Symmetric Difference Positioning Model and Analysis of Sailing Circle Mode of Seafloor Control Points

Objectives The critical problem to be solved in the construction of a high-precision seafloor control network is to reduce the influence of systematic errors on the coordinate accuracy of seafloor control points during acoustic positioning.

Methods First, we analyze two positioning models: Non-difference and difference between epochs. Second, due to the change of sound velocity in seawater is affected by the long period term error and the short period term error, the system error caused by the shift in sound velocity in the measurement also has the characteristics of periodic change.

Results and Conclusions Based on this premise, a symmetric epoch differential positioning model was constructed. The results of simulation analysis and measured data analysis show that when the observation duration is an even multiple of the system error variation period, the symmetric differential positioning model can effectively reduce the influence of the system error on the positioning results. Still, when the observation duration is not an even multiple of the system error variation period, the model is no longer applicable.