Determination of Absolute Coordinate of Underwater Control Point Taking Waves and Depth's Constraint into Account

To solve the problem that traditional underwater control point absolute positioning is time-consuming and laborious with low vertical precision, itis put forward that an accurate method with constraints of depth while taking waves into account to get absolute coordinate of underwater control point. Firstly, studiesarecarried outon the wave impact.And methods are put forward to determine the elevation difference between underwater points and the absolute elevation with GPS vertical values and the elevation difference. On this basis, methods are put forward, such asthe circle navigationwith depth's constraint to get single point's absolute coordinate, 2D free net adjustment with depth's constraint, integrated constraint adjustment,with accurate elevation difference, and 3D combined adjustment with accurate elevation difference. Finally, the experimental results show that the proposed methods can double the efficiency of traditional methods and improveprecision by one order of magnitude.