Reference Map of Safe Navigation Depth of Ships Based on AIS Data

Abstract

By mining massive AIS data, a new method for obtaining channel water depth information is proposed, that is, to construct a reference for safe navigation of ships; to clean and repair historical and online AIS data by data preprocessing method, to generate ship motion trajectory; to select the time, longitude and latitude of ship navigation area, to use K-means clustering algorithm. Cluster analysis of draft data during ship navigation is carried out to obtain ship classification in different safe navigation areas. BP neural network model is used to predict and fill the maximum draft information missing from AIS data. Historic ship trajectories are segmented and Spline interpolation method is used when the time interval of sub-trajectories is 10-20 minutes. The lost data are interpolated; the safe navigation depth area maps of the same kind of ships are constructed by convex hull, and the safe navigation depth area maps of different draft types are merged to obtain the merged safe navigation depth maps of ships; the merged safe navigation depth maps of different draft types are superimposed with the channel maps to obtain the reference of safe navigation depth of ships. The experimental results show that when the parameters of the clustering algorithm are set to 4, four types of ships can be obtained after clustering. The corresponding maximum draught ranges are 0.1-4.8, 4.8-6.6, 6.6-10.0, 10.0-13.0 m, and the corresponding draught of at least navigable ships are 1.8, 2.4, 3.3 and 5.0 m, respectively. The maximum draft is positively correlated with the draft of at least navigable ships; the reference of safe navigation depth of ships constructed covers 86% of the channels in the electronic channel chart and coincides with the Deep water part of the channel chart at 80%. Therefore, the reference of safe navigation depth of ships constructed can reflect the real situation of the channel depth and meet the navigation needs of different types of ships.