafloor control points one by one, which is both costly and time-consuming. To address this issue, two self-checking methods for the seafloor geodetic network, the Max-Gap (MG) method and the Stepwise-Forward (SF) method, are proposed based on the mutual ranging between seafloor control points. The MG method combines the free network adjustment model of the seafloor geodetic network with the θ2 criterion, and the SF method combines the adjustment model under the constraint of known points with the optimal control point combination-step forward test based on TOPSIS method. After the self-checking is completed, the stable points in the test results are taken as the constraint, the distance between control points is taken as the observation, then the recalibration of the changing points can be realized through the whole network adjustment model. The simulation experiments show that the MG method is ideal for the seafloor geodetic network with fewer control points. It can accurately find the seafloor control points with centimeter or decimeter displacement. The SF method is suitable for various types of seafloor geodetic networks. It can accurately find the centimeter-level or decimeter-level displacement points in geodetic networks with fewer or large number of control points, and when the acoustic ranging error is less than the displacement, the correct ratio of which is more than 95%. The field experiment shows that the difference between the self-calibration results based on the proposed method and that of the circle-sailing method is millimeter, indicating that the proposed methods are high-accuracy.