The Helmert Method for Improving the Adjustment Model of Underwater Terrain Surveys

In the article dasiaa method for detecting and adjusting systematic errors of singlebeam sounding data acquired in grid patternpsila (Liu et al, 2004), It had been discussed how to detect and adjust a systematic error along a sounding line by the discrepancies/disagreement at crossing points between the scheme main lines and reference sounding lines in obtaining seabed geographic information, and how to establish rank-defect adjustment model through least-square theory. Those methods in the paper are basic tools to process the data acquired in a grid pattern in obtaining geographic information of underwater terrain. In order to make the method available and practicable for obtaining seabed geographic information, by introducing the weight into the rank-defect model and changing its design matrix, the model has been improved in this paper to meet the actual requirements of processing the sounding data from different accuracy. The improved method has been tested by using the simulated data and the results show that the improved method can work well in processing the data from different accuracy and obtained the stochastic model of sounding data to assess the accuracy of water depth further.