The Multi-directional Crossing-line Channel Analysis Method Based On AIS Data

Channel is an important traffic environment for ships.The channel analysis is an important prerequisite for ship risk assessment,and an indispensable part for improving the efficiency of shipping management.With the development of shipping industry,AIS(Automatic Identification System)has been widely used in various ships because it was able to automatically identify the real-time status information of the ship.Vector data in AIS was also preserved with the upgrade of modern storage devices,which promoted more accurate channel analysis,but it also increased the complexity of statistics at the same time.In recent years,statistical analyses of channels based on AIS data emerged in an endless stream.In order to reduce the complexity of ship statistics,crossing-lines were introduced into channel analysis,and the data of equidistant crossing-lines were taken as samples to analyze the state of ships in the whole channel.This method had been successfully applied to the analysis of flat channel in inland rivers,but it was seldom applied to the study of inshore channel.Especially in the curve channel,it was never be used of this kind of method.Therefore,based on the original crossing-line channel analysis method,this thesis proposes a multi-direction cross-line analysis method suitable for offshore channel.The main research contents are as follows:(1)For complex inland channel,an improved multi-directional crossing-line setting method is proposed to improve the statistical accuracy of data in channel analysis.The improved method is to change the original setting of parallel crossing to multi-direction setting,so as to meet the needs of various channels.(2)For curved channel,this paper proposes a method for setting the crossing-line of curved channel: taking the center line of channel as an arc to make a circle,starting from the center of the circle,taking the degree of the center of the circle as the unit,the line segment that the ray cuts across the channel is defined as the crossing line of curved channel.(3)For sector channel,this paper also proposes a method for setting the crossing line of the offshore sector channel: starting from the equidistant point of the center line of the channel,perpendicular lines are made to the left and right sides of the channel boundary respectively,and the line segment that the perpendicular lines cut across the channel is defined as the crossing line of the sector channel.(4)On this basis,a channel analysis method based on multi-directional crossing-line is proposed.The content includes two aspects of analysis and early warning.In the aspect of channel navigation analysis,the statistical analysis model based on crossing-line is established to accurately analyze the navigation characteristics of each ship segment and improve the channel management.In the aspect of ship early warning,the ship grounding risk model based on crossing line is established,and the factor of safe sailing time is added to make the ship grounding risk have better visibility and foresight in time and space,and enhance the navigation safety.After that,this paper also expands the analysis of crossing-line and applies it to the analysis of ship navigation in the offshore field.To refine the boundary marking of offshore channel,this paper adopts the virtual channel construction method based on AIS data to build an offshore implementation environment for crossing-line setting and ship navigation analysis,so as to analyze the characteristics of ship navigation in the offshore.In the experiment,Dalian port and Suez Canal are selected as the objects of analysis.Firstly,based on the offshore waters of Dalian port,the navigation analysis experiment of multi-directional crossing-line is carried out.The experimental results show that the construction method of multi-directional crossing-line is superior to the traditional method in the statistical analysis accuracy of ship navigation characteristics data.Then,through the multi-directional crossing-line in the curved channel and sector channel construction,the offshore channel navigation features and characters of navigation of ships are systematic analyzed,the results also show that the proposed crossing-line setting method in curved channel and sector channel on the accuracy of channel performance is superior to the traditional method.Finally,the proposed method is extended to Suez Canal,and the dynamic grounding risk assessment model of Suez Canal is established to realize the early warning of navigable ships in inland river.The above experimental results show that the research and the proposed method have good scientific verification and analysis effects in the analysis of the offshore navigation of Dalian port and the channel safety of Suez Canal,which proves that the method has high adaptability and wide application prospects in multiple waters.